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kvm: svm: Add initial GHCB protocol version 2 support

PATCH Superseded Joerg Roedel 3 participants 6 messages Jul 13, 2021

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x86 KVM KVM x86

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Joerg Roedel

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#0 lore raw

cover kvm: svm: Add initial GHCB protocol version 2 support

From: Joerg Roedel <[email protected]>

Hi,

here is a small set of patches which I took from the pending SEV-SNP patch-sets to enable basic support for GHCB protocol version 2.

When SEV-SNP is not supported, only two new MSR protocol VMGEXIT calls need to be supported:

- MSR-based AP-reset-hold
- MSR-based HV-feature-request

These calls are implemented by here and then the protocol is lifted to version 2.

This is submitted separately because the MSR-based AP-reset-hold call is required to support kexec/kdump in SEV-ES guests.

Regards,

Joerg

Brijesh Singh (2):
KVM: SVM: Add support for Hypervisor Feature support MSR protocol
KVM: SVM: Increase supported GHCB protocol version

Tom Lendacky (1):
KVM: SVM: Add support to handle AP reset MSR protocol

 arch/x86/include/asm/sev-common.h |  5 +++
 arch/x86/include/uapi/asm/svm.h   |  1 +
 arch/x86/kvm/svm/sev.c            | 63 +++++++++++++++++++++++++++----
 arch/x86/kvm/svm/svm.h            |  4 +-
 4 files changed, 64 insertions(+), 9 deletions(-)

base-commit: e73f0f0ee7541171d89f2e2491130c7771ba58d3

Signature · 1 line
2.31.1
author
#1 lore raw

PATCH 1/3 KVM: SVM: Add support to handle AP reset MSR protocol

From: Tom Lendacky <[email protected]>

Add support for AP Reset Hold being invoked using the GHCB MSR protocol, available in version 2 of the GHCB specification.

Signed-off-by Tom Lendacky <[email protected]>
Signed-off-by Brijesh Singh <[email protected]>
Signed-off-by Joerg Roedel <[email protected]>
---
 arch/x86/include/asm/sev-common.h |  1 +
 arch/x86/kvm/svm/sev.c            | 51 ++++++++++++++++++++++++++-----
 arch/x86/kvm/svm/svm.h            |  1 +
 3 files changed, 45 insertions(+), 8 deletions(-)
arch/x86/include/asm/sev-common.h +1 -0
index 2cef6c5a52c2..dda34ecac5c0 100644
@@ -11,6 +11,7 @@
 #define GHCB_MSR_INFO_POS		0
 #define GHCB_DATA_LOW			12
 #define GHCB_MSR_INFO_MASK		(BIT_ULL(GHCB_DATA_LOW) - 1)
+#define GHCB_DATA_MASK			GENMASK_ULL(51, 0)
 
 #define GHCB_DATA(v)			\
 	(((unsigned long)(v) & ~GHCB_MSR_INFO_MASK) >> GHCB_DATA_LOW)
arch/x86/kvm/svm/sev.c +43 -8

80 lines not on this page · raw message

arch/x86/kvm/svm/svm.h +1 -0
index f89b623bb591..b21b9df54121 100644
@@ -187,6 +187,7 @@ struct vcpu_svm {
 	struct ghcb *ghcb;
 	struct kvm_host_map ghcb_map;
 	bool received_first_sipi;
+	unsigned int ap_reset_hold_type;
 
 	/* SEV-ES scratch area support */
 	void *ghcb_sa;
Signature · 1 line
2.31.1
author
#2 lore raw

PATCH 2/3 KVM: SVM: Add support for Hypervisor Feature support MSR protocol

In reply to Joerg Roedel

From: Brijesh Singh <[email protected]>

Version 2 of the GHCB specification introduced advertisement of features that are supported by the Hypervisor.

