Add SEV-SNP CipherTextHiding feature support

From: Ashish Kalra <[email protected]>

Define new bit-field definitions returned by SNP_PLATFORM_STATUS command such as new capabilities like SNP_FEATURE_INFO command availability, ciphertext hiding enabled and capability.

Signed-off-by Ashish Kalra <[email protected]>

---
 include/uapi/linux/psp-sev.h | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

include/uapi/linux/psp-sev.h +9 -1

index eeb20dfb1fda..c2fd324623c4 100644
@@ -185,6 +185,10 @@ struct sev_user_data_get_id2 {
  * @mask_chip_id: whether chip id is present in attestation reports or not
  * @mask_chip_key: whether attestation reports are signed or not
  * @vlek_en: VLEK (Version Loaded Endorsement Key) hashstick is loaded
+ * @feature_info: whether SNP_FEATURE_INFO command is available
+ * @rapl_dis: whether RAPL is disabled
+ * @ciphertext_hiding_cap: whether platform has ciphertext hiding capability
+ * @ciphertext_hiding_en: whether ciphertext hiding is enabled
  * @rsvd1: reserved
  * @guest_count: the number of guest currently managed by the firmware
  * @current_tcb_version: current TCB version

@@ -200,7 +204,11 @@ struct sev_user_data_snp_status {
 	__u32 mask_chip_id:1;		/* Out */
 	__u32 mask_chip_key:1;		/* Out */
 	__u32 vlek_en:1;		/* Out */
-	__u32 rsvd1:29;
+	__u32 feature_info:1;		/* Out */
+	__u32 rapl_dis:1;		/* Out */
+	__u32 ciphertext_hiding_cap:1;	/* Out */
+	__u32 ciphertext_hiding_en:1;	/* Out */
+	__u32 rsvd1:25;
 	__u32 guest_count;		/* Out */
 	__u64 current_tcb_version;	/* Out */
 	__u64 reported_tcb_version;	/* Out */

From: Ashish Kalra <[email protected]>

The FEATURE_INFO command provides host and guests a programmatic means

to learn about the supported features of the currently loaded firmware. FEATURE_INFO command leverages the same mechanism as the CPUID instruction. Instead of using the CPUID instruction to retrieve Fn8000_0024, software can use FEATURE_INFO.

The hypervisor may provide Fn8000_0024 values to the guest via the CPUID page in SNP_LAUNCH_UPDATE. As with all CPUID output recorded in that page, the hypervisor can filter Fn8000_0024. The firmware will examine Fn8000_0024 and apply its CPUID policy.

Switch to using SNP platform status instead of SEV platform status if SNP is enabled and cache SNP platform status and feature information from CPUID 0x8000_0024, sub-function 0, in the sev_device structure.

Signed-off-by Ashish Kalra <[email protected]>

---
 drivers/crypto/ccp/sev-dev.c | 81 ++++++++++++++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.h |  3 ++
 include/linux/psp-sev.h      | 29 +++++++++++++
 3 files changed, 113 insertions(+)

drivers/crypto/ccp/sev-dev.c +4 -0

index 3451bada884e..b642f1183b8b 100644
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd)
 	case SEV_CMD_SNP_GUEST_REQUEST:		return sizeof(struct sev_data_snp_guest_request);
 	case SEV_CMD_SNP_CONFIG:		return sizeof(struct sev_user_data_snp_config);
 	case SEV_CMD_SNP_COMMIT:		return sizeof(struct sev_data_snp_commit);
+	case SEV_CMD_SNP_FEATURE_INFO:		return sizeof(struct sev_data_snp_feature_info);
 	default:				return 0;
 	}
 

@@ -1073,6 +1074,69 @@ static void snp_set_hsave_pa(void *arg)
 	wrmsrq(MSR_VM_HSAVE_PA, 0);
 }
 
+static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
+{
+	struct sev_data_snp_feature_info snp_feat_info;

drivers/crypto/ccp/sev-dev.c +5 -0

+
+	/*
+	 * Do feature discovery of the currently loaded firmware,
+	 * and cache feature information from CPUID 0x8000_0024,
+	 * sub-function 0.

drivers/crypto/ccp/sev-dev.c +19 -0

+		if (!rc)
+			sev->feat_info = *feat_info;
+		else
+			dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",
+				rc, *error);
+
+		__free_page(page);
+	}
+
+	return rc;
+}
+
 static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
 {
 	struct sev_data_range_list *range_list = arg;

@@ -1597,6 +1661,23 @@ static int sev_get_api_version(void)
 	struct sev_user_data_status status;
 	int error = 0, ret;
 
+	/*
+	 * Use SNP platform status if SNP is enabled and cache
+	 * SNP platform status and SNP feature information.
+	 */
+	if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) {
+		ret = snp_get_platform_data(&status, &error);
+		if (ret) {

drivers/crypto/ccp/sev-dev.c +0 -0

 	ret = sev_platform_status(&status, &error);
 	if (ret) {
 		dev_err(sev->dev,

drivers/crypto/ccp/sev-dev.h +3 -0

index 3e4e5574e88a..1c1a51e52d2b 100644
@@ -57,6 +57,9 @@ struct sev_device {
 	bool cmd_buf_backup_active;
 
 	bool snp_initialized;
+
+	struct sev_user_data_snp_status snp_plat_status;
+	struct snp_feature_info feat_info;
 };
 
 int sev_dev_init(struct psp_device *psp);

include/linux/psp-sev.h +29 -0

index 0b3a36bdaa90..0149d4a6aceb 100644
@@ -107,6 +107,7 @@ enum sev_cmd {
 	SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,
 	SEV_CMD_SNP_COMMIT		= 0x0CB,
 	SEV_CMD_SNP_VLEK_LOAD		= 0x0CD,
+	SEV_CMD_SNP_FEATURE_INFO	= 0x0CE,
 
 	SEV_CMD_MAX,
 };

@@ -812,6 +813,34 @@ struct sev_data_snp_commit {
 	u32 len;
 } __packed;
 
+/**
+ * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure
+ *
+ * @length: len of the command buffer read by the PSP
+ * @ecx_in: subfunction index
+ * @feature_info_paddr : SPA of the FEATURE_INFO structure
+ */
+struct sev_data_snp_feature_info {
+	u32 length;
+	u32 ecx_in;
+	u64 feature_info_paddr;
+} __packed;
+
+/**
+ * struct feature_info - FEATURE_INFO structure
+ *
+ * @eax: output of SNP_FEATURE_INFO command
+ * @ebx: output of SNP_FEATURE_INFO command
+ * @ecx: output of SNP_FEATURE_INFO command
+ * #edx: output of SNP_FEATURE_INFO command
+ */
+struct snp_feature_info {
+	u32 eax;
+	u32 ebx;
+	u32 ecx;
+	u32 edx;
+} __packed;
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**

Quoted 3 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

The FEATURE_INFO command provides host and guests a programmatic means

s/provides host and guests/provides hypervisors/

Quoted 5 lines

to learn about the supported features of the currently loaded firmware. FEATURE_INFO command leverages the same mechanism as the CPUID instruction. Instead of using the CPUID instruction to retrieve Fn8000_0024, software can use FEATURE_INFO.

Quoted 4 lines

The hypervisor may provide Fn8000_0024 values to the guest via the CPUID page in SNP_LAUNCH_UPDATE. As with all CPUID output recorded in that page, the hypervisor can filter Fn8000_0024. The firmware will examine Fn8000_0024 and apply its CPUID policy.

This paragraph has nothing to do with this patch, please remove it.

Quoted 5 lines

Switch to using SNP platform status instead of SEV platform status if SNP is enabled and cache SNP platform status and feature information from CPUID 0x8000_0024, sub-function 0, in the sev_device structure.

Since the SEV platform status and SNP platform status differ, I think this patch should be split into two separate patches.

The first first patch would cache the current SEV platform status return structure and eliminate the separate state field (as state is unique between SEV and SNP).

The api_major/api_minor/build can probably remain,
since the same value *should* be reported for both SNP and SEV platform status command.

The second patch would cache the SNP platform status and feature info data, with this status data being used for the api_major/api_minor/build.

Quoted 33 lines

Signed-off-by Ashish Kalra <[email protected]>

---
 drivers/crypto/ccp/sev-dev.c | 81 ++++++++++++++++++++++++++++++++++++
 drivers/crypto/ccp/sev-dev.h |  3 ++
 include/linux/psp-sev.h      | 29 +++++++++++++
 3 files changed, 113 insertions(+)

drivers/crypto/ccp/sev-dev.c +10 -0

index 3451bada884e..b642f1183b8b 100644
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd)
 	case SEV_CMD_SNP_GUEST_REQUEST:		return sizeof(struct sev_data_snp_guest_request);
 	case SEV_CMD_SNP_CONFIG:		return sizeof(struct sev_user_data_snp_config);
 	case SEV_CMD_SNP_COMMIT:		return sizeof(struct sev_data_snp_commit);
+	case SEV_CMD_SNP_FEATURE_INFO:		return sizeof(struct sev_data_snp_feature_info);
 	default:				return 0;
 	}
 

@@ -1073,6 +1074,69 @@ static void snp_set_hsave_pa(void *arg)
 	wrmsrq(MSR_VM_HSAVE_PA, 0);
 }
 
+static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
+{
+	struct sev_data_snp_feature_info snp_feat_info;
+	struct sev_device *sev = psp_master->sev_data;
+	struct snp_feature_info *feat_info;
+	struct sev_data_snp_addr buf;
+	struct page *page;
+	int rc;
+

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1089

Quoted 4 lines

drivers/crypto/ccp/sev-dev.c +4 -0

+	/*
+	 * The output buffer must be firmware page if SEV-SNP is
+	 * initialized.
+	 */

This comment should be expanded and say that this function is intended to be called when SNP is not initialized or you make this work for both situations.

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1095

Quoted 6 lines

drivers/crypto/ccp/sev-dev.c +6 -0

+	if (sev->snp_initialized)
+		return -EINVAL;
+
+	buf.address = __psp_pa(&sev->snp_plat_status);
+	rc = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, error);
+

Remove blank line.

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1105

Quoted 10 lines

drivers/crypto/ccp/sev-dev.c +10 -0

+	if (rc) {
+		dev_err(sev->dev, "SNP PLATFORM_STATUS command failed, ret = %d, error = %#x\n",
+			rc, *error);
+		return rc;
+	}
+
+	status->api_major = sev->snp_plat_status.api_major;
+	status->api_minor = sev->snp_plat_status.api_minor;
+	status->build = sev->snp_plat_status.build_id;
+	status->state = sev->snp_plat_status.state;

This may need to be moved based on how the patches lay out.

Quoted 5 lines

drivers/crypto/ccp/sev-dev.c +5 -0

+
+	/*
+	 * Do feature discovery of the currently loaded firmware,
+	 * and cache feature information from CPUID 0x8000_0024,
+	 * sub-function 0.

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1120

Quoted 10 lines

drivers/crypto/ccp/sev-dev.c +10 -0

+	 */
+	if (sev->snp_plat_status.feature_info) {
+		/*
+		 * Use dynamically allocated structure for the SNP_FEATURE_INFO
+		 * command to handle any alignment and page boundary check
+		 * requirements.
+		 */
+		page = alloc_page(GFP_KERNEL);
+		if (!page)
+			return -ENOMEM;

Add a blank line.

