From: Yosry Ahmed <yosry@kernel.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Yosry Ahmed <yosry@kernel.org>
Subject: [PATCH v3 17/27] KVM: nSVM: Always switch VMCB before leaving guest mode
Date: Mon, 12 Oct 2026 23:36:28 +0000 [thread overview]
Message-ID: <20261012233638.2546339-18-yosry@kernel.org> (raw)
In-Reply-To: <20261012233638.2546339-1-yosry@kernel.org>
Move svm_switch_vmcb() calls ahead of leave_guest_mode(), as nothing
between the calls depends on svm->vmcb being set to vmcb01. This makes
the nested VM-Exit path consistent with the nested VM-Enter path, and
having the calls to svm_switch_vmcb() and leave_guest_mode() close makes
it easier to reason about incoming changes that depend on both VMCB and
guest_mode context.
No functional change intended.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
---
arch/x86/kvm/svm/nested.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 75ada771026b2..27f78228a42d5 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1329,7 +1329,7 @@ void nested_svm_vmexit(struct vcpu_svm *svm)
if (nested_svm_vmexit_update_vmcb12(vcpu))
kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
- /* Exit Guest-Mode */
+ svm_switch_vmcb(svm, &svm->vmcb01);
leave_guest_mode(vcpu);
svm_pmu_handle_nested_transition(svm);
@@ -1356,8 +1356,6 @@ void nested_svm_vmexit(struct vcpu_svm *svm)
if (guest_cpu_cap_has(vcpu, X86_FEATURE_ERAPS))
vmcb01->control.erap_ctl |= ERAP_CONTROL_CLEAR_RAP;
- svm_switch_vmcb(svm, &svm->vmcb01);
-
/*
* Rules for synchronizing int_ctl bits from vmcb02 to vmcb01:
*
@@ -1543,6 +1541,7 @@ void svm_leave_nested(struct kvm_vcpu *vcpu)
vcpu->arch.nested_run_pending = 0;
svm->nested.vmcb12_gpa = INVALID_GPA;
+ svm_switch_vmcb(svm, &svm->vmcb01);
leave_guest_mode(vcpu);
/*
@@ -1554,8 +1553,6 @@ void svm_leave_nested(struct kvm_vcpu *vcpu)
*/
__svm_pmu_handle_nested_transition(svm, true);
- svm_switch_vmcb(svm, &svm->vmcb01);
-
nested_svm_transition_tlb_flush(vcpu);
nested_svm_uninit_mmu_context(vcpu);
--
2.56.0.385.gd3acb90ef8-goog
next prev parent reply other threads:[~2026-10-12 23:36 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-12 23:36 [PATCH v3 00/27] KVM: nSVM: Optimize nSVM TLB flushes Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 01/27] KVM: nSVM: Flush the TLB after forcefully leaving nested Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 02/27] KVM: SVM: Document number of ASIDs CPUID setting Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 03/27] KVM: VMX: Generalize VPID allocation to be vendor-neutral Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 04/27] KVM: x86/mmu: Support specifying reserved TLB tags Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 05/27] KVM: SVM: Add helpers to set/clear ASID flush in VMCB Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 06/27] KVM: SVM: Fallback to flush everything if FLUSHBYASID is not available Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 07/27] KVM: SEV: Do ASID initialization at VMCB initialization Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 08/27] KVM: SEV: Expose sev_get_asid() outside of sev.c Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 09/27] KVM: SEV: Explicitly initialize the per vCPU ASID on SEV VM migration Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 10/27] KVM: SVM: Use a static ASID per vCPU Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 11/27] KVM: SVM: Only flush the fallback ASID when used by a different vCPU Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 12/27] KVM: nSVM: Drop svm->nested.initialized Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 13/27] KVM: nSVM: Add a placeholder ASID for L2 Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 14/27] KVM: x86: hyper-v: Rename kvm_hv_vcpu_purge_flush_tlb() Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 15/27] KVM: x86: hyper-v: Allow purging all TLB flush FIFOs Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 16/27] KVM: nSVM: Flush both L1 and L2 ASIDs on KVM_REQ_TLB_FLUSH Yosry Ahmed
2026-10-12 23:36 ` Yosry Ahmed [this message]
2026-10-12 23:36 ` [PATCH v3 18/27] KVM: nSVM: Split nested_svm_transition_tlb_flush() into entry/exit fns Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 19/27] KVM: nSVM: Service local TLB flushes before nested transitions Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 20/27] KVM: x86: Add KVM_REQ_MMU_SYNC_ALL_ROOTS Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 21/27] KVM: nSVM: Handle nested TLB flush requests through TLB_CONTROL Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 22/27] KVM: nSVM: Flush the TLB if L1 changes L2's ASID in vmcb12 Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 23/27] KVM: nSVM: Do not reset TLB_CONTROL in vmcb02 on nested VM-Enter Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 24/27] KVM: nSVM: Flush L2's ASID when emulating INVLPGA Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 25/27] KVM: nSVM: Flush the ASID on nested transitions if shared by L1 and L2 Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 26/27] KVM: nSVM: Use different ASIDs for " Yosry Ahmed
2026-10-12 23:36 ` [PATCH v3 27/27] KVM: selftests: Add a test for nested TLB flushes Yosry Ahmed
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