Signed-off-by Brijesh Singh <[email protected]>
Signed-off-by Joerg Roedel <[email protected]>
---
 arch/x86/include/asm/sev-common.h |  4 ++++
 arch/x86/include/uapi/asm/svm.h   |  1 +
 arch/x86/kvm/svm/sev.c            | 12 ++++++++++++
 arch/x86/kvm/svm/svm.h            |  1 +
 4 files changed, 18 insertions(+)
arch/x86/include/asm/sev-common.h +4 -0
index dda34ecac5c0..0374f5687fc0 100644
@@ -60,6 +60,10 @@
 #define GHCB_MSR_HV_FT_REQ			0x080
 #define GHCB_MSR_HV_FT_RESP			0x081
 
+/* GHCB Hypervisor Feature Request/Response */
+#define GHCB_MSR_HV_FT_REQ			0x080
+#define GHCB_MSR_HV_FT_RESP			0x081
+
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
arch/x86/include/uapi/asm/svm.h +1 -0
index efa969325ede..fbb6f8d27a80 100644
@@ -108,6 +108,7 @@
 #define SVM_VMGEXIT_AP_JUMP_TABLE		0x80000005
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
+#define SVM_VMGEXIT_HV_FT			0x8000fffd
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
 /* Exit code reserved for hypervisor/software use */
arch/x86/kvm/svm/sev.c +12 -0
index 0ec88b349799..8121b335651c 100644
@@ -2182,6 +2182,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 	case SVM_VMGEXIT_AP_HLT_LOOP:
 	case SVM_VMGEXIT_AP_JUMP_TABLE:
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
+	case SVM_VMGEXIT_HV_FT:
 		break;
 	default:
 		goto vmgexit_err;

@@ -2434,6 +2435,11 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 				  GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
 		break;
 	}
+	case GHCB_MSR_HV_FT_REQ: {
+		set_ghcb_msr_bits(svm, GHCB_HV_FT_SUPPORTED, GHCB_DATA_MASK, GHCB_DATA_LOW);
+		set_ghcb_msr_bits(svm, GHCB_MSR_HV_FT_RESP, GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+		break;
+	}
 	case GHCB_MSR_TERM_REQ: {
 		u64 reason_set, reason_code;
 

@@ -2549,6 +2555,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		ret = 1;
 		break;
 	}
+	case SVM_VMGEXIT_HV_FT: {
+		ghcb_set_sw_exit_info_2(ghcb, GHCB_HV_FT_SUPPORTED);
+
+		ret = 1;
+		break;
+	}
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
arch/x86/kvm/svm/svm.h +1 -0
index b21b9df54121..77379e1442cc 100644
@@ -546,6 +546,7 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu);
 #define GHCB_VERSION_MAX	1ULL
 #define GHCB_VERSION_MIN	1ULL
 
+#define GHCB_HV_FT_SUPPORTED	0
 
 extern unsigned int max_sev_asid;
Signature · 1 line
2.31.1
#3 lore raw

Re: [PATCH 2/3] KVM: SVM: Add support for Hypervisor Feature support MSR protocol

Quoted 19 lines · Joerg Roedel

From: Brijesh Singh <[email protected]>

Version 2 of the GHCB specification introduced advertisement of features that are supported by the Hypervisor.

Signed-off-by Brijesh Singh <[email protected]>
Signed-off-by Joerg Roedel <[email protected]>
---
 arch/x86/include/asm/sev-common.h |  4 ++++
 arch/x86/include/uapi/asm/svm.h   |  1 +
 arch/x86/kvm/svm/sev.c            | 12 ++++++++++++
 arch/x86/kvm/svm/svm.h            |  1 +
 4 files changed, 18 insertions(+)
arch/x86/include/asm/sev-common.h +0 -0
index dda34ecac5c0..0374f5687fc0 100644

arch/x86/include/asm/sev-common.h line 66

Quoted 7 lines
arch/x86/include/asm/sev-common.h +4 -0
@@ -60,6 +60,10 @@
 #define GHCB_MSR_HV_FT_REQ			0x080
 #define GHCB_MSR_HV_FT_RESP			0x081
 
+/* GHCB Hypervisor Feature Request/Response */
+#define GHCB_MSR_HV_FT_REQ			0x080
+#define GHCB_MSR_HV_FT_RESP			0x081
+

Looks like some of these definitions are already present, since the new lines are the same as the lines above it.

