FAILED: patch "[PATCH] KVM: SEV: Track the GPA of the guest-controlled VMSA used for" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] KVM: SEV: Track the GPA of the guest-controlled VMSA used for" failed to apply to 6.12-stable tree

[gregkh]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 42a39ad5d592aec87a70527a4e694f6210694482
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026083106-utensil-mangy-28f5@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 42a39ad5d592aec87a70527a4e694f6210694482 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc@google.com>
Date: Thu, 9 Jul 2026 13:49:31 -0700
Subject: [PATCH] KVM: SEV: Track the GPA of the guest-controlled VMSA used for
 SNP guests

Track the GPA of the guest-provided VMSA used after AP_CREATION events when
running SNP guests, instead of simply tracking whether or not the vCPU is
using a guest-provided VMSA.  KVM needs to know the GPA of the VMSA that's
actively being used so that it can react to MMU invalidation events, i.e.
so that KVM can drop the VMSA if its backing guest_memfd page is punched
out of existence.

Opportunistically rename snp_vmsa_gpa to clarify that it tracks the pending
VMSA GPA, whereas snp_guest_vmsa_gpa now tracks the in-use VMSA GPA.

Note!  Take care to track the GPA, not the GFN, as VALID_PAGE() won't
behave correctly if an invalid GFN is converted to a GPA for checking.

Note #2!  Keep snp_has_guest_vmsa so that switching to a guest-provided
VMSA is sticky, even if the guest-provided VMSA becomes invalid.

No functional change intended.

Cc: stable@vger.kernel.org # 6.12.x
Reviewed-by: Michael Roth <michael.roth@amd.com>
Link: https://patch.msgid.link/20260709204948.1988414-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 74fb15551e83..827f5dc06102 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4003,6 +4003,7 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 
 	/* Clear use of the VMSA */
 	svm->vmcb->control.vmsa_pa = INVALID_PAGE;
+	svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE;
 
 	/*
 	 * When replacing the VMSA during SEV-SNP AP creation,
@@ -4010,11 +4011,11 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 	 */
 	vmcb_mark_all_dirty(svm->vmcb);
 
-	if (!VALID_PAGE(svm->sev_es.snp_vmsa_gpa))
+	if (!VALID_PAGE(svm->sev_es.snp_pending_vmsa_gpa))
 		return;
 
-	gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
-	svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+	gfn = gpa_to_gfn(svm->sev_es.snp_pending_vmsa_gpa);
+	svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
 
 	slot = gfn_to_memslot(vcpu->kvm, gfn);
 	if (!slot)
@@ -4039,6 +4040,7 @@ static void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 	svm->sev_es.snp_has_guest_vmsa = true;
 
 	/* Use the new VMSA */
+	svm->sev_es.snp_guest_vmsa_gpa = gfn_to_gpa(gfn);
 	svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);
 
 	/* Mark the vCPU as runnable */
@@ -4105,10 +4107,10 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 			return -EINVAL;
 		}
 
-		target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2;
+		target_svm->sev_es.snp_pending_vmsa_gpa = svm->vmcb->control.exit_info_2;
 		break;
 	case SVM_VMGEXIT_AP_DESTROY:
-		target_svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+		target_svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
 		break;
 	default:
 		vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n",
@@ -4791,6 +4793,8 @@ int sev_vcpu_create(struct kvm_vcpu *vcpu)
 		return -ENOMEM;
 
 	svm->sev_es.vmsa = page_address(vmsa_page);
+	svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
+	svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE;
 
 	vcpu->arch.guest_tsc_protected = snp_is_secure_tsc_enabled(vcpu->kvm);
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 716be21fba33..d077783c287e 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -271,7 +271,8 @@ struct vcpu_sev_es_state {
 	u64 ghcb_registered_gpa;
 
 	struct mutex snp_vmsa_mutex; /* Used to handle concurrent updates of VMSA. */
-	gpa_t snp_vmsa_gpa;
+	gpa_t snp_pending_vmsa_gpa;
+	gpa_t snp_guest_vmsa_gpa;
 	bool snp_ap_waiting_for_reset;
 	bool snp_has_guest_vmsa;
 };