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1127

Quoted 7 lines

drivers/crypto/ccp/sev-dev.c +7 -0

+		feat_info = page_address(page);
+		snp_feat_info.length = sizeof(snp_feat_info);
+		snp_feat_info.ecx_in = 0;
+		snp_feat_info.feature_info_paddr = __psp_pa(feat_info);
+
+		rc = __sev_do_cmd_locked(SEV_CMD_SNP_FEATURE_INFO, &snp_feat_info, error);
+

Remove blank line.

Quoted 31 lines

drivers/crypto/ccp/sev-dev.c +24 -0

+		if (!rc)
+			sev->feat_info = *feat_info;
+		else
+			dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",
+				rc, *error);
+
+		__free_page(page);
+	}
+
+	return rc;
+}
+
 static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
 {
 	struct sev_data_range_list *range_list = arg;

@@ -1597,6 +1661,23 @@ static int sev_get_api_version(void)
 	struct sev_user_data_status status;
 	int error = 0, ret;
 
+	/*
+	 * Use SNP platform status if SNP is enabled and cache
+	 * SNP platform status and SNP feature information.
+	 */
+	if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) {
+		ret = snp_get_platform_data(&status, &error);
+		if (ret) {
+			dev_err(sev->dev,
+				"SEV-SNP: failed to get status. Error: %#x\n", error);
+			return 1;
+		}
+	}

drivers/crypto/ccp/sev-dev.c static int sev_get_api_version(void) · line 1680

Quoted 5 lines

drivers/crypto/ccp/sev-dev.c +5 -0

+
+	/*
+	 * Fallback to SEV platform status if SNP is not enabled
+	 * or SNP platform status fails.
+	 */

I think this comment is incorrect, aren't you calling this on success of snp_get_platform_data() and returning on error?

You want both platform status outputs cached. So the above behavior is correct, I believe, that we error out on SNP platform status failure.

Thanks,
Tom

Quoted 64 lines

drivers/crypto/ccp/sev-dev.c +0 -0

 	ret = sev_platform_status(&status, &error);
 	if (ret) {
 		dev_err(sev->dev,

drivers/crypto/ccp/sev-dev.h +3 -0

index 3e4e5574e88a..1c1a51e52d2b 100644
@@ -57,6 +57,9 @@ struct sev_device {
 	bool cmd_buf_backup_active;
 
 	bool snp_initialized;
+
+	struct sev_user_data_snp_status snp_plat_status;
+	struct snp_feature_info feat_info;
 };
 
 int sev_dev_init(struct psp_device *psp);

include/linux/psp-sev.h +29 -0

index 0b3a36bdaa90..0149d4a6aceb 100644
@@ -107,6 +107,7 @@ enum sev_cmd {
 	SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,
 	SEV_CMD_SNP_COMMIT		= 0x0CB,
 	SEV_CMD_SNP_VLEK_LOAD		= 0x0CD,
+	SEV_CMD_SNP_FEATURE_INFO	= 0x0CE,
 
 	SEV_CMD_MAX,
 };

@@ -812,6 +813,34 @@ struct sev_data_snp_commit {
 	u32 len;
 } __packed;
 
+/**
+ * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure
+ *
+ * @length: len of the command buffer read by the PSP
+ * @ecx_in: subfunction index
+ * @feature_info_paddr : SPA of the FEATURE_INFO structure
+ */
+struct sev_data_snp_feature_info {
+	u32 length;
+	u32 ecx_in;
+	u64 feature_info_paddr;
+} __packed;
+
+/**
+ * struct feature_info - FEATURE_INFO structure
+ *
+ * @eax: output of SNP_FEATURE_INFO command
+ * @ebx: output of SNP_FEATURE_INFO command
+ * @ecx: output of SNP_FEATURE_INFO command
+ * #edx: output of SNP_FEATURE_INFO command
+ */
+struct snp_feature_info {
+	u32 eax;
+	u32 ebx;
+	u32 ecx;
+	u32 edx;
+} __packed;
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**

Hello Tom,

Quoted 8 lines · Tom Lendacky

Quoted 6 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Switch to using SNP platform status instead of SEV platform status if SNP is enabled and cache SNP platform status and feature information from CPUID 0x8000_0024, sub-function 0, in the sev_device structure.

Quoted 6 lines

Since the SEV platform status and SNP platform status differ, I think this patch should be split into two separate patches.

The first first patch would cache the current SEV platform status return structure and eliminate the separate state field (as state is unique between SEV and SNP).

Eliminate the state field ?

But isn't the sev_device->state field used also as driver's internal state information and not directly mapped to platform status, except the initial state is the platform state on module load, so why to remove the field altogether ?

From: Ashish Kalra <[email protected]>

The FEATURE_INFO command provides host and guests a programmatic means to learn about the supported features of the currently loaded firmware. FEATURE_INFO command leverages the same mechanism as the CPUID instruction. Instead of using the CPUID instruction to retrieve Fn8000_0024, software can use FEATURE_INFO.

The hypervisor may provide Fn8000_0024 values to the guest via the CPUID page in SNP_LAUNCH_UPDATE. As with all CPUID output recorded in that page, the hypervisor can filter Fn8000_0024. The firmware will examine Fn8000_0024 and apply its CPUID policy.

Switch to using SNP platform status instead of SEV platform status if SNP is enabled and cache SNP platform status and feature information from CPUID 0x8000_0024, sub-function 0, in the sev_device structure.

Signed-off-by Ashish Kalra <[email protected]>

---
  drivers/crypto/ccp/sev-dev.c | 81 ++++++++++++++++++++++++++++++++++++
  drivers/crypto/ccp/sev-dev.h |  3 ++
  include/linux/psp-sev.h      | 29 +++++++++++++
  3 files changed, 113 insertions(+)

drivers/crypto/ccp/sev-dev.c +20 -0

index 3451bada884e..b642f1183b8b 100644
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd)
  	case SEV_CMD_SNP_GUEST_REQUEST:		return sizeof(struct sev_data_snp_guest_request);
  	case SEV_CMD_SNP_CONFIG:		return sizeof(struct sev_user_data_snp_config);
  	case SEV_CMD_SNP_COMMIT:		return sizeof(struct sev_data_snp_commit);
+	case SEV_CMD_SNP_FEATURE_INFO:		return sizeof(struct sev_data_snp_feature_info);
  	default:				return 0;
  	}
 

@@ -1073,6 +1074,69 @@ static void snp_set_hsave_pa(void *arg)
  	wrmsrq(MSR_VM_HSAVE_PA, 0);
  }
 
+static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
+{
+	struct sev_data_snp_feature_info snp_feat_info;
+	struct sev_device *sev = psp_master->sev_data;
+	struct snp_feature_info *feat_info;
+	struct sev_data_snp_addr buf;
+	struct page *page;
+	int rc;
+
+	/*
+	 * The output buffer must be firmware page if SEV-SNP is
+	 * initialized.
+	 */
+	if (sev->snp_initialized)
+		return -EINVAL;
+
+	buf.address = __psp_pa(&sev->snp_plat_status);
+	rc = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, error);
+

drivers/crypto/ccp/sev-dev.c +27 -0

+		/*
+		 * Use dynamically allocated structure for the SNP_FEATURE_INFO
+		 * command to handle any alignment and page boundary check
+		 * requirements.
+		 */
+		page = alloc_page(GFP_KERNEL);
+		if (!page)
+			return -ENOMEM;
+		feat_info = page_address(page);
+		snp_feat_info.length = sizeof(snp_feat_info);
+		snp_feat_info.ecx_in = 0;
+		snp_feat_info.feature_info_paddr = __psp_pa(feat_info);
+
+		rc = __sev_do_cmd_locked(SEV_CMD_SNP_FEATURE_INFO, &snp_feat_info, error);
+
+		if (!rc)
+			sev->feat_info = *feat_info;
+		else
+			dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",
+				rc, *error);
+
+		__free_page(page);
+	}
+
+	return rc;
+}
+
  static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
  {
  	struct sev_data_range_list *range_list = arg;

@@ -1597,6 +1661,23 @@ static int sev_get_api_version(void)
  	struct sev_user_data_status status;
  	int error = 0, ret;

drivers/crypto/ccp/sev-dev.h +0 -0

  };
 
  int sev_dev_init(struct psp_device *psp);

include/linux/psp-sev.h +18 -0

index 0b3a36bdaa90..0149d4a6aceb 100644
@@ -107,6 +107,7 @@ enum sev_cmd {
  	SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,
  	SEV_CMD_SNP_COMMIT		= 0x0CB,
  	SEV_CMD_SNP_VLEK_LOAD		= 0x0CD,
+	SEV_CMD_SNP_FEATURE_INFO	= 0x0CE,
 
  	SEV_CMD_MAX,
  };

@@ -812,6 +813,34 @@ struct sev_data_snp_commit {
  	u32 len;
  } __packed;
 
+/**
+ * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure
+ *
+ * @length: len of the command buffer read by the PSP
+ * @ecx_in: subfunction index
+ * @feature_info_paddr : SPA of the FEATURE_INFO structure
+ */
+struct sev_data_snp_feature_info {
+	u32 length;
+	u32 ecx_in;
+	u64 feature_info_paddr;
+} __packed;
+
+/**
+ * struct feature_info - FEATURE_INFO structure
+ *
+ * @eax: output of SNP_FEATURE_INFO command

include/linux/psp-sev.h +1 -0

+
  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
  /**

Quoted 57 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

The FEATURE_INFO command provides host and guests a programmatic means to learn about the supported features of the currently loaded firmware. FEATURE_INFO command leverages the same mechanism as the CPUID instruction. Instead of using the CPUID instruction to retrieve Fn8000_0024, software can use FEATURE_INFO.

The hypervisor may provide Fn8000_0024 values to the guest via the CPUID page in SNP_LAUNCH_UPDATE. As with all CPUID output recorded in that page, the hypervisor can filter Fn8000_0024. The firmware will examine Fn8000_0024 and apply its CPUID policy.

Switch to using SNP platform status instead of SEV platform status if SNP is enabled and cache SNP platform status and feature information from CPUID 0x8000_0024, sub-function 0, in the sev_device structure.

Signed-off-by Ashish Kalra <[email protected]>

---
  drivers/crypto/ccp/sev-dev.c | 81 ++++++++++++++++++++++++++++++++++++ drivers/crypto/ccp/sev-dev.h |  3 ++ include/linux/psp-sev.h      | 29 +++++++++++++

  3 files changed, 113 insertions(+)

drivers/crypto/ccp/sev-dev.c +1 -0

index 3451bada884e..b642f1183b8b 100644
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd)
       case SEV_CMD_SNP_GUEST_REQUEST:        return sizeof(struct sev_data_snp_guest_request);
       case SEV_CMD_SNP_CONFIG:        return sizeof(struct sev_user_data_snp_config);
       case SEV_CMD_SNP_COMMIT:        return sizeof(struct sev_data_snp_commit);
+    case SEV_CMD_SNP_FEATURE_INFO:        return sizeof(struct sev_data_snp_feature_info);
       default:                return 0;
       }
   @@ -1073,6 +1074,69 @@ static void snp_set_hsave_pa(void *arg)

      wrmsrq(MSR_VM_HSAVE_PA, 0);
  }
  +static int snp_get_platform_data(struct sev_user_data_status *status, int *error)

drivers/crypto/ccp/sev-dev.c +18 -0

+{
+    struct sev_data_snp_feature_info snp_feat_info;
+    struct sev_device *sev = psp_master->sev_data;
+    struct snp_feature_info *feat_info;
+    struct sev_data_snp_addr buf;
+    struct page *page;
+    int rc;
+
+    /*
+     * The output buffer must be firmware page if SEV-SNP is
+     * initialized.
+     */
+    if (sev->snp_initialized)
+        return -EINVAL;
+
+    buf.address = __psp_pa(&sev->snp_plat_status);
+    rc = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, error);
+

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1105

Quoted 10 lines

drivers/crypto/ccp/sev-dev.c +10 -0

+    if (rc) {
+        dev_err(sev->dev, "SNP PLATFORM_STATUS command failed, ret = %d, error = %#x\n",
+            rc, *error);
+        return rc;
+    }
+
+    status->api_major = sev->snp_plat_status.api_major;
+    status->api_minor = sev->snp_plat_status.api_minor;
+    status->build = sev->snp_plat_status.build_id;
+    status->state = sev->snp_plat_status.state;

These 4 lines should be ....

