linux-kernel - [RFC PATCH v2 28/33] KVM: SVM: Set the encryption mask for the SVM host save area

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Message-Id: <36826ae2ddedc0c2ce71cdbf516b1bf74fe343ac.1601658176.git.thomas.lendacky@amd.com>
Date:   Fri,  2 Oct 2020 12:02:52 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Brijesh Singh <brijesh.singh@....com>
Subject: [RFC PATCH v2 28/33] KVM: SVM: Set the encryption mask for the SVM host save area

From: Tom Lendacky <thomas.lendacky@....com>

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@....com>
---
 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 d30ceac85f88..4673bed1c923 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -31,7 +31,6 @@ 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 69ccffd0aef0..ff8f21ef2edb 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -478,7 +478,7 @@ 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);
@@ -546,6 +546,7 @@ 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 0d011f68064c..75733163294f 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