[PATCH 6.12.y 1/6] KVM: SVM: Mark VMCB dirty before processing incoming snp_vmsa_gpa

[Sasha Levin]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit e268beee4a25ce58807a96253e95e96c2e3a5c1a ]

Mark the VMCB dirty, i.e. zero control.clean, prior to handling the new
VMSA.  Nothing in the VALID_PAGE() case touches control.clean, and
isolating the VALID_PAGE() code will allow simplifying the overall logic.

Note, the VMCB probably doesn't need to be marked dirty when the VMSA is
invalid, as KVM will disallow running the vCPU in such a state.  But it
also doesn't hurt anything.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250227012541.3234589-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index a6971cd236bed..058d34622be35 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3921,6 +3921,12 @@ static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
 	/* Clear use of the VMSA */
 	svm->vmcb->control.vmsa_pa = INVALID_PAGE;
 
+	/*
+	 * When replacing the VMSA during SEV-SNP AP creation,
+	 * mark the VMCB dirty so that full state is always reloaded.
+	 */
+	vmcb_mark_all_dirty(svm->vmcb);
+
 	if (VALID_PAGE(svm->sev_es.snp_vmsa_gpa)) {
 		gfn_t gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
 		struct kvm_memory_slot *slot;
@@ -3966,12 +3972,6 @@ static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
 		kvm_release_pfn_clean(pfn);
 	}
 
-	/*
-	 * When replacing the VMSA during SEV-SNP AP creation,
-	 * mark the VMCB dirty so that full state is always reloaded.
-	 */
-	vmcb_mark_all_dirty(svm->vmcb);
-
 	return 0;
 }
 
-- 
2.53.0

[PATCH 6.12.y 2/6] KVM: SVM: Use guard(mutex) to simplify SNP vCPU state updates

[Sasha Levin]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 5279d6f7e43d9c5863411482943200bf5ab8a261 ]

Use guard(mutex) in sev_snp_init_protected_guest_state() and pull in its
lock-protected inner helper.  Without an unlock trampoline (and even with
one), there is no real need for an inner helper.  Eliminating the helper
also avoids having to fixup the open coded "lockdep" WARN_ON().

Opportunistically drop the error message if KVM can't obtain the pfn for
the new target VMSA.  The error message provides zero information that
can't be gleaned from the fact that the vCPU is stuck.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250227012541.3234589-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

[ This tree lacks upstream commit 1fbee5b01a0fd ("KVM: guest_memfd:
  Provide "struct page" as output from kvm_gmem_get_pfn()"), so its
  kvm_gmem_get_pfn() still uses the older pfn-only signature (no
  struct page **).  Adapted the refactored
  sev_snp_init_protected_guest_state() to keep calling
  kvm_gmem_get_pfn() without a page argument and to use
  kvm_release_pfn_clean(pfn) instead of kvm_release_page_clean(page). ]

Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 114 ++++++++++++++++++-----------------------
 1 file changed, 49 insertions(+), 65 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 058d34622be35..be6150ec1b2f2 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3908,11 +3908,25 @@ static int snp_begin_psc(struct vcpu_svm *svm)
 	BUG();
 }
 
-static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
+/*
+ * Invoked as part of svm_vcpu_reset() processing of an init event.
+ */
+void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
+	struct kvm_memory_slot *slot;
+	kvm_pfn_t pfn;
+	gfn_t gfn;
 
-	WARN_ON(!mutex_is_locked(&svm->sev_es.snp_vmsa_mutex));
+	if (!sev_snp_guest(vcpu->kvm))
+		return;
+
+	guard(mutex)(&svm->sev_es.snp_vmsa_mutex);
+
+	if (!svm->sev_es.snp_ap_waiting_for_reset)
+		return;
+
+	svm->sev_es.snp_ap_waiting_for_reset = false;
 