Quoted 7 lines

+
+    /*
+     * Do feature discovery of the currently loaded firmware, +     * and cache feature information from CPUID 0x8000_0024, +     * sub-function 0.
+     */
+    if (sev->snp_plat_status.feature_info) {

Could do:

if (!sev->snp_plat_status.feature_info)
    return 0;

and reduce indentation below.

Quoted 34 lines

+        /*
+         * Use dynamically allocated structure for the SNP_FEATURE_INFO +         * command to handle any alignment and page boundary check +         * requirements.
+         */
+        page = alloc_page(GFP_KERNEL);
+        if (!page)
+            return -ENOMEM;
+        feat_info = page_address(page);
+        snp_feat_info.length = sizeof(snp_feat_info);
+        snp_feat_info.ecx_in = 0;
+        snp_feat_info.feature_info_paddr = __psp_pa(feat_info);

drivers/crypto/ccp/sev-dev.c +15 -0

+
+        rc = __sev_do_cmd_locked(SEV_CMD_SNP_FEATURE_INFO, &snp_feat_info, error);
+
+        if (!rc)
+            sev->feat_info = *feat_info;
+        else
+            dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",
+                rc, *error);
+
+        __free_page(page);
+    }
+
+    return rc;
+}
+

  static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg) {
      struct sev_data_range_list *range_list = arg;

drivers/crypto/ccp/sev-dev.c +0 -0

@@ -1597,6 +1661,23 @@ static int sev_get_api_version(void)
       struct sev_user_data_status status;
       int error = 0, ret;

  +    /*

Quoted 8 lines

+     * Use SNP platform status if SNP is enabled and cache +     * SNP platform status and SNP feature information.
+     */
+    if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) {
+        ret = snp_get_platform_data(&status, &error);
+        if (ret) {
+            dev_err(sev->dev,
+                "SEV-SNP: failed to get status. Error: %#x\n", error);

Drop this as snp_get_platform_data() does that too (and even better as it prints @ret too).

Quoted 2 lines

+            return 1;
+        }

.... here, and drop the @status parameter. Which in fact is pointless anyway as ....

Let snp_get_platform_data() do just SNP stuff.

Quoted 7 lines

+    }
+
+    /*
+     * Fallback to SEV platform status if SNP is not enabled> +     * or SNP platform status fails. +     */
      ret = sev_platform_status(&status, &error);

... this sev_platform_status() is called anyway (not a fallback as the comment above says) and will override whatever snp_get_platform_data() wrote to @status.

drivers/crypto/ccp/sev-dev.h struct sev_device { · line 61

Quoted 13 lines

      if (ret) {
          dev_err(sev->dev,

drivers/crypto/ccp/sev-dev.h +3 -0

index 3e4e5574e88a..1c1a51e52d2b 100644
@@ -57,6 +57,9 @@ struct sev_device {
       bool cmd_buf_backup_active;
         bool snp_initialized;
+
+    struct sev_user_data_snp_status snp_plat_status;
+    struct snp_feature_info feat_info;

"snp_feat_info_0" as 1) it is for SNP like some other fields 2) there is subfunction=1 already defined so need some distinction.

Quoted 34 lines

drivers/crypto/ccp/sev-dev.h +0 -0

   };
     int sev_dev_init(struct psp_device *psp);

include/linux/psp-sev.h +1 -0

index 0b3a36bdaa90..0149d4a6aceb 100644
@@ -107,6 +107,7 @@ enum sev_cmd {
       SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,
       SEV_CMD_SNP_COMMIT        = 0x0CB,
       SEV_CMD_SNP_VLEK_LOAD        = 0x0CD,
+    SEV_CMD_SNP_FEATURE_INFO    = 0x0CE,
         SEV_CMD_MAX,
   };

@@ -812,6 +813,34 @@ struct sev_data_snp_commit {
       u32 len;
   } __packed;

  +/**
+ * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure
+ *
+ * @length: len of the command buffer read by the PSP
+ * @ecx_in: subfunction index
+ * @feature_info_paddr : SPA of the FEATURE_INFO structure
+ */

include/linux/psp-sev.h +10 -0

+struct sev_data_snp_feature_info {
+    u32 length;
+    u32 ecx_in;
+    u64 feature_info_paddr;
+} __packed;
+
+/**
+ * struct feature_info - FEATURE_INFO structure
+ *
+ * @eax: output of SNP_FEATURE_INFO command

include/linux/psp-sev.h struct sev_data_snp_commit { · line 842

Quoted 10 lines

include/linux/psp-sev.h +10 -0

+ * @ebx: output of SNP_FEATURE_INFO command
+ * @ecx: output of SNP_FEATURE_INFO command
+ * #edx: output of SNP_FEATURE_INFO command
+ */
+struct snp_feature_info {
+    u32 eax;
+    u32 ebx;
+    u32 ecx;
+    u32 edx;
+} __packed;

(not insisting) You could even define this as "struct snp_feature_info_0" with all the bits from "Table 5. Contents of Each Subfunction of Fn8000_0024". Thanks,

Quoted 3 lines

+
  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
    /**

From: Ashish Kalra <[email protected]>

Ciphertext hiding needs to be enabled on SNP_INIT_EX.

Add new argument to sev_platform_init_args to allow KVM module to specify during SNP initialization if CipherTextHiding feature is to be enabled and the maximum ASID usable for an SEV-SNP guest when CipherTextHiding feature is enabled.

Add new API interface to indicate if SEV-SNP CipherTextHiding feature is supported by SEV firmware and additionally if CipherTextHiding feature is enabled in the Platform BIOS.

Signed-off-by Ashish Kalra <[email protected]>

---
 drivers/crypto/ccp/sev-dev.c | 30 +++++++++++++++++++++++++++---
 include/linux/psp-sev.h      | 15 +++++++++++++--
 2 files changed, 40 insertions(+), 5 deletions(-)

drivers/crypto/ccp/sev-dev.c +0 -0

index b642f1183b8b..185668477182 100644

drivers/crypto/ccp/sev-dev.c +8 -2

 {
 	struct psp_device *psp = psp_master;
 	struct sev_data_snp_init_ex data;

@@ -1228,6 +1246,12 @@ static int __sev_snp_init_locked(int *error)
 		}
 
 		memset(&data, 0, sizeof(data));
+
+		if (snp_max_snp_asid) {
+			data.ciphertext_hiding_en = 1;
+			data.max_snp_asid = snp_max_snp_asid;
+		}
+
 		data.init_rmp = 1;
 		data.list_paddr_en = 1;
 		data.list_paddr = __psp_pa(snp_range_list);

@@ -1412,7 +1436,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
 	if (sev->state == SEV_STATE_INIT)
 		return 0;
 
-	rc = __sev_snp_init_locked(&args->error);
+	rc = __sev_snp_init_locked(&args->error, args->snp_max_snp_asid);
 	if (rc && rc != -ENODEV)
 		return rc;
 

@@ -1495,7 +1519,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
 {
 	int error, rc;
 
-	rc = __sev_snp_init_locked(&error);
+	rc = __sev_snp_init_locked(&error, 0);
 	if (rc) {
 		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
 		return rc;

include/linux/psp-sev.h +5 -2

index 0149d4a6aceb..66fecd0c0f88 100644
@@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
 struct sev_data_snp_init_ex {
 	u32 init_rmp:1;
 	u32 list_paddr_en:1;
-	u32 rsvd:30;
+	u32 rapl_dis:1;
+	u32 ciphertext_hiding_en:1;
+	u32 rsvd:28;
 	u32 rsvd1;
 	u64 list_paddr;
-	u8  rsvd2[48];
+	u16 max_snp_asid;
+	u8  rsvd2[46];
 } __packed;
 
 /**

include/linux/psp-sev.h +5 -0

 };
 
 /**

@@ -841,6 +847,8 @@ struct snp_feature_info {
 	u32 edx;
 } __packed;
 
+#define SNP_CIPHER_TEXT_HIDING_SUPPORTED	BIT(3)
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**

@@ -984,6 +992,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
 void *snp_alloc_firmware_page(gfp_t mask);
 void snp_free_firmware_page(void *addr);
 void sev_platform_shutdown(void);
+bool sev_is_snp_ciphertext_hiding_supported(void);
 
 #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
 

@@ -1020,6 +1029,8 @@ static inline void snp_free_firmware_page(void *addr) { }
 
 static inline void sev_platform_shutdown(void) { }
 
+static inline bool sev_is_snp_ciphertext_hiding_supported(void) { return false; }
+
 #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
 
 #endif	/* __PSP_SEV_H__ */

Quoted 27 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Ciphertext hiding needs to be enabled on SNP_INIT_EX.

Add new argument to sev_platform_init_args to allow KVM module to specify during SNP initialization if CipherTextHiding feature is to be enabled and the maximum ASID usable for an SEV-SNP guest when CipherTextHiding feature is enabled.

Add new API interface to indicate if SEV-SNP CipherTextHiding feature is supported by SEV firmware and additionally if CipherTextHiding feature is enabled in the Platform BIOS.

Signed-off-by Ashish Kalra <[email protected]>

---
 drivers/crypto/ccp/sev-dev.c | 30 +++++++++++++++++++++++++++---
 include/linux/psp-sev.h      | 15 +++++++++++++--
 2 files changed, 40 insertions(+), 5 deletions(-)

drivers/crypto/ccp/sev-dev.c +0 -0

index b642f1183b8b..185668477182 100644
@@ -1074,6 +1074,24 @@ static void snp_set_hsave_pa(void *arg)
 	wrmsrq(MSR_VM_HSAVE_PA, 0);
 }
 

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1082

Quoted 6 lines

drivers/crypto/ccp/sev-dev.c +6 -0

+bool sev_is_snp_ciphertext_hiding_supported(void)
+{
+	struct psp_device *psp = psp_master;
+	struct sev_device *sev;
+
+	sev = psp->sev_data;

This needs a check for !psp and !psp->sev_data before de-referencing them.

drivers/crypto/ccp/sev-dev.c static void snp_set_hsave_pa(void *arg) · line 1091

Quoted 9 lines

drivers/crypto/ccp/sev-dev.c +9 -0

+
+	/*
+	 * Feature information indicates if CipherTextHiding feature is
+	 * supported by the SEV firmware and additionally platform status
+	 * indicates if CipherTextHiding feature is enabled in the
+	 * Platform BIOS.
+	 */
+	return ((sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
+	    sev->snp_plat_status.ciphertext_hiding_cap);

Alignment.