Thanks,
Tom

Quoted 65 lines
arch/x86/include/asm/sev-common.h +0 -0
 #define GHCB_MSR_TERM_REQ		0x100
 #define GHCB_MSR_TERM_REASON_SET_POS	12
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
arch/x86/include/uapi/asm/svm.h +1 -0
index efa969325ede..fbb6f8d27a80 100644
@@ -108,6 +108,7 @@
 #define SVM_VMGEXIT_AP_JUMP_TABLE		0x80000005
 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE		0
 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE		1
+#define SVM_VMGEXIT_HV_FT			0x8000fffd
 #define SVM_VMGEXIT_UNSUPPORTED_EVENT		0x8000ffff
 
 /* Exit code reserved for hypervisor/software use */
arch/x86/kvm/svm/sev.c +12 -0
index 0ec88b349799..8121b335651c 100644
@@ -2182,6 +2182,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 	case SVM_VMGEXIT_AP_HLT_LOOP:
 	case SVM_VMGEXIT_AP_JUMP_TABLE:
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
+	case SVM_VMGEXIT_HV_FT:
 		break;
 	default:
 		goto vmgexit_err;

@@ -2434,6 +2435,11 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
 				  GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
 		break;
 	}
+	case GHCB_MSR_HV_FT_REQ: {
+		set_ghcb_msr_bits(svm, GHCB_HV_FT_SUPPORTED, GHCB_DATA_MASK, GHCB_DATA_LOW);
+		set_ghcb_msr_bits(svm, GHCB_MSR_HV_FT_RESP, GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+		break;
+	}
 	case GHCB_MSR_TERM_REQ: {
 		u64 reason_set, reason_code;
 

@@ -2549,6 +2555,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
 		ret = 1;
 		break;
 	}
+	case SVM_VMGEXIT_HV_FT: {
+		ghcb_set_sw_exit_info_2(ghcb, GHCB_HV_FT_SUPPORTED);
+
+		ret = 1;
+		break;
+	}
 	case SVM_VMGEXIT_UNSUPPORTED_EVENT:
 		vcpu_unimpl(vcpu,
 			    "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
arch/x86/kvm/svm/svm.h +1 -0
index b21b9df54121..77379e1442cc 100644
@@ -546,6 +546,7 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu);
 #define GHCB_VERSION_MAX	1ULL
 #define GHCB_VERSION_MIN	1ULL
 
+#define GHCB_HV_FT_SUPPORTED	0
 
 extern unsigned int max_sev_asid;
#4 lore raw

Re: [PATCH 2/3] KVM: SVM: Add support for Hypervisor Feature support MSR protocol

Quoted 11 lines · Tom Lendacky

arch/x86/include/asm/sev-common.h line 66

Quoted 7 lines · Joerg Roedel

#define GHCB_MSR_HV_FT_REQ 0x080
#define GHCB_MSR_HV_FT_RESP 0x081

arch/x86/include/asm/sev-common.h +4 -0
+/* GHCB Hypervisor Feature Request/Response */
+#define GHCB_MSR_HV_FT_REQ			0x080
+#define GHCB_MSR_HV_FT_RESP			0x081
+

Looks like some of these definitions are already present, since the new lines are the same as the lines above it.

Right, that is a rebasing artifact. Thanks for spotting it, I fix that up in the next version.

Regards,

Joerg

author
#5 lore raw

PATCH 3/3 KVM: SVM: Increase supported GHCB protocol version

In reply to Joerg Roedel

From: Brijesh Singh <[email protected]>

Now that KVM has basic support for version 2 of the GHCB specification, bump the maximum supported protocol version. The SNP specific functions are still missing, but those are only required when the Hypervisor supports running SNP guests.

Signed-off-by Brijesh Singh <[email protected]>
Signed-off-by Joerg Roedel <[email protected]>
---
 arch/x86/kvm/svm/svm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kvm/svm/svm.h +1 -1
index 77379e1442cc..9adf123e0db2 100644
@@ -543,7 +543,7 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu);
 
 /* sev.c */
 
-#define GHCB_VERSION_MAX	1ULL
+#define GHCB_VERSION_MAX	2ULL
 #define GHCB_VERSION_MIN	1ULL
 
 #define GHCB_HV_FT_SUPPORTED	0
Signature · 1 line
2.31.1