 	/* Mark the vCPU as offline and not runnable */
 	vcpu->arch.pv.pv_unhalted = false;
@@ -3927,78 +3941,48 @@ static int __sev_snp_update_protected_guest_state(struct kvm_vcpu *vcpu)
 	 */
 	vmcb_mark_all_dirty(svm->vmcb);
 
-	if (VALID_PAGE(svm->sev_es.snp_vmsa_gpa)) {
-		gfn_t gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
-		struct kvm_memory_slot *slot;
-		kvm_pfn_t pfn;
-
-		slot = gfn_to_memslot(vcpu->kvm, gfn);
-		if (!slot)
-			return -EINVAL;
-
-		/*
-		 * The new VMSA will be private memory guest memory, so
-		 * retrieve the PFN from the gmem backend.
-		 */
-		if (kvm_gmem_get_pfn(vcpu->kvm, slot, gfn, &pfn, NULL))
-			return -EINVAL;
-
-		/*
-		 * From this point forward, the VMSA will always be a
-		 * guest-mapped page rather than the initial one allocated
-		 * by KVM in svm->sev_es.vmsa. In theory, svm->sev_es.vmsa
-		 * could be free'd and cleaned up here, but that involves
-		 * cleanups like wbinvd_on_all_cpus() which would ideally
-		 * be handled during teardown rather than guest boot.
-		 * Deferring that also allows the existing logic for SEV-ES
-		 * VMSAs to be re-used with minimal SNP-specific changes.
-		 */
-		svm->sev_es.snp_has_guest_vmsa = true;
-
-		/* Use the new VMSA */
-		svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);
-
-		/* Mark the vCPU as runnable */
-		vcpu->arch.pv.pv_unhalted = false;
-		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
-
-		svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
-
-		/*
-		 * gmem pages aren't currently migratable, but if this ever
-		 * changes then care should be taken to ensure
-		 * svm->sev_es.vmsa is pinned through some other means.
-		 */
-		kvm_release_pfn_clean(pfn);
-	}
+	if (!VALID_PAGE(svm->sev_es.snp_vmsa_gpa))
+		return;
 
-	return 0;
-}
+	gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
 
-/*
- * Invoked as part of svm_vcpu_reset() processing of an init event.
- */
-void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
-{
-	struct vcpu_svm *svm = to_svm(vcpu);
-	int ret;
+	slot = gfn_to_memslot(vcpu->kvm, gfn);
+	if (!slot)
+		return;
 
-	if (!sev_snp_guest(vcpu->kvm))
+	/*
+	 * The new VMSA will be private memory guest memory, so retrieve the
+	 * PFN from the gmem backend.
+	 */
+	if (kvm_gmem_get_pfn(vcpu->kvm, slot, gfn, &pfn, NULL))
 		return;
 
-	mutex_lock(&svm->sev_es.snp_vmsa_mutex);
+	/*
+	 * From this point forward, the VMSA will always be a guest-mapped page
+	 * rather than the initial one allocated by KVM in svm->sev_es.vmsa. In
+	 * theory, svm->sev_es.vmsa could be free'd and cleaned up here, but
+	 * that involves cleanups like wbinvd_on_all_cpus() which would ideally
+	 * be handled during teardown rather than guest boot.  Deferring that
+	 * also allows the existing logic for SEV-ES VMSAs to be re-used with
+	 * minimal SNP-specific changes.
+	 */
+	svm->sev_es.snp_has_guest_vmsa = true;
 
-	if (!svm->sev_es.snp_ap_waiting_for_reset)
-		goto unlock;
+	/* Use the new VMSA */
+	svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);
 
-	svm->sev_es.snp_ap_waiting_for_reset = false;
+	/* Mark the vCPU as runnable */
+	vcpu->arch.pv.pv_unhalted = false;
+	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 
-	ret = __sev_snp_update_protected_guest_state(vcpu);
-	if (ret)
-		vcpu_unimpl(vcpu, "snp: AP state update on init failed\n");
+	svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
 
