Kernel KVM virtualization development
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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 v1 08/28] KVM: SEV: Do ASID initialization at VMCB initialization
Date: Tue, 28 Jul 2026 00:35:37 +0000	[thread overview]
Message-ID: <20260728003557.1136583-9-yosry@kernel.org> (raw)
In-Reply-To: <20260728003557.1136583-1-yosry@kernel.org>

The per-vCPU ASID does not change for SEV guests, so move the per-vCPU
(and per-VMCB) ASID initialization to sev_init_vmcb() to do it once,
instead of checking before every VMRUN.

No functional change intended.

Signed-off-by: Yosry Ahmed <yosry@kernel.org>
---
 arch/x86/kvm/svm/sev.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0e5046a12a970..8717da0e9fe8a 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3580,14 +3580,6 @@ int pre_sev_run(struct vcpu_svm *svm, int cpu)
 	if (!cpumask_test_cpu(cpu, to_kvm_sev_info(kvm)->have_run_cpus))
 		cpumask_set_cpu(cpu, to_kvm_sev_info(kvm)->have_run_cpus);
 
-	/* Assign the asid allocated with this SEV guest */
-	svm->asid = asid;
-
-	if (unlikely(svm->asid != svm->vmcb->control.asid)) {
-		svm->vmcb->control.asid = asid;
-		vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
-	}
-
 	/*
 	 * Flush guest TLB:
 	 *
@@ -4829,6 +4821,10 @@ void sev_init_vmcb(struct vcpu_svm *svm, bool init_event)
 	svm->vmcb->control.misc_ctl |= SVM_MISC_ENABLE_SEV;
 	clr_exception_intercept(svm, UD_VECTOR);
 
+	svm->asid = sev_get_asid(vcpu->kvm);
+	svm->vmcb->control.asid = svm->asid;
+	vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
+
 	/*
 	 * Don't intercept #GP for SEV guests, e.g. for the VMware backdoor, as
 	 * KVM can't decrypt guest memory to decode the faulting instruction.
-- 
2.55.0.229.g6434b31f56-goog


  parent reply	other threads:[~2026-07-28  0:36 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-28  0:35 [PATCH v1 00/28] KVM: nSVM: Optimize nSVM TLB flushes Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 01/28] KVM: nSVM: Flush the TLB after forcefully leaving nested Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 02/28] KVM: SVM: Document number of ASIDs CPUID setting Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 03/28] KVM: VMX: Generalize VPID allocation to be vendor-neutral Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 04/28] KVM: x86/mmu: Support specifying reserved TLB tags Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 05/28] KVM: SVM: Add helpers to set/clear ASID flush in VMCB Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 06/28] KVM: SVM: Fallback to flush everything if FLUSHBYASID is not available Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 07/28] KVM: SVM: Duplicate pre-run ASID check for SEV and non-SEV guests Yosry Ahmed
2026-07-28  0:35 ` Yosry Ahmed [this message]
2026-07-28  0:35 ` [PATCH v1 09/28] KVM: SEV: Expose sev_get_asid() outside of sev.c Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 10/28] KVM: SVM: Use a static ASID per vCPU Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 11/28] KVM: SVM: Only flush the fallback ASID when used by a different vCPU Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 12/28] KVM: nSVM: Add a placeholder ASID for L2 Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 13/28] KVM: x86: hyper-v: Rename kvm_hv_vcpu_purge_flush_tlb() Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 14/28] KVM: x86: hyper-v: Allow puring all TLB flush FIFOs Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 15/28] KVM: nSVM: Drop svm->nested.initialized Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 16/28] KVM: nSVM: Flush both L1 and L2 ASIDs on KVM_REQ_TLB_FLUSH Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 17/28] KVM: nSVM: Always switch VMCB before leaving guest mode Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 18/28] KVM: nSVM: Split nested_svm_transition_tlb_flush() into entry/exit fns Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 19/28] KVM: nSVM: Service local TLB flushes before nested transitions Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 20/28] KVM: nSVM: Handle nested TLB flush requests through TLB_CONTROL Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 21/28] KVM: nSVM: Flush the TLB if L1 changes L2's ASID in vmcb12 Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 22/28] KVM: nSVM: Do not reset TLB_CONTROL in vmcb02 on nested VM-Enter Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 23/28] KVM: x86/mmu: Rename __kvm_mmu_invalidate_addr() to kvm_mmu_sync_addr() Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 24/28] KVM: x86/mmu: Refactor kvm_mmu_invlpg() to allow skipping the GVA flush Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 25/28] KVM: nSVM: Flush L2's ASID when emulating INVLPGA Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 26/28] KVM: nSVM: Flush the ASID on nested transitions if shared by L1 and L2 Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 27/28] KVM: nSVM: Use different ASIDs for " Yosry Ahmed
2026-07-28  0:35 ` [PATCH v1 28/28] KVM: selftests: Add a test for nested TLB flushes Yosry Ahmed
2026-07-28  1:05 ` [PATCH v1 00/28] KVM: nSVM: Optimize nSVM " Yosry Ahmed
2026-07-28  1:18   ` Sean Christopherson

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