[PATCH v4 29/34] KVM: SVM: Set the encryption mask for the SVM host save area

From: Tom Lendacky
Date: Tue Nov 17 2020 - 12:12:12 EST


From: Tom Lendacky <thomas.lendacky@xxxxxxx>

The SVM host save area is used to restore some host state on VMEXIT of an
SEV-ES guest. After allocating the save area, clear it and add the
encryption mask to the SVM host save area physical address that is
programmed into the VM_HSAVE_PA MSR.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
arch/x86/kvm/svm/sev.c | 1 -
arch/x86/kvm/svm/svm.c | 3 ++-
arch/x86/kvm/svm/svm.h | 2 ++
3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 486c5609fa25..4797a6768eaf 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -32,7 +32,6 @@ unsigned int max_sev_asid;
static unsigned int min_sev_asid;
static unsigned long *sev_asid_bitmap;
static unsigned long *sev_reclaim_asid_bitmap;
-#define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)

struct enc_region {
struct list_head list;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index bb6b624c0d12..99869d781b98 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -498,7 +498,7 @@ static int svm_hardware_enable(void)

wrmsrl(MSR_EFER, efer | EFER_SVME);

- wrmsrl(MSR_VM_HSAVE_PA, page_to_pfn(sd->save_area) << PAGE_SHIFT);
+ wrmsrl(MSR_VM_HSAVE_PA, __sme_page_pa(sd->save_area));

if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
wrmsrl(MSR_AMD64_TSC_RATIO, TSC_RATIO_DEFAULT);
@@ -566,6 +566,7 @@ static int svm_cpu_init(int cpu)
sd->save_area = alloc_page(GFP_KERNEL);
if (!sd->save_area)
goto free_cpu_data;
+ clear_page(page_address(sd->save_area));

if (svm_sev_enabled()) {
sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1,
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 4529c9487c4a..95be2ba08a01 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -21,6 +21,8 @@

#include <asm/svm.h>

+#define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
+
static const u32 host_save_user_msrs[] = {
#ifdef CONFIG_X86_64
MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE,
--
2.28.0