-unlock:
-	mutex_unlock(&svm->sev_es.snp_vmsa_mutex);
+	/*
+	 * gmem pages aren't currently migratable, but if this ever changes
+	 * then care should be taken to ensure svm->sev_es.vmsa is pinned
+	 * through some other means.
+	 */
+	kvm_release_pfn_clean(pfn);
 }
 
 static int sev_snp_ap_creation(struct vcpu_svm *svm)
-- 
2.53.0

[PATCH 6.12.y 3/6] KVM: SVM: Invalidate "next" SNP VMSA GPA even on failure

[Sasha Levin]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 4e96f010afb2815e33c9b15a695e0e0b4cb3cea6 ]

When processing an SNP AP Creation event, invalidate the "next" VMSA GPA
even if acquiring the page/pfn for the new VMSA fails.  In practice, the
next GPA will never be used regardless of whether or not its invalidated,
as the entire flow is guarded by snp_ap_waiting_for_reset, and said guard
and snp_vmsa_gpa are always written as a pair.  But that's really hard to
see in the code.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250227012541.3234589-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index be6150ec1b2f2..7a94a5f0ca805 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3945,6 +3945,7 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 		return;
 
 	gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
+	svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
 
 	slot = gfn_to_memslot(vcpu->kvm, gfn);
 	if (!slot)
@@ -3975,8 +3976,6 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 	vcpu->arch.pv.pv_unhalted = false;
 	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
 
-	svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
-
 	/*
 	 * gmem pages aren't currently migratable, but if this ever changes
 	 * then care should be taken to ensure svm->sev_es.vmsa is pinned
-- 
2.53.0

[PATCH 6.12.y 4/6] KVM: SEV: Disable SEV-SNP support on initialization failure

[Sasha Levin]

From: Ashish Kalra <ashish.kalra@amd.com>

[ Upstream commit 179a8427fcbffe36ccfed5e138d7c9b6180caff9 ]

During platform init, SNP initialization may fail for several reasons,
such as firmware command failures and incompatible versions. However,
the KVM capability may continue to advertise support for it.

The platform may have SNP enabled but if SNP_INIT fails then SNP is
not supported by KVM.

During KVM module initialization query the SNP platform status to obtain
the SNP initialization state and use it as an additional condition to
determine support for SEV-SNP.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Pratik R. Sampat <prsampat@amd.com>
Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Reviewed-by: Pavan Kumar Paluri <papaluri@amd.com>
Message-ID: <20250512221634.12045-1-Ashish.Kalra@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 44 +++++++++++++++++++++++++++++++++---------
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 7a94a5f0ca805..d4026cd634c0f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2984,6 +2984,33 @@ void __init sev_set_cpu_caps(void)
 	}
 }
 
+static bool is_sev_snp_initialized(void)
+{
+	struct sev_user_data_snp_status *status;
+	struct sev_data_snp_addr buf;
+	bool initialized = false;
+	int ret, error = 0;
+
+	status = snp_alloc_firmware_page(GFP_KERNEL | __GFP_ZERO);
+	if (!status)
+		return false;
+
+	buf.address = __psp_pa(status);
+	ret = sev_do_cmd(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &error);
+	if (ret) {
+		pr_err("SEV: SNP_PLATFORM_STATUS failed ret=%d, fw_error=%d (%#x)\n",
+		       ret, error, error);
+		goto out;
+	}
+
+	initialized = !!status->state;
+
+out:
+	snp_free_firmware_page(status);
+
+	return initialized;
+}
+
 void __init sev_hardware_setup(void)
 {
 	unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
@@ -3088,6 +3115,14 @@ void __init sev_hardware_setup(void)
 	sev_snp_supported = sev_snp_enabled && cc_platform_has(CC_ATTR_HOST_SEV_SNP);
 