Quoted 10 lines

drivers/crypto/ccp/sev-dev.c +3 -0

+}
+EXPORT_SYMBOL_GPL(sev_is_snp_ciphertext_hiding_supported);
+
 static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
 {
 	struct sev_data_snp_feature_info snp_feat_info;

@@ -1167,7 +1185,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
 	return 0;
 }
 

drivers/crypto/ccp/sev-dev.c static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg) · line 1188

Quoted 2 lines

drivers/crypto/ccp/sev-dev.c +1 -1

-static int __sev_snp_init_locked(int *error)
+static int __sev_snp_init_locked(int *error, unsigned int snp_max_snp_asid)

s/snp_max_snp_asid/max_snp_asid/

Quoted 55 lines

drivers/crypto/ccp/sev-dev.c +8 -2

 {
 	struct psp_device *psp = psp_master;
 	struct sev_data_snp_init_ex data;

@@ -1228,6 +1246,12 @@ static int __sev_snp_init_locked(int *error)
 		}
 
 		memset(&data, 0, sizeof(data));
+
+		if (snp_max_snp_asid) {
+			data.ciphertext_hiding_en = 1;
+			data.max_snp_asid = snp_max_snp_asid;
+		}
+
 		data.init_rmp = 1;
 		data.list_paddr_en = 1;
 		data.list_paddr = __psp_pa(snp_range_list);

@@ -1412,7 +1436,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
 	if (sev->state == SEV_STATE_INIT)
 		return 0;
 
-	rc = __sev_snp_init_locked(&args->error);
+	rc = __sev_snp_init_locked(&args->error, args->snp_max_snp_asid);
 	if (rc && rc != -ENODEV)
 		return rc;
 

@@ -1495,7 +1519,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
 {
 	int error, rc;
 
-	rc = __sev_snp_init_locked(&error);
+	rc = __sev_snp_init_locked(&error, 0);
 	if (rc) {
 		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
 		return rc;

include/linux/psp-sev.h +5 -2

index 0149d4a6aceb..66fecd0c0f88 100644
@@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
 struct sev_data_snp_init_ex {
 	u32 init_rmp:1;
 	u32 list_paddr_en:1;
-	u32 rsvd:30;
+	u32 rapl_dis:1;
+	u32 ciphertext_hiding_en:1;
+	u32 rsvd:28;
 	u32 rsvd1;
 	u64 list_paddr;
-	u8  rsvd2[48];
+	u16 max_snp_asid;
+	u8  rsvd2[46];
 } __packed;
 
 /**

include/linux/psp-sev.h struct sev_data_snp_shutdown_ex { · line 804

Quoted 4 lines

include/linux/psp-sev.h +1 -0

@@ -798,10 +801,13 @@ struct sev_data_snp_shutdown_ex {
  * @probe: True if this is being called as part of CCP module probe, which
  *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
  *  unless psp_init_on_probe module param is set
+ *  @snp_max_snp_asid: maximum ASID usable for SEV-SNP guest if

Only a single space between the "*" and the "@"

s/snp_max_snp_asid/max_snp_asid/

include/linux/psp-sev.h struct sev_data_snp_shutdown_ex { · line 810

Quoted 6 lines

include/linux/psp-sev.h +2 -0

+ *  CipherTextHiding feature is to be enabled
  */
 struct sev_platform_init_args {
 	int error;
 	bool probe;
+	unsigned int snp_max_snp_asid;

s/snp_max_snp_asid/max_snp_asid/

Thanks,
Tom

Quoted 29 lines

include/linux/psp-sev.h +5 -0

 };
 
 /**

@@ -841,6 +847,8 @@ struct snp_feature_info {
 	u32 edx;
 } __packed;
 
+#define SNP_CIPHER_TEXT_HIDING_SUPPORTED	BIT(3)
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**

@@ -984,6 +992,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
 void *snp_alloc_firmware_page(gfp_t mask);
 void snp_free_firmware_page(void *addr);
 void sev_platform_shutdown(void);
+bool sev_is_snp_ciphertext_hiding_supported(void);
 
 #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
 

@@ -1020,6 +1029,8 @@ static inline void snp_free_firmware_page(void *addr) { }
 
 static inline void sev_platform_shutdown(void) { }
 
+static inline bool sev_is_snp_ciphertext_hiding_supported(void) { return false; }
+
 #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
 
 #endif	/* __PSP_SEV_H__ */

From: Ashish Kalra <[email protected]>

Ciphertext hiding needs to be enabled on SNP_INIT_EX.

Add new argument to sev_platform_init_args to allow KVM module to specify during SNP initialization if CipherTextHiding feature is to be enabled and the maximum ASID usable for an SEV-SNP guest when CipherTextHiding feature is enabled.

Add new API interface to indicate if SEV-SNP CipherTextHiding feature is supported by SEV firmware and additionally if CipherTextHiding feature is enabled in the Platform BIOS.

Signed-off-by Ashish Kalra <[email protected]>

---
  drivers/crypto/ccp/sev-dev.c | 30 +++++++++++++++++++++++++++---
  include/linux/psp-sev.h      | 15 +++++++++++++--
  2 files changed, 40 insertions(+), 5 deletions(-)

drivers/crypto/ccp/sev-dev.c +27 -3

index b642f1183b8b..185668477182 100644
@@ -1074,6 +1074,24 @@ static void snp_set_hsave_pa(void *arg)
  	wrmsrq(MSR_VM_HSAVE_PA, 0);
  }
 
+bool sev_is_snp_ciphertext_hiding_supported(void)
+{
+	struct psp_device *psp = psp_master;
+	struct sev_device *sev;
+
+	sev = psp->sev_data;
+
+	/*
+	 * Feature information indicates if CipherTextHiding feature is
+	 * supported by the SEV firmware and additionally platform status
+	 * indicates if CipherTextHiding feature is enabled in the
+	 * Platform BIOS.
+	 */
+	return ((sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
+	    sev->snp_plat_status.ciphertext_hiding_cap);
+}
+EXPORT_SYMBOL_GPL(sev_is_snp_ciphertext_hiding_supported);
+
  static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
  {
  	struct sev_data_snp_feature_info snp_feat_info;

@@ -1167,7 +1185,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
  	return 0;
  }
 
-static int __sev_snp_init_locked(int *error)
+static int __sev_snp_init_locked(int *error, unsigned int snp_max_snp_asid)
  {
  	struct psp_device *psp = psp_master;
  	struct sev_data_snp_init_ex data;

@@ -1228,6 +1246,12 @@ static int __sev_snp_init_locked(int *error)
  		}
 
  		memset(&data, 0, sizeof(data));
+
+		if (snp_max_snp_asid) {
+			data.ciphertext_hiding_en = 1;
+			data.max_snp_asid = snp_max_snp_asid;
+		}
+
  		data.init_rmp = 1;
  		data.list_paddr_en = 1;
  		data.list_paddr = __psp_pa(snp_range_list);

@@ -1412,7 +1436,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
  	if (sev->state == SEV_STATE_INIT)
  		return 0;
 
-	rc = __sev_snp_init_locked(&args->error);
+	rc = __sev_snp_init_locked(&args->error, args->snp_max_snp_asid);
  	if (rc && rc != -ENODEV)
  		return rc;
 

@@ -1495,7 +1519,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
  {
  	int error, rc;
 
-	rc = __sev_snp_init_locked(&error);
+	rc = __sev_snp_init_locked(&error, 0);
  	if (rc) {
  		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
  		return rc;

include/linux/psp-sev.h +8 -2

index 0149d4a6aceb..66fecd0c0f88 100644
@@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
  struct sev_data_snp_init_ex {
  	u32 init_rmp:1;
  	u32 list_paddr_en:1;
-	u32 rsvd:30;
+	u32 rapl_dis:1;
+	u32 ciphertext_hiding_en:1;
+	u32 rsvd:28;
  	u32 rsvd1;
  	u64 list_paddr;
-	u8  rsvd2[48];
+	u16 max_snp_asid;
+	u8  rsvd2[46];
  } __packed;
 
  /**

@@ -798,10 +801,13 @@ struct sev_data_snp_shutdown_ex {
   * @probe: True if this is being called as part of CCP module probe, which
   *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
   *  unless psp_init_on_probe module param is set
+ *  @snp_max_snp_asid: maximum ASID usable for SEV-SNP guest if
+ *  CipherTextHiding feature is to be enabled
   */
  struct sev_platform_init_args {
  	int error;
  	bool probe;
+	unsigned int snp_max_snp_asid;
  };
 
  /**

include/linux/psp-sev.h +4 -0

+
  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
  /**

@@ -984,6 +992,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
  void *snp_alloc_firmware_page(gfp_t mask);
  void snp_free_firmware_page(void *addr);
  void sev_platform_shutdown(void);
+bool sev_is_snp_ciphertext_hiding_supported(void);
 
  #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
 

@@ -1020,6 +1029,8 @@ static inline void snp_free_firmware_page(void *addr) { }
 
  static inline void sev_platform_shutdown(void) { }
 
+static inline bool sev_is_snp_ciphertext_hiding_supported(void) { return false; }
+
  #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
 
  #endif	/* __PSP_SEV_H__ */

Quoted 115 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Ciphertext hiding needs to be enabled on SNP_INIT_EX.

Add new argument to sev_platform_init_args to allow KVM module to specify during SNP initialization if CipherTextHiding feature is to be enabled and the maximum ASID usable for an SEV-SNP guest when CipherTextHiding feature is enabled.

Add new API interface to indicate if SEV-SNP CipherTextHiding feature is supported by SEV firmware and additionally if CipherTextHiding feature is enabled in the Platform BIOS.

Signed-off-by Ashish Kalra <[email protected]>

---
  drivers/crypto/ccp/sev-dev.c | 30 +++++++++++++++++++++++++++--- include/linux/psp-sev.h      | 15 +++++++++++++--

  2 files changed, 40 insertions(+), 5 deletions(-)

drivers/crypto/ccp/sev-dev.c +25 -0

index b642f1183b8b..185668477182 100644
@@ -1074,6 +1074,24 @@ static void snp_set_hsave_pa(void *arg)
       wrmsrq(MSR_VM_HSAVE_PA, 0);
   }
   +bool sev_is_snp_ciphertext_hiding_supported(void)
+{
+    struct psp_device *psp = psp_master;
+    struct sev_device *sev;
+
+    sev = psp->sev_data;
+
+    /*
+     * Feature information indicates if CipherTextHiding feature is
+     * supported by the SEV firmware and additionally platform status
+     * indicates if CipherTextHiding feature is enabled in the
+     * Platform BIOS.
+     */
+    return ((sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
+        sev->snp_plat_status.ciphertext_hiding_cap);
+}
+EXPORT_SYMBOL_GPL(sev_is_snp_ciphertext_hiding_supported);
+
   static int snp_get_platform_data(struct sev_user_data_status *status, int *error)
   {
       struct sev_data_snp_feature_info snp_feat_info;

@@ -1167,7 +1185,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
       return 0;
   }
   -static int __sev_snp_init_locked(int *error)
+static int __sev_snp_init_locked(int *error, unsigned int snp_max_snp_asid)
   {
       struct psp_device *psp = psp_master;
       struct sev_data_snp_init_ex data;

@@ -1228,6 +1246,12 @@ static int __sev_snp_init_locked(int *error)
           }
             memset(&data, 0, sizeof(data));
+
+        if (snp_max_snp_asid) {
+            data.ciphertext_hiding_en = 1;
+            data.max_snp_asid = snp_max_snp_asid;
+        }
+
           data.init_rmp = 1;
           data.list_paddr_en = 1;
           data.list_paddr = __psp_pa(snp_range_list);

