From: Ashish Kalra <[email protected]>
Implement a workaround for an SNP erratum where the CPU will incorrectly
signal an RMP violation #PF if a hugepage (2mb or 1gb) collides with the
RMP entry of the VMSAVE target page.
When SEV-SNP is globally enabled, the CPU marks the VMSAVE target page
as "InUse" while the VMSAVE instruction is executing. If another
CPU writes to a different page in the same 2MB region while the VMSAVE
is executing, the CPU will throw an RMP violation #PF.
Use the snp safe generic allocator for allocating the VMSA target
page which will ensure that the page returned is not a hugepage, as it
is already being used for the allocating the VMCB, VMSA and AVIC backing
page.
Co-developed-by: Marc Orr <[email protected]>
Signed-off-by: Marc Orr <[email protected]>
Reported-by: Alper Gun <[email protected]>
Signed-off-by: Ashish Kalra <[email protected]>
Signed-off-by: Michael Roth <[email protected]>
---
arch/x86/kvm/svm/svm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 543261c87eb3..1d4a723d5def 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -653,7 +653,7 @@ static int svm_cpu_init(int cpu)
int ret = -ENOMEM;
memset(sd, 0, sizeof(struct svm_cpu_data));
- sd->save_area = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ sd->save_area = snp_safe_alloc_page(NULL);
if (!sd->save_area)
return ret;
--
2.25.1