 out:
+	if (sev_enabled) {
+		init_args.probe = true;
+		if (sev_platform_init(&init_args))
+			sev_supported = sev_es_supported = sev_snp_supported = false;
+		else if (sev_snp_supported)
+			sev_snp_supported = is_sev_snp_initialized();
+	}
+
 	if (boot_cpu_has(X86_FEATURE_SEV))
 		pr_info("SEV %s (ASIDs %u - %u)\n",
 			sev_supported ? min_sev_asid <= max_sev_asid ? "enabled" :
@@ -3114,15 +3149,6 @@ void __init sev_hardware_setup(void)
 	sev_supported_vmsa_features = 0;
 	if (sev_es_debug_swap_enabled)
 		sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP;
-
-	if (!sev_enabled)
-		return;
-
-	/*
-	 * Do both SNP and SEV initialization at KVM module load.
-	 */
-	init_args.probe = true;
-	sev_platform_init(&init_args);
 }
 
 void sev_hardware_unsetup(void)
-- 
2.53.0

[PATCH 6.12.y 5/6] KVM: SVM: Move SEV-ES VMSA allocation to a dedicated sev_vcpu_create() helper

[Sasha Levin]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 34bd82aab15b8b9e8e9d923267283c84aa8c2789 ]

Add a dedicated sev_vcpu_create() helper to allocate the VMSA page for
SEV-ES+ vCPUs, and to allow for consolidating a variety of related SEV+
code in the near future.

No functional change intended.

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/r/20250819234833.3080255-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 20 ++++++++++++++++++++
 arch/x86/kvm/svm/svm.c | 25 +++++++------------------
 arch/x86/kvm/svm/svm.h |  2 ++
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index d4026cd634c0f..ca07b2c05a4c6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4669,6 +4669,26 @@ void sev_init_vmcb(struct vcpu_svm *svm)
 		sev_es_init_vmcb(svm);
 }
 
+int sev_vcpu_create(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+	struct page *vmsa_page;
+
+	if (!sev_es_guest(vcpu->kvm))
+		return 0;
+
+	/*
+	 * SEV-ES guests require a separate (from the VMCB) VMSA page used to
+	 * contain the encrypted register state of the guest.
+	 */
+	vmsa_page = snp_safe_alloc_page();
+	if (!vmsa_page)
+		return -ENOMEM;
+
+	svm->sev_es.vmsa = page_address(vmsa_page);
+	return 0;
+}
+
 void sev_es_vcpu_reset(struct vcpu_svm *svm)
 {
 	struct kvm_vcpu *vcpu = &svm->vcpu;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 44819d9470dcf..c996f07b9c80a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1433,7 +1433,6 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm;
 	struct page *vmcb01_page;
-	struct page *vmsa_page = NULL;
 	int err;
 
 	BUILD_BUG_ON(offsetof(struct vcpu_svm, vcpu) != 0);
@@ -1444,24 +1443,18 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu)
 	if (!vmcb01_page)
 		goto out;
 
-	if (sev_es_guest(vcpu->kvm)) {
-		/*
-		 * SEV-ES guests require a separate VMSA page used to contain
-		 * the encrypted register state of the guest.
-		 */
-		vmsa_page = snp_safe_alloc_page();
-		if (!vmsa_page)
-			goto error_free_vmcb_page;
-	}
+	err = sev_vcpu_create(vcpu);
+	if (err)
+		goto error_free_vmcb_page;
 
 	err = avic_init_vcpu(svm);
 	if (err)
-		goto error_free_vmsa_page;
+		goto error_free_sev;
 
 	svm->msrpm = svm_vcpu_alloc_msrpm();
 	if (!svm->msrpm) {
 		err = -ENOMEM;
-		goto error_free_vmsa_page;
+		goto error_free_sev;
 	}
 
 	svm->x2avic_msrs_intercepted = true;
@@ -1471,16 +1464,12 @@ static int svm_vcpu_create(struct kvm_vcpu *vcpu)
 	svm->vmcb01.pa = __sme_set(page_to_pfn(vmcb01_page) << PAGE_SHIFT);
 	svm_switch_vmcb(svm, &svm->vmcb01);
 