@@ -1412,7 +1436,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
       if (sev->state == SEV_STATE_INIT)
           return 0;
   -    rc = __sev_snp_init_locked(&args->error);
+    rc = __sev_snp_init_locked(&args->error, args->snp_max_snp_asid);
       if (rc && rc != -ENODEV)
           return rc;

  @@ -1495,7 +1519,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req {
      int error, rc;
  -    rc = __sev_snp_init_locked(&error);
+    rc = __sev_snp_init_locked(&error, 0);
      if (rc) {
          argp->error = SEV_RET_INVALID_PLATFORM_STATE;
          return rc;

include/linux/psp-sev.h +8 -2

index 0149d4a6aceb..66fecd0c0f88 100644
@@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
   struct sev_data_snp_init_ex {
       u32 init_rmp:1;
       u32 list_paddr_en:1;
-    u32 rsvd:30;
+    u32 rapl_dis:1;
+    u32 ciphertext_hiding_en:1;
+    u32 rsvd:28;
       u32 rsvd1;
       u64 list_paddr;
-    u8  rsvd2[48];
+    u16 max_snp_asid;
+    u8  rsvd2[46];
   } __packed;
     /**

@@ -798,10 +801,13 @@ struct sev_data_snp_shutdown_ex {
    * @probe: True if this is being called as part of CCP module probe, which
    *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
    *  unless psp_init_on_probe module param is set
+ *  @snp_max_snp_asid: maximum ASID usable for SEV-SNP guest if
+ *  CipherTextHiding feature is to be enabled
    */
   struct sev_platform_init_args {
       int error;
       bool probe;
+    unsigned int snp_max_snp_asid;
   };
     /**

include/linux/psp-sev.h struct snp_feature_info { · line 849

Quoted 3 lines

include/linux/psp-sev.h +0 -0

@@ -841,6 +847,8 @@ struct snp_feature_info {
       u32 edx;
   } __packed;
   +#define SNP_CIPHER_TEXT_HIDING_SUPPORTED    BIT(3)

SNP_FEATURE_CIPHER_TEXT_HIDING ?
or X86_FEATURE_CIPHER_TEXT_HIDING ?

In other words, mimic X86_FEATURE_SEV which is a real CPUID bit and FEATURE_INFO mimics CPUID. Thanks,

Quoted 16 lines

include/linux/psp-sev.h +2 -0

+
   #ifdef CONFIG_CRYPTO_DEV_SP_PSP
     /**

@@ -984,6 +992,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
   void *snp_alloc_firmware_page(gfp_t mask);
   void snp_free_firmware_page(void *addr);
   void sev_platform_shutdown(void);
+bool sev_is_snp_ciphertext_hiding_supported(void);
     #else    /* !CONFIG_CRYPTO_DEV_SP_PSP */
   @@ -1020,6 +1029,8 @@ static inline void snp_free_firmware_page(void *addr) { }
     static inline void sev_platform_shutdown(void) { }

  +static inline bool sev_is_snp_ciphertext_hiding_supported(void) { return false; } +
  #endif    /* CONFIG_CRYPTO_DEV_SP_PSP */
    #endif    /* __PSP_SEV_H__ */

From: Ashish Kalra <[email protected]>

Introduce new min, max sev_es_asid and sev_snp_asid variables.

The new {min,max}_{sev_es,snp}_asid variables along with existing {min,max}_sev_asid variable simplifies partitioning of the SEV and SEV-ES+ ASID space.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
 arch/x86/kvm/svm/sev.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

arch/x86/kvm/svm/sev.c +12 -6

index dea9480b9ff6..383db1da8699 100644
@@ -85,6 +85,10 @@ static DECLARE_RWSEM(sev_deactivate_lock);
 static DEFINE_MUTEX(sev_bitmap_lock);
 unsigned int max_sev_asid;
 static unsigned int min_sev_asid;
+static unsigned int max_sev_es_asid;
+static unsigned int min_sev_es_asid;
+static unsigned int max_snp_asid;
+static unsigned int min_snp_asid;
 static unsigned long sev_me_mask;
 static unsigned int nr_asids;
 static unsigned long *sev_asid_bitmap;

@@ -172,20 +176,32 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
 	misc_cg_uncharge(type, sev->misc_cg, 1);
 }
 
-static int sev_asid_new(struct kvm_sev_info *sev)
+static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
 {
 	/*
 	 * SEV-enabled guests must use asid from min_sev_asid to max_sev_asid.
 	 * SEV-ES-enabled guest can use from 1 to min_sev_asid - 1.
-	 * Note: min ASID can end up larger than the max if basic SEV support is
-	 * effectively disabled by disallowing use of ASIDs for SEV guests.
 	 */
-	unsigned int min_asid = sev->es_active ? 1 : min_sev_asid;
-	unsigned int max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
-	unsigned int asid;
+	unsigned int min_asid, max_asid, asid;
 	bool retry = true;
 	int ret;
 
+	if (vm_type == KVM_X86_SNP_VM) {
+		min_asid = min_snp_asid;
+		max_asid = max_snp_asid;
+	} else if (sev->es_active) {
+		min_asid = min_sev_es_asid;
+		max_asid = max_sev_es_asid;

arch/x86/kvm/svm/sev.c +1 -1

 	if (min_asid > max_asid)
 		return -ENOTTY;
 

@@ -439,7 +455,7 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
 	if (vm_type == KVM_X86_SNP_VM)
 		sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
 
-	ret = sev_asid_new(sev);
+	ret = sev_asid_new(sev, vm_type);
 	if (ret)
 		goto e_no_asid;
 

arch/x86/kvm/svm/sev.c +0 -0

 >  	sev_enabled = sev_supported;
 	sev_es_enabled = sev_es_supported;

Quoted 55 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Introduce new min, max sev_es_asid and sev_snp_asid variables.

The new {min,max}_{sev_es,snp}_asid variables along with existing {min,max}_sev_asid variable simplifies partitioning of the SEV and SEV-ES+ ASID space.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
 arch/x86/kvm/svm/sev.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

arch/x86/kvm/svm/sev.c +12 -6

index dea9480b9ff6..383db1da8699 100644
@@ -85,6 +85,10 @@ static DECLARE_RWSEM(sev_deactivate_lock);
 static DEFINE_MUTEX(sev_bitmap_lock);
 unsigned int max_sev_asid;
 static unsigned int min_sev_asid;
+static unsigned int max_sev_es_asid;
+static unsigned int min_sev_es_asid;
+static unsigned int max_snp_asid;
+static unsigned int min_snp_asid;
 static unsigned long sev_me_mask;
 static unsigned int nr_asids;
 static unsigned long *sev_asid_bitmap;

@@ -172,20 +176,32 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
 	misc_cg_uncharge(type, sev->misc_cg, 1);
 }
 
-static int sev_asid_new(struct kvm_sev_info *sev)
+static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
 {
 	/*
 	 * SEV-enabled guests must use asid from min_sev_asid to max_sev_asid.
 	 * SEV-ES-enabled guest can use from 1 to min_sev_asid - 1.
-	 * Note: min ASID can end up larger than the max if basic SEV support is
-	 * effectively disabled by disallowing use of ASIDs for SEV guests.
 	 */
-	unsigned int min_asid = sev->es_active ? 1 : min_sev_asid;
-	unsigned int max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
-	unsigned int asid;
+	unsigned int min_asid, max_asid, asid;
 	bool retry = true;
 	int ret;
 
+	if (vm_type == KVM_X86_SNP_VM) {
+		min_asid = min_snp_asid;
+		max_asid = max_snp_asid;
+	} else if (sev->es_active) {
+		min_asid = min_sev_es_asid;
+		max_asid = max_sev_es_asid;

arch/x86/kvm/svm/sev.c static void sev_misc_cg_uncharge(struct kvm_sev_info *sev) · line 204

Quoted 10 lines

arch/x86/kvm/svm/sev.c +10 -0

+	} else {
+		min_asid = min_sev_asid;
+		max_asid = max_sev_asid;
+	}
+
+	/*
+	 * The min ASID can end up larger than the max if basic SEV support is
+	 * effectively disabled by disallowing use of ASIDs for SEV guests.
+	 */
+

Remove blank line.

Quoted 13 lines

arch/x86/kvm/svm/sev.c +1 -1

 	if (min_asid > max_asid)
 		return -ENOTTY;
 

@@ -439,7 +455,7 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
 	if (vm_type == KVM_X86_SNP_VM)
 		sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
 
-	ret = sev_asid_new(sev);
+	ret = sev_asid_new(sev, vm_type);
 	if (ret)
 		goto e_no_asid;
 

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3049

Quoted 5 lines

arch/x86/kvm/svm/sev.c +2 -0

@@ -3029,6 +3045,9 @@ void __init sev_hardware_setup(void)
 		goto out;
 	}
 
+	min_sev_es_asid = min_snp_asid = 1;
+	max_sev_es_asid = max_snp_asid = min_sev_asid - 1;

Should these be moved to after the min_sev_asid == 1 check ...

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3070

Quoted 10 lines

arch/x86/kvm/svm/sev.c +2 -1

+
 	/* Has the system been allocated ASIDs for SEV-ES? */
 	if (min_sev_asid == 1)
 		goto out;

@@ -3048,11 +3067,11 @@ void __init sev_hardware_setup(void)
 	if (boot_cpu_has(X86_FEATURE_SEV_ES))
 		pr_info("SEV-ES %s (ASIDs %u - %u)\n",
 			str_enabled_disabled(sev_es_supported),
-			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+			min_sev_es_asid, max_sev_es_asid);

... so that this becomes 0 and 0 if min_sev_asid == 1 ? (like before)

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3074

Quoted 5 lines

arch/x86/kvm/svm/sev.c +1 -1

 	if (boot_cpu_has(X86_FEATURE_SEV_SNP))
 		pr_info("SEV-SNP %s (ASIDs %u - %u)\n",
 			str_enabled_disabled(sev_snp_supported),
-			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+			min_snp_asid, max_snp_asid);

Ditto

Thanks,
Tom

Quoted 2 lines

arch/x86/kvm/svm/sev.c +0 -0

 >  	sev_enabled = sev_supported;
 	sev_es_enabled = sev_es_supported;

Documentation/admin-guide/kernel-parameters.txt line 2902

Quoted 9 lines · Ashish Kalra

Documentation/admin-guide/kernel-parameters.txt +9 -0

+	kvm-amd.ciphertext_hiding_nr_asids=
+			[KVM,AMD] Enables SEV-SNP CipherTextHiding feature and
+			controls show many ASIDs are available for SEV-SNP guests.
+			The ASID space is basically split into legacy SEV and
+			SEV-ES+. CipherTextHiding feature further splits the
+			SEV-ES+ ASID space into SEV-ES and SEV-SNP.
+			If the value is -1, then it is used as an auto flag
+			and splits the ASID space equally between SEV-ES and
+			SEV-SNP ASIDs.

This help text isn't great.

It doesn't come out and say what the connection between CipherTextHiding and SEV-ES+. It's also impossible to choose a good number without knowing how large the ASID space is in the first place.

Why use "-1"? Why not just take "auto" as a parameter?

It also needs to say what CipherTextHiding is in the first place and be more clear about what the tradeoffs are from enabling this.

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host reads will see constant default values (0xff).

The SEV ASID space is basically split into legacy SEV and SEV-ES+. CipherTextHiding further partitions the SEV-ES+ ASID space into SEV-ES

and SEV-SNP.

