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vfio/type1: Initialize resv_msi_base

PATCH In review Joerg Roedel 4 participants 4 messages Oct 15, 2019 – Oct 18, 2019

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KVM VFIO driver
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Joerg Roedel

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#0 lore raw

PATCH 1/1 vfio/type1: Initialize resv_msi_base

From: Joerg Roedel <[email protected]>

After enabling CONFIG_IOMMU_DMA on X86 a new warning appears when compiling vfio:

drivers/vfio/vfio_iommu_type1.c: In function ‘vfio_iommu_type1_attach_group’:
drivers/vfio/vfio_iommu_type1.c:1827:7: warning: ‘resv_msi_base’ may be used uninitialized in this function [-Wmaybe-uninitialized]
ret = iommu_get_msi_cookie(domain->domain, resv_msi_base); ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The warning is a false positive, because the call to iommu_get_msi_cookie() only happens when vfio_iommu_has_sw_msi() returned true. And that only happens when it also set resv_msi_base.

But initialize the variable anyway to get rid of the warning.

Signed-off-by Joerg Roedel <[email protected]>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/vfio/vfio_iommu_type1.c +1 -1
index 96fddc1dafc3..d864277ea16f 100644
@@ -1658,7 +1658,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	struct bus_type *bus = NULL;
 	int ret;
 	bool resv_msi, msi_remap;
-	phys_addr_t resv_msi_base;
+	phys_addr_t resv_msi_base = 0;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
 	LIST_HEAD(group_resv_regions);
Signature · 1 line
2.16.4
Reviewed-by on v1 1/1
#1 lore raw

Hi Joerg,

Quoted 27 lines · Joerg Roedel

From: Joerg Roedel <[email protected]>

After enabling CONFIG_IOMMU_DMA on X86 a new warning appears when compiling vfio:

drivers/vfio/vfio_iommu_type1.c: In function ‘vfio_iommu_type1_attach_group’:
drivers/vfio/vfio_iommu_type1.c:1827:7: warning: ‘resv_msi_base’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
   ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The warning is a false positive, because the call to iommu_get_msi_cookie() only happens when vfio_iommu_has_sw_msi() returned true. And that only happens when it also set resv_msi_base.

But initialize the variable anyway to get rid of the warning.

Signed-off-by Joerg Roedel <[email protected]>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/vfio/vfio_iommu_type1.c +0 -0
index 96fddc1dafc3..d864277ea16f 100644

drivers/vfio/vfio_iommu_type1.c static int vfio_iommu_type1_attach_group(void *iommu_data, · line 1664

Quoted 8 lines
drivers/vfio/vfio_iommu_type1.c +1 -1
@@ -1658,7 +1658,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	struct bus_type *bus = NULL;
 	int ret;
 	bool resv_msi, msi_remap;
-	phys_addr_t resv_msi_base;
+	phys_addr_t resv_msi_base = 0;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
 	LIST_HEAD(group_resv_regions);
Reviewed-by Eric Auger <[email protected]>

Thanks

Eric

Reviewed-by on v1 1/1
#2 lore raw
In reply to Joerg Roedel
Quoted 26 lines · On Tue, 15 Oct 2019 17:16:50 +0200 Joerg Roedel <[email protected]> wrote:

From: Joerg Roedel <[email protected]>

After enabling CONFIG_IOMMU_DMA on X86 a new warning appears when compiling vfio:

drivers/vfio/vfio_iommu_type1.c: In function ‘vfio_iommu_type1_attach_group’:
drivers/vfio/vfio_iommu_type1.c:1827:7: warning: ‘resv_msi_base’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
   ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The warning is a false positive, because the call to iommu_get_msi_cookie() only happens when vfio_iommu_has_sw_msi() returned true. And that only happens when it also set resv_msi_base.

But initialize the variable anyway to get rid of the warning.

Signed-off-by Joerg Roedel <[email protected]>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/vfio/vfio_iommu_type1.c +0 -0
index 96fddc1dafc3..d864277ea16f 100644

drivers/vfio/vfio_iommu_type1.c static int vfio_iommu_type1_attach_group(void *iommu_data, · line 1664

Quoted 8 lines
drivers/vfio/vfio_iommu_type1.c +1 -1
@@ -1658,7 +1658,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	struct bus_type *bus = NULL;
 	int ret;
 	bool resv_msi, msi_remap;
-	phys_addr_t resv_msi_base;
+	phys_addr_t resv_msi_base = 0;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
 	LIST_HEAD(group_resv_regions);
Reviewed-by Cornelia Huck <[email protected]>
#3 lore raw
In reply to Joerg Roedel
Quoted 26 lines · On Tue, 15 Oct 2019 17:16:50 +0200 Joerg Roedel <[email protected]> wrote:

From: Joerg Roedel <[email protected]>

After enabling CONFIG_IOMMU_DMA on X86 a new warning appears when compiling vfio:

drivers/vfio/vfio_iommu_type1.c: In function ‘vfio_iommu_type1_attach_group’:
drivers/vfio/vfio_iommu_type1.c:1827:7: warning: ‘resv_msi_base’ may be used uninitialized in this function [-Wmaybe-uninitialized]

   ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
   ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The warning is a false positive, because the call to iommu_get_msi_cookie() only happens when vfio_iommu_has_sw_msi() returned true. And that only happens when it also set resv_msi_base.

But initialize the variable anyway to get rid of the warning.

Signed-off-by Joerg Roedel <[email protected]>
---
 drivers/vfio/vfio_iommu_type1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/vfio/vfio_iommu_type1.c +0 -0
index 96fddc1dafc3..d864277ea16f 100644

drivers/vfio/vfio_iommu_type1.c static int vfio_iommu_type1_attach_group(void *iommu_data, · line 1664

Quoted 8 lines
drivers/vfio/vfio_iommu_type1.c +1 -1
@@ -1658,7 +1658,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	struct bus_type *bus = NULL;
 	int ret;
 	bool resv_msi, msi_remap;
-	phys_addr_t resv_msi_base;
+	phys_addr_t resv_msi_base = 0;
 	struct iommu_domain_geometry geo;
 	LIST_HEAD(iova_copy);
 	LIST_HEAD(group_resv_regions);

Thanks Joerg! Added to vfio for-linus branch with Connie and Eric's reviews for v5.4. Thanks,

Alex