-	if (vmsa_page)
-		svm->sev_es.vmsa = page_address(vmsa_page);
-
 	svm->guest_state_loaded = false;
 
 	return 0;
 
-error_free_vmsa_page:
-	if (vmsa_page)
-		__free_page(vmsa_page);
+error_free_sev:
+	sev_free_vcpu(vcpu);
 error_free_vmcb_page:
 	__free_page(vmcb01_page);
 out:
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c34cd7f1408fc..a595064d6a52f 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -757,6 +757,7 @@ static inline struct page *snp_safe_alloc_page(void)
 	return snp_safe_alloc_page_node(numa_node_id(), GFP_KERNEL_ACCOUNT);
 }
 
+int sev_vcpu_create(struct kvm_vcpu *vcpu);
 void sev_free_vcpu(struct kvm_vcpu *vcpu);
 void sev_vm_destroy(struct kvm *kvm);
 void __init sev_set_cpu_caps(void);
@@ -781,6 +782,7 @@ static inline struct page *snp_safe_alloc_page(void)
 	return snp_safe_alloc_page_node(numa_node_id(), GFP_KERNEL_ACCOUNT);
 }
 
+static inline int sev_vcpu_create(struct kvm_vcpu *vcpu) { return 0; }
 static inline void sev_free_vcpu(struct kvm_vcpu *vcpu) {}
 static inline void sev_vm_destroy(struct kvm *kvm) {}
 static inline void __init sev_set_cpu_caps(void) {}
-- 
2.53.0

[PATCH 6.12.y 6/6] KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests

[Sasha Levin]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 42a39ad5d592aec87a70527a4e694f6210694482 ]

Track the GPA of the guest-provided VMSA used after AP_CREATION events when
running SNP guests, instead of simply tracking whether or not the vCPU is
using a guest-provided VMSA.  KVM needs to know the GPA of the VMSA that's
actively being used so that it can react to MMU invalidation events, i.e.
so that KVM can drop the VMSA if its backing guest_memfd page is punched
out of existence.

Opportunistically rename snp_vmsa_gpa to clarify that it tracks the pending
VMSA GPA, whereas snp_guest_vmsa_gpa now tracks the in-use VMSA GPA.

Note!  Take care to track the GPA, not the GFN, as VALID_PAGE() won't
behave correctly if an invalid GFN is converted to a GPA for checking.

Note #2!  Keep snp_has_guest_vmsa so that switching to a guest-provided
VMSA is sticky, even if the guest-provided VMSA becomes invalid.

No functional change intended.

Cc: stable@vger.kernel.org # 6.12.x
Reviewed-by: Michael Roth <michael.roth@amd.com>
Link: https://patch.msgid.link/20260709204948.1988414-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
[ dropped the guest_tsc_protected line since Secure TSC support (a311fce2b6945) is not present in this tree ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 15 ++++++++++-----
 arch/x86/kvm/svm/svm.h |  3 ++-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index ca07b2c05a4c6..c8723aa2e0f40 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3960,6 +3960,7 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 
 	/* Clear use of the VMSA */
 	svm->vmcb->control.vmsa_pa = INVALID_PAGE;
+	svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE;
 
 	/*
 	 * When replacing the VMSA during SEV-SNP AP creation,
@@ -3967,11 +3968,11 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 	 */
 	vmcb_mark_all_dirty(svm->vmcb);
 
-	if (!VALID_PAGE(svm->sev_es.snp_vmsa_gpa))
+	if (!VALID_PAGE(svm->sev_es.snp_pending_vmsa_gpa))
 		return;
 