Add new module parameter to the KVM module to enable CipherTextHiding

support and a user configurable system-wide maximum SNP ASID value. If the module parameter value is -1 then the ASID space is equally divided between SEV-SNP and SEV-ES guests.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
 .../admin-guide/kernel-parameters.txt         | 10 ++++++
 arch/x86/kvm/svm/sev.c                        | 31 +++++++++++++++++++
 2 files changed, 41 insertions(+)

Documentation/admin-guide/kernel-parameters.txt +0 -0

index 1e5e76bba9da..2cddb2b5c59d 100644

Documentation/admin-guide/kernel-parameters.txt +0 -0

 	kvm-arm.mode=
 			[KVM,ARM,EARLY] Select one of KVM/arm64's modes of
 			operation.

arch/x86/kvm/svm/sev.c +8 -0

index 383db1da8699..68dcb13d98f2 100644
@@ -59,6 +59,10 @@ static bool sev_es_debug_swap_enabled = true;
 module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
 static u64 sev_supported_vmsa_features;
 
+static int ciphertext_hiding_nr_asids;
+module_param(ciphertext_hiding_nr_asids, int, 0444);
+MODULE_PARM_DESC(max_snp_asid, "  Number of ASIDs available for SEV-SNP guests when CipherTextHiding is enabled");
+
 #define AP_RESET_HOLD_NONE		0
 #define AP_RESET_HOLD_NAE_EVENT		1
 #define AP_RESET_HOLD_MSR_PROTO		2

@@ -200,6 +204,9 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
 	/*
 	 * The min ASID can end up larger than the max if basic SEV support is
 	 * effectively disabled by disallowing use of ASIDs for SEV guests.
+	 * Similarly for SEV-ES guests the min ASID can end up larger than the
+	 * max when CipherTextHiding is enabled, effectively disabling SEV-ES
+	 * support.
 	 */
 
 	if (min_asid > max_asid)

@@ -2955,6 +2962,7 @@ void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
 	struct sev_platform_init_args init_args = {0};
+	bool snp_cipher_text_hiding = false;
 	bool sev_snp_supported = false;
 	bool sev_es_supported = false;
 	bool sev_supported = false;

arch/x86/kvm/svm/sev.c +4 -0

+	}
+
 	sev_es_asid_count = min_sev_asid - 1;
 	WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
 	sev_es_supported = true;

@@ -3092,6 +3121,8 @@ void __init sev_hardware_setup(void)
 	 * Do both SNP and SEV initialization at KVM module load.
 	 */
 	init_args.probe = true;
+	if (snp_cipher_text_hiding)
+		init_args.snp_max_snp_asid = max_snp_asid;
 	sev_platform_init(&init_args);
 }
 

Quoted 8 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host reads will see constant default values (0xff).

The SEV ASID space is basically split into legacy SEV and SEV-ES+. CipherTextHiding further partitions the SEV-ES+ ASID space into SEV-ES

s/CipherTextHiding/Ciphertext hiding/

Quoted 3 lines

and SEV-SNP.

Add new module parameter to the KVM module to enable CipherTextHiding

Ditto.

Quoted 20 lines

support and a user configurable system-wide maximum SNP ASID value. If the module parameter value is -1 then the ASID space is equally divided between SEV-SNP and SEV-ES guests.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
 .../admin-guide/kernel-parameters.txt         | 10 ++++++
 arch/x86/kvm/svm/sev.c                        | 31 +++++++++++++++++++
 2 files changed, 41 insertions(+)

Documentation/admin-guide/kernel-parameters.txt +0 -0

index 1e5e76bba9da..2cddb2b5c59d 100644
@@ -2891,6 +2891,16 @@
 			(enabled). Disable by KVM if hardware lacks support
 			for NPT.
 

Documentation/admin-guide/kernel-parameters.txt line 2894

Quoted 1 line

Documentation/admin-guide/kernel-parameters.txt +1 -0

+	kvm-amd.ciphertext_hiding_nr_asids=

s/ns_asids/asids/

I'm not sure that the "nr" adds anything here.

Documentation/admin-guide/kernel-parameters.txt line 2903

Quoted 9 lines

Documentation/admin-guide/kernel-parameters.txt +9 -0

+			[KVM,AMD] Enables SEV-SNP CipherTextHiding feature and
+			controls show many ASIDs are available for SEV-SNP guests.
+			The ASID space is basically split into legacy SEV and
+			SEV-ES+. CipherTextHiding feature further splits the
+			SEV-ES+ ASID space into SEV-ES and SEV-SNP.
+			If the value is -1, then it is used as an auto flag
+			and splits the ASID space equally between SEV-ES and
+			SEV-SNP ASIDs.
+

Ditto on Dave's comments.

Quoted 37 lines

Documentation/admin-guide/kernel-parameters.txt +0 -0

 	kvm-arm.mode=
 			[KVM,ARM,EARLY] Select one of KVM/arm64's modes of
 			operation.

arch/x86/kvm/svm/sev.c +8 -0

index 383db1da8699..68dcb13d98f2 100644
@@ -59,6 +59,10 @@ static bool sev_es_debug_swap_enabled = true;
 module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
 static u64 sev_supported_vmsa_features;
 
+static int ciphertext_hiding_nr_asids;
+module_param(ciphertext_hiding_nr_asids, int, 0444);
+MODULE_PARM_DESC(max_snp_asid, "  Number of ASIDs available for SEV-SNP guests when CipherTextHiding is enabled");
+
 #define AP_RESET_HOLD_NONE		0
 #define AP_RESET_HOLD_NAE_EVENT		1
 #define AP_RESET_HOLD_MSR_PROTO		2

@@ -200,6 +204,9 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
 	/*
 	 * The min ASID can end up larger than the max if basic SEV support is
 	 * effectively disabled by disallowing use of ASIDs for SEV guests.
+	 * Similarly for SEV-ES guests the min ASID can end up larger than the
+	 * max when CipherTextHiding is enabled, effectively disabling SEV-ES
+	 * support.
 	 */
 
 	if (min_asid > max_asid)

@@ -2955,6 +2962,7 @@ void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
 	struct sev_platform_init_args init_args = {0};
+	bool snp_cipher_text_hiding = false;
 	bool sev_snp_supported = false;
 	bool sev_es_supported = false;
 	bool sev_supported = false;

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3066

Quoted 7 lines

arch/x86/kvm/svm/sev.c +4 -0

@@ -3052,6 +3060,27 @@ void __init sev_hardware_setup(void)
 	if (min_sev_asid == 1)
 		goto out;
 
+	/*
+	 * The ASID space is basically split into legacy SEV and SEV-ES+.
+	 * CipherTextHiding feature further partitions the SEV-ES+ ASID space
+	 * into ASIDs for SEV-ES and SEV-SNP guests.

I think it is already understood that the ASID space is split between SEV and SEV-ES/SEV-SNP guests. So something like this maybe?

The ciphertext hiding feature partions the joint SEV-ES/SEV-SNP ASID range into separate SEV-ES and SEV-SNP ASID ranges with teh SEV-SNP ASID range starting at 1.

Quoted 4 lines

arch/x86/kvm/svm/sev.c +4 -0

+	 */
+	if (ciphertext_hiding_nr_asids && sev_is_snp_ciphertext_hiding_supported()) {
+		/* Do sanity checks on user-defined ciphertext_hiding_nr_asids */
+		if (ciphertext_hiding_nr_asids != -1 &&

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3074

Quoted 4 lines

arch/x86/kvm/svm/sev.c +4 -0

+		    ciphertext_hiding_nr_asids >= min_sev_asid) {
+			pr_info("ciphertext_hiding_nr_asids module parameter invalid, limiting SEV-SNP ASIDs to %d\n",
+				 min_sev_asid);
+			ciphertext_hiding_nr_asids = min_sev_asid - 1;

So specifying a number greater than min_sev_asid will result in enabling ciphertext hiding and no SEV-ES guests allowed even though you report that the number is invalid?

I think the message can be worded better to convey what happens.

"Requested ciphertext hiding ASIDs (%u) exceeds minimum SEV ASID (%u), setting ciphertext hiding ASID range to the maximum value (%u)\n"

Or something a little more concise.

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3077

Quoted 3 lines

arch/x86/kvm/svm/sev.c +3 -0

+		}
+
+		min_sev_es_asid = ciphertext_hiding_nr_asids == -1 ? (min_sev_asid - 1) / 2 :

Should this be (min_sev_asid - 1) / 2 + 1 ?

Take min_sev_asid = 3, that means min_sev_es_asid would be 2 and max_snp_asid would be 1, right?

And if you set min_sev_es_asid before first you favor SEV-ES.

So should you do:

max_snp_asid = ciphertext_hiding_asids != -1 ? : (min_sev_asid - 1) / 2 + 1; min_sev_es_asid = max_snp_asid + 1;

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3081

Quoted 5 lines

arch/x86/kvm/svm/sev.c +4 -0

+				  ciphertext_hiding_nr_asids + 1;
+		max_snp_asid = min_sev_es_asid - 1;
+		snp_cipher_text_hiding = true;
+		pr_info("SEV-SNP CipherTextHiding feature support enabled\n");

"SEV-SNP ciphertext hiding enabled\n"

No need to use the CipherTextHiding nomenclature everywhere.

Thanks,
Tom

Quoted 14 lines

arch/x86/kvm/svm/sev.c +4 -0

+	}
+
 	sev_es_asid_count = min_sev_asid - 1;
 	WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
 	sev_es_supported = true;

@@ -3092,6 +3121,8 @@ void __init sev_hardware_setup(void)
 	 * Do both SNP and SEV initialization at KVM module load.
 	 */
 	init_args.probe = true;
+	if (snp_cipher_text_hiding)
+		init_args.snp_max_snp_asid = max_snp_asid;
 	sev_platform_init(&init_args);
 }
 

Hello Tom,

Quoted 5 lines · Tom Lendacky

Quoted 2 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Quoted 4 lines

The ciphertext hiding feature partions the joint SEV-ES/SEV-SNP ASID range into separate SEV-ES and SEV-SNP ASID ranges with teh SEV-SNP ASID range starting at 1.

Yes that sounds better.

Quoted 14 lines

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3074

Quoted 9 lines

arch/x86/kvm/svm/sev.c +8 -0

+	 */
+	if (ciphertext_hiding_nr_asids && sev_is_snp_ciphertext_hiding_supported()) {
+		/* Do sanity checks on user-defined ciphertext_hiding_nr_asids */
+		if (ciphertext_hiding_nr_asids != -1 &&
+		    ciphertext_hiding_nr_asids >= min_sev_asid) {
+			pr_info("ciphertext_hiding_nr_asids module parameter invalid, limiting SEV-SNP ASIDs to %d\n",
+				 min_sev_asid);
+			ciphertext_hiding_nr_asids = min_sev_asid - 1;

So specifying a number greater than min_sev_asid will result in enabling ciphertext hiding and no SEV-ES guests allowed even though you report that the number is invalid?

Well, the user specified a non-zero ciphertext_hiding_nr_asids, so the intent is to enable ciphertext hiding and therefore sanitize the user specified parameter and enable ciphertext hiding.

Quoted 8 lines · Ashish

Hello Tom,

Quoted 5 lines · Tom Lendacky

Quoted 2 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Quoted 6 lines

Quoted 4 lines

The ciphertext hiding feature partions the joint SEV-ES/SEV-SNP ASID range into separate SEV-ES and SEV-SNP ASID ranges with teh SEV-SNP ASID range starting at 1.

Yes that sounds better.