-	gfn = gpa_to_gfn(svm->sev_es.snp_vmsa_gpa);
-	svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+	gfn = gpa_to_gfn(svm->sev_es.snp_pending_vmsa_gpa);
+	svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
 
 	slot = gfn_to_memslot(vcpu->kvm, gfn);
 	if (!slot)
@@ -3996,6 +3997,7 @@ void sev_snp_init_protected_guest_state(struct kvm_vcpu *vcpu)
 	svm->sev_es.snp_has_guest_vmsa = true;
 
 	/* Use the new VMSA */
+	svm->sev_es.snp_guest_vmsa_gpa = gfn_to_gpa(gfn);
 	svm->vmcb->control.vmsa_pa = pfn_to_hpa(pfn);
 
 	/* Mark the vCPU as runnable */
@@ -4086,10 +4088,10 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 			goto out;
 		}
 
-		target_svm->sev_es.snp_vmsa_gpa = svm->vmcb->control.exit_info_2;
+		target_svm->sev_es.snp_pending_vmsa_gpa = svm->vmcb->control.exit_info_2;
 		break;
 	case SVM_VMGEXIT_AP_DESTROY:
-		target_svm->sev_es.snp_vmsa_gpa = INVALID_PAGE;
+		target_svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
 		break;
 	default:
 		vcpu_unimpl(vcpu, "vmgexit: invalid AP creation request [%#x] from guest\n",
@@ -4686,6 +4688,9 @@ int sev_vcpu_create(struct kvm_vcpu *vcpu)
 		return -ENOMEM;
 
 	svm->sev_es.vmsa = page_address(vmsa_page);
+	svm->sev_es.snp_pending_vmsa_gpa = INVALID_PAGE;
+	svm->sev_es.snp_guest_vmsa_gpa = INVALID_PAGE;
+
 	return 0;
 }
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index a595064d6a52f..26ed4ab3b257a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -238,7 +238,8 @@ struct vcpu_sev_es_state {
 	u64 ghcb_registered_gpa;
 
 	struct mutex snp_vmsa_mutex; /* Used to handle concurrent updates of VMSA. */
-	gpa_t snp_vmsa_gpa;
+	gpa_t snp_pending_vmsa_gpa;
+	gpa_t snp_guest_vmsa_gpa;
 	bool snp_ap_waiting_for_reset;
 	bool snp_has_guest_vmsa;
 };
-- 
2.53.0

Re: [PATCH 6.12.y 2/6] KVM: SVM: Use guard(mutex) to simplify SNP vCPU state updates

[Sean Christopherson]

On Mon, Aug 31, 2026, Sasha Levin wrote:
> From: Sean Christopherson <seanjc@google.com>
> 
> [ Upstream commit 5279d6f7e43d9c5863411482943200bf5ab8a261 ]
> 
> Use guard(mutex) in sev_snp_init_protected_guest_state() and pull in its
> lock-protected inner helper.  Without an unlock trampoline (and even with
> one), there is no real need for an inner helper.  Eliminating the helper
> also avoids having to fixup the open coded "lockdep" WARN_ON().
> 
> Opportunistically drop the error message if KVM can't obtain the pfn for
> the new target VMSA.  The error message provides zero information that
> can't be gleaned from the fact that the vCPU is stuck.
> 
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> Link: https://lore.kernel.org/r/20250227012541.3234589-10-seanjc@google.com
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> 
> [ This tree lacks upstream commit 1fbee5b01a0fd ("KVM: guest_memfd:
>   Provide "struct page" as output from kvm_gmem_get_pfn()"), so its
>   kvm_gmem_get_pfn() still uses the older pfn-only signature (no
>   struct page **).  Adapted the refactored
>   sev_snp_init_protected_guest_state() to keep calling
>   kvm_gmem_get_pfn() without a page argument and to use
>   kvm_release_pfn_clean(pfn) instead of kvm_release_page_clean(page). ]
> 
> Stable-dep-of: 42a39ad5d592 ("KVM: SEV: Track the GPA of the guest-controlled VMSA used for SNP guests")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---

Acked-by: Sean Christopherson <seanjc@google.com>