Just fix my spelling errors :)

Quoted 15 lines

Quoted 14 lines

arch/x86/kvm/svm/sev.c void __init sev_hardware_setup(void) · line 3074

Quoted 9 lines

arch/x86/kvm/svm/sev.c +8 -0

+	 */
+	if (ciphertext_hiding_nr_asids && sev_is_snp_ciphertext_hiding_supported()) {
+		/* Do sanity checks on user-defined ciphertext_hiding_nr_asids */
+		if (ciphertext_hiding_nr_asids != -1 &&
+		    ciphertext_hiding_nr_asids >= min_sev_asid) {
+			pr_info("ciphertext_hiding_nr_asids module parameter invalid, limiting SEV-SNP ASIDs to %d\n",
+				 min_sev_asid);
+			ciphertext_hiding_nr_asids = min_sev_asid - 1;

So specifying a number greater than min_sev_asid will result in enabling ciphertext hiding and no SEV-ES guests allowed even though you report that the number is invalid?

Quoted 2 lines

Well, the user specified a non-zero ciphertext_hiding_nr_asids, so the intent is to enable ciphertext hiding and therefore sanitize the user specified parameter and enable ciphertext hiding.

Should you support something like ciphertext_hiding_asids=max (similar to the 'auto' comment that Dave had) and report an error if a value is specified that exceeds min_sev_asid and not enable ciphertext hiding?

Thanks,
Tom

Quoted 1 line

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host reads will see constant default values (0xff).

The SEV ASID space is basically split into legacy SEV and SEV-ES+. CipherTextHiding further partitions the SEV-ES+ ASID space into SEV-ES and SEV-SNP.

Add new module parameter to the KVM module to enable CipherTextHiding support and a user configurable system-wide maximum SNP ASID value. If the module parameter value is -1 then the ASID space is equally divided between SEV-SNP and SEV-ES guests.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
  .../admin-guide/kernel-parameters.txt         | 10 ++++++
  arch/x86/kvm/svm/sev.c                        | 31 +++++++++++++++++++
  2 files changed, 41 insertions(+)

Documentation/admin-guide/kernel-parameters.txt +0 -0

index 1e5e76bba9da..2cddb2b5c59d 100644
@@ -2891,6 +2891,16 @@
  			(enabled). Disable by KVM if hardware lacks support
  			for NPT.

Documentation/admin-guide/kernel-parameters.txt +1 -0

+
  	kvm-arm.mode=
  			[KVM,ARM,EARLY] Select one of KVM/arm64's modes of
  			operation.

arch/x86/kvm/svm/sev.c +17 -0

index 383db1da8699..68dcb13d98f2 100644
@@ -59,6 +59,10 @@ static bool sev_es_debug_swap_enabled = true;
  module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
  static u64 sev_supported_vmsa_features;
 
+static int ciphertext_hiding_nr_asids;
+module_param(ciphertext_hiding_nr_asids, int, 0444);
+MODULE_PARM_DESC(max_snp_asid, "  Number of ASIDs available for SEV-SNP guests when CipherTextHiding is enabled");
+
  #define AP_RESET_HOLD_NONE		0
  #define AP_RESET_HOLD_NAE_EVENT		1
  #define AP_RESET_HOLD_MSR_PROTO		2

@@ -200,6 +204,9 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
  	/*
  	 * The min ASID can end up larger than the max if basic SEV support is
  	 * effectively disabled by disallowing use of ASIDs for SEV guests.
+	 * Similarly for SEV-ES guests the min ASID can end up larger than the
+	 * max when CipherTextHiding is enabled, effectively disabling SEV-ES
+	 * support.
  	 */
 
  	if (min_asid > max_asid)

@@ -2955,6 +2962,7 @@ void __init sev_hardware_setup(void)
  {
  	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
  	struct sev_platform_init_args init_args = {0};
+	bool snp_cipher_text_hiding = false;
  	bool sev_snp_supported = false;
  	bool sev_es_supported = false;
  	bool sev_supported = false;

@@ -3052,6 +3060,27 @@ void __init sev_hardware_setup(void)
  	if (min_sev_asid == 1)
  		goto out;
 
+	/*
+	 * The ASID space is basically split into legacy SEV and SEV-ES+.
+	 * CipherTextHiding feature further partitions the SEV-ES+ ASID space
+	 * into ASIDs for SEV-ES and SEV-SNP guests.
+	 */
+	if (ciphertext_hiding_nr_asids && sev_is_snp_ciphertext_hiding_supported()) {
+		/* Do sanity checks on user-defined ciphertext_hiding_nr_asids */
+		if (ciphertext_hiding_nr_asids != -1 &&
+		    ciphertext_hiding_nr_asids >= min_sev_asid) {

arch/x86/kvm/svm/sev.c +4 -0

+	}
+
  	sev_es_asid_count = min_sev_asid - 1;
  	WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
  	sev_es_supported = true;

@@ -3092,6 +3121,8 @@ void __init sev_hardware_setup(void)
  	 * Do both SNP and SEV initialization at KVM module load.
  	 */
  	init_args.probe = true;
+	if (snp_cipher_text_hiding)
+		init_args.snp_max_snp_asid = max_snp_asid;
  	sev_platform_init(&init_args);
  }
 

Quoted 33 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host reads will see constant default values (0xff).

The SEV ASID space is basically split into legacy SEV and SEV-ES+. CipherTextHiding further partitions the SEV-ES+ ASID space into SEV-ES and SEV-SNP.

Add new module parameter to the KVM module to enable CipherTextHiding support and a user configurable system-wide maximum SNP ASID value. If the module parameter value is -1 then the ASID space is equally divided between SEV-SNP and SEV-ES guests.

Suggested-by Sean Christopherson <[email protected]>

Signed-off-by Ashish Kalra <[email protected]>

---
  .../admin-guide/kernel-parameters.txt         | 10 ++++++ arch/x86/kvm/svm/sev.c                        | 31 +++++++++++++++++++

  2 files changed, 41 insertions(+)

Documentation/admin-guide/kernel-parameters.txt +0 -0

index 1e5e76bba9da..2cddb2b5c59d 100644
@@ -2891,6 +2891,16 @@

              (enabled). Disable by KVM if hardware lacks support for NPT.
  +    kvm-amd.ciphertext_hiding_nr_asids=
+            [KVM,AMD] Enables SEV-SNP CipherTextHiding feature and +            controls show many ASIDs are available for SEV-SNP guests. +            The ASID space is basically split into legacy SEV and

Quoted 5 lines

+            SEV-ES+. CipherTextHiding feature further splits the +            SEV-ES+ ASID space into SEV-ES and SEV-SNP. +            If the value is -1, then it is used as an auto flag +            and splits the ASID space equally between SEV-ES and +            SEV-SNP ASIDs.

Why in halves? 0 or max would make sense and I'd think the user wants all SEV-ES+ VMs be hidden by default so I'd name the parameter as no_hiding_nr_asids and make the default value of zero mean "every SEV-ES+ is hidden".

Or there is a downside of hiding all VMs?

Quoted 49 lines

+
      kvm-arm.mode=
              [KVM,ARM,EARLY] Select one of KVM/arm64's modes of operation.

arch/x86/kvm/svm/sev.c +7 -0

index 383db1da8699..68dcb13d98f2 100644
@@ -59,6 +59,10 @@ static bool sev_es_debug_swap_enabled = true;
   module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
   static u64 sev_supported_vmsa_features;
   +static int ciphertext_hiding_nr_asids;
+module_param(ciphertext_hiding_nr_asids, int, 0444);
+MODULE_PARM_DESC(max_snp_asid, "  Number of ASIDs available for SEV-SNP guests when CipherTextHiding is enabled");
+
   #define AP_RESET_HOLD_NONE        0
   #define AP_RESET_HOLD_NAE_EVENT        1
   #define AP_RESET_HOLD_MSR_PROTO        2

@@ -200,6 +204,9 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
       /*
        * The min ASID can end up larger than the max if basic SEV support is
        * effectively disabled by disallowing use of ASIDs for SEV guests.
+     * Similarly for SEV-ES guests the min ASID can end up larger than the
+     * max when CipherTextHiding is enabled, effectively disabling SEV-ES
+     * support.
        */
         if (min_asid > max_asid)

@@ -2955,6 +2962,7 @@ void __init sev_hardware_setup(void)
   {
       unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
       struct sev_platform_init_args init_args = {0};
+    bool snp_cipher_text_hiding = false;
       bool sev_snp_supported = false;
       bool sev_es_supported = false;
       bool sev_supported = false;

@@ -3052,6 +3060,27 @@ void __init sev_hardware_setup(void)
       if (min_sev_asid == 1)
           goto out;

  +    /*
+     * The ASID space is basically split into legacy SEV and SEV-ES+.
+     * CipherTextHiding feature further partitions the SEV-ES+ ASID space
+     * into ASIDs for SEV-ES and SEV-SNP guests.
+     */
+    if (ciphertext_hiding_nr_asids && sev_is_snp_ciphertext_hiding_supported()) {
+        /* Do sanity checks on user-defined ciphertext_hiding_nr_asids */
+        if (ciphertext_hiding_nr_asids != -1 &&
+            ciphertext_hiding_nr_asids >= min_sev_asid) {
+            pr_info("ciphertext_hiding_nr_asids module parameter invalid, limiting SEV-SNP ASIDs to %d\n", +                 min_sev_asid);

Quoted 8 lines

+            ciphertext_hiding_nr_asids = min_sev_asid - 1;
+        }
+
+        min_sev_es_asid = ciphertext_hiding_nr_asids == -1 ? (min_sev_asid - 1) / 2 :
+                  ciphertext_hiding_nr_asids + 1;
+        max_snp_asid = min_sev_es_asid - 1;
+        snp_cipher_text_hiding = true;
+        pr_info("SEV-SNP CipherTextHiding feature support enabled\n");

Can do "init_args.snp_max_snp_asid = max_snp_asid;" here (as max_snp_asid seems to not change between here and next hunk) and drop snp_cipher_text_hiding. Thanks,

Quoted 14 lines

+    }
+
      sev_es_asid_count = min_sev_asid - 1; WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count)); sev_es_supported = true;

arch/x86/kvm/svm/sev.c +2 -0

@@ -3092,6 +3121,8 @@ void __init sev_hardware_setup(void)
        * Do both SNP and SEV initialization at KVM module load.
        */
       init_args.probe = true;
+    if (snp_cipher_text_hiding)
+        init_args.snp_max_snp_asid = max_snp_asid;
       sev_platform_init(&init_args);
   }

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host will see constant default values (0xff).

Hi Ashish,

Quoted 5 lines · Ashish Kalra

From: Ashish Kalra <[email protected]>

Ciphertext hiding prevents host accesses from reading the ciphertext of SNP guest private memory. Instead of reading ciphertext, the host will see constant default values (0xff).

If I apply this on top of next-20250522, I get the following stacktrace, i.e., this assertion failure:

static int sev_write_init_ex_file_if_required(int cmd_id) {
        lockdep_assert_held(&sev_cmd_mutex);

Config attached.

Thanks,

Kim

[   34.653536] ------------[ cut here ]------------
[   34.653545] WARNING: CPU: 92 PID: 4581 at drivers/crypto/ccp/sev-dev.c:349 __sev_do_cmd_locked+0x7eb/0xb90 [ccp]
[   34.653570] Modules linked in: binfmt_misc rapl wmi_bmof kvm ast drm_client_lib drm_shmem_helper drm_kms_helper ccp(+) i2c_algo_bit i2c_piix4 k10temp i2c_smbus acpi_ipmi ipmi_si(+) ipmi_devintf ipmi_msghandler mac_hid sch_fq_codel dm_multipath drm efi_pstore nfnetlink dmi_sysfs ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 linear dm_mirror dm_region_hash dm_log ghash_clmulni_intel nvme sha512_ssse3 ahci sha1_ssse3 libahci nvme_core wmi aesni_intel [   34.653645] CPU: 92 UID: 0 PID: 4581 Comm: (udev-worker) Not tainted 6.15.0-rc7-next-20250522+ #4 PREEMPT(voluntary) 849304994a065362c1f65db9527c0b4292d5aea6
[   34.653651] Hardware name: AMD Corporation VOLCANO/VOLCANO, BIOS RVOT1005B 04/08/2025
[   34.653653] RIP: 0010:__sev_do_cmd_locked+0x7eb/0xb90 [ccp]
[   34.653661] Code: fa ff ff be ff ff ff ff 48 c7 c7 50 cd b1 c0 44 89 85 70 ff ff ff e8 c4 fe f3 f3 44 8b 85 70 ff ff ff 85 c0 0f 85 e2 fd ff ff <0f> 0b e9 db fd ff ff 48 8b 05 57 aa 12 00 8b 0d 95 82 0c f5 48 c7
[   34.653664] RSP: 0018:ff51f9b5d9f37890 EFLAGS: 00010246
[   34.653668] RAX: 0000000000000000 RBX: 0000000000000083 RCX: 0000000000000001
[   34.653671] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000246
[   34.653672] RBP: ff51f9b5d9f37940 R08: 0000000000000000 R09: 0000000000000000
[   34.653674] R10: 0000000000000001 R11: 0000000000000001 R12: ff51f9b5d9f37954
[   34.653676] R13: ff3121dada778000 R14: 0000000000000000 R15: ff3121dadb5c5028
[   34.653677] FS:  00007f0ed64488c0(0000) GS:ff3121e9b1a00000(0000) knlGS:0000000000000000
[   34.653679] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   34.653681] CR2: 00005599a0790fc8 CR3: 0000000108cd8001 CR4: 0000000000771ef0
[   34.653684] PKRU: 55555554
[   34.653686] Call Trace:
[   34.653687]  <TASK>
[   34.653701]  sev_get_api_version+0xb2/0x2b0 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653714]  ? __pfx_sp_mod_init+0x10/0x10 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653727]  sev_pci_init+0x4a/0x320 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653733]  ? preempt_count_sub+0x50/0x80
[   34.653741]  ? _raw_write_unlock_irqrestore+0x53/0x90
[   34.653748]  ? __pfx_sp_mod_init+0x10/0x10 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653756]  psp_pci_init+0x2f/0x50 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653763]  sp_mod_init+0x32/0xff0 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.653770]  do_one_initcall+0x5f/0x3c0
[   34.653774]  ? __kmalloc_cache_noprof+0x331/0x430
[   34.653784]  do_init_module+0x68/0x260
[   34.653789]  load_module+0x22ea/0x2410
[   34.653803]  ? kernel_read_file+0x2a4/0x320
[   34.653811]  init_module_from_file+0x96/0xd0
[   34.653815]  ? init_module_from_file+0x96/0xd0
[   34.653825]  idempotent_init_module+0x117/0x330
[   34.653836]  __x64_sys_finit_module+0x6f/0xe0
[   34.653841]  x64_sys_call+0x1f9e/0x20c0
[   34.653844]  do_syscall_64+0x8d/0x2d0
[   34.653849]  ? local_clock_noinstr+0x12/0xc0
[   34.653855]  ? rcu_read_unlock+0x1b/0x70
[   34.653860]  ? sched_clock_noinstr+0xd/0x20
[   34.653864]  ? local_clock_noinstr+0x12/0xc0
[   34.653869]  ? exc_page_fault+0x95/0x230
[   34.653876]  ? irqentry_exit_to_user_mode+0xb1/0x1e0
[   34.653880]  ? irqentry_exit+0x6f/0xa0
[   34.653882]  ? exc_page_fault+0xb4/0x230
[   34.653886]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   34.653888] RIP: 0033:0x7f0ed632725d
[   34.653892] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b bb 0d 00 f7 d8 64 89 01 48
[   34.653894] RSP: 002b:00007ffe599733b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   34.653897] RAX: ffffffffffffffda RBX: 00005599a07b4370 RCX: 00007f0ed632725d
[   34.653899] RDX: 0000000000000000 RSI: 00007f0ed662507d RDI: 0000000000000022
[   34.653901] RBP: 00007ffe59973470 R08: 0000000000000040 R09: 00007ffe59973420
[   34.653902] R10: 00007f0ed6403b20 R11: 0000000000000246 R12: 00007f0ed662507d
[   34.653903] R13: 0000000000020000 R14: 00005599a07b6020 R15: 00005599a07b9230
[   34.653913]  </TASK>
[   34.653914] irq event stamp: 211387
[   34.653916] hardirqs last  enabled at (211393): [<ffffffffb37a6786>] __up_console_sem+0x86/0x90
[   34.653922] hardirqs last disabled at (211398): [<ffffffffb37a676b>] __up_console_sem+0x6b/0x90
[   34.653923] softirqs last  enabled at (209856): [<ffffffffb36e364f>] handle_softirqs+0x32f/0x410
[   34.653928] softirqs last disabled at (209833): [<ffffffffb36e3800>] __irq_exit_rcu+0xc0/0xf0
[   34.653932] ---[ end trace 0000000000000000 ]---
[   34.654388] ------------[ cut here ]------------
[   34.654391] WARNING: CPU: 92 PID: 4581 at drivers/crypto/ccp/sev-dev.c:349 __sev_do_cmd_locked+0x7eb/0xb90 [ccp]
[   34.654396] Modules linked in: binfmt_misc rapl wmi_bmof kvm ast drm_client_lib drm_shmem_helper drm_kms_helper ccp(+) i2c_algo_bit i2c_piix4 k10temp i2c_smbus acpi_ipmi ipmi_si(+) ipmi_devintf ipmi_msghandler mac_hid sch_fq_codel dm_multipath drm efi_pstore nfnetlink dmi_sysfs ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 linear dm_mirror dm_region_hash dm_log ghash_clmulni_intel nvme sha512_ssse3 ahci sha1_ssse3 libahci nvme_core wmi aesni_intel [   34.654430] CPU: 92 UID: 0 PID: 4581 Comm: (udev-worker) Tainted: G        W           6.15.0-rc7-next-20250522+ #4 PREEMPT(voluntary)  849304994a065362c1f65db9527c0b4292d5aea6
[   34.654433] Tainted: [W]=WARN
[   34.654435] RIP: 0010:__sev_do_cmd_locked+0x7eb/0xb90 [ccp]
[   34.654439] Code: fa ff ff be ff ff ff ff 48 c7 c7 50 cd b1 c0 44 89 85 70 ff ff ff e8 c4 fe f3 f3 44 8b 85 70 ff ff ff 85 c0 0f 85 e2 fd ff ff <0f> 0b e9 db fd ff ff 48 8b 05 57 aa 12 00 8b 0d 95 82 0c f5 48 c7
[   34.654440] RSP: 0018:ff51f9b5d9f37890 EFLAGS: 00010246
[   34.654442] RAX: 0000000000000000 RBX: 00000000000000ce RCX: 0000000000000001
[   34.654443] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000246
[   34.654443] RBP: ff51f9b5d9f37940 R08: 0000000000000000 R09: 0000000000000000
[   34.654444] R10: 0000000000000001 R11: 0000000000000001 R12: ff51f9b5d9f37968
[   34.654445] R13: ff3121dada778000 R14: 0000000000000000 R15: ff3121dadb5c5028
[   34.654446] FS:  00007f0ed64488c0(0000) GS:ff3121e9b1a00000(0000) knlGS:0000000000000000
[   34.654447] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   34.654448] CR2: 00005599a0790fc8 CR3: 0000000108cd8001 CR4: 0000000000771ef0
[   34.654449] PKRU: 55555554
[   34.654450] Call Trace:
[   34.654451]  <TASK>
[   34.654457]  sev_get_api_version+0x1e6/0x2b0 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654463]  ? __pfx_sp_mod_init+0x10/0x10 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654469]  sev_pci_init+0x4a/0x320 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654473]  ? preempt_count_sub+0x50/0x80
[   34.654475]  ? _raw_write_unlock_irqrestore+0x53/0x90
[   34.654477]  ? __pfx_sp_mod_init+0x10/0x10 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654482]  psp_pci_init+0x2f/0x50 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654487]  sp_mod_init+0x32/0xff0 [ccp 3cf3cbacf97e77e53be58eab8d4f5347a13f205d]
[   34.654491]  do_one_initcall+0x5f/0x3c0
[   34.654493]  ? __kmalloc_cache_noprof+0x331/0x430
[   34.654498]  do_init_module+0x68/0x260
[   34.654500]  load_module+0x22ea/0x2410
[   34.654509]  ? kernel_read_file+0x2a4/0x320
[   34.654513]  init_module_from_file+0x96/0xd0
[   34.654515]  ? init_module_from_file+0x96/0xd0
[   34.654522]  idempotent_init_module+0x117/0x330
[   34.654530]  __x64_sys_finit_module+0x6f/0xe0
[   34.654532]  x64_sys_call+0x1f9e/0x20c0
[   34.654534]  do_syscall_64+0x8d/0x2d0
[   34.654536]  ? local_clock_noinstr+0x12/0xc0
[   34.654539]  ? rcu_read_unlock+0x1b/0x70
[   34.654541]  ? sched_clock_noinstr+0xd/0x20
[   34.654544]  ? local_clock_noinstr+0x12/0xc0
[   34.654547]  ? exc_page_fault+0x95/0x230
[   34.654551]  ? irqentry_exit_to_user_mode+0xb1/0x1e0
[   34.654553]  ? irqentry_exit+0x6f/0xa0
[   34.654555]  ? exc_page_fault+0xb4/0x230
[   34.654558]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   34.654559] RIP: 0033:0x7f0ed632725d
[   34.654560] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b bb 0d 00 f7 d8 64 89 01 48
[   34.654561] RSP: 002b:00007ffe599733b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   34.654563] RAX: ffffffffffffffda RBX: 00005599a07b4370 RCX: 00007f0ed632725d
[   34.654564] RDX: 0000000000000000 RSI: 00007f0ed662507d RDI: 0000000000000022
[   34.654565] RBP: 00007ffe59973470 R08: 0000000000000040 R09: 00007ffe59973420
[   34.654566] R10: 00007f0ed6403b20 R11: 0000000000000246 R12: 00007f0ed662507d
[   34.654566] R13: 0000000000020000 R14: 00005599a07b6020 R15: 00005599a07b9230
[   34.654572]  </TASK>
[   34.654573] irq event stamp: 212111
[   34.654574] hardirqs last  enabled at (212117): [<ffffffffb37a6786>] __up_console_sem+0x86/0x90
[   34.654576] hardirqs last disabled at (212122): [<ffffffffb37a676b>] __up_console_sem+0x6b/0x90
[   34.654577] softirqs last  enabled at (209856): [<ffffffffb36e364f>] handle_softirqs+0x32f/0x410
[   34.654579] softirqs last disabled at (209833): [<ffffffffb36e3800>] __irq_exit_rcu+0xc0/0xf0
[   34.654581] ---[ end trace 0000000000000000 ]---