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 v2 12/29] KVM: nSVM: Drop svm->nested.initialized
Date: Thu, 8 Oct 2026 00:14:08 +0000 [thread overview]
Message-ID: <20261008001425.2458927-13-yosry@kernel.org> (raw)
In-Reply-To: <20261008001425.2458927-1-yosry@kernel.org>
Do NULL checks on svm->nested.vmcb02.ptr instead of using a dedicated
proxy 'initialized' field. Make sure svm->nested.vmcb02.ptr is
correctly set to NULL on initialization failures, as it is currently
left as a dangling pointer.
This makes it possible to directly do a NULL check on
svm->nested.vmcb02.ptr before using it, instead of checking a different
field, which is less error-prone.
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
---
arch/x86/kvm/svm/nested.c | 14 ++++++--------
arch/x86/kvm/svm/svm.h | 2 --
2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 5d63ae47ebb6c..bfb297b7d71ab 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1142,7 +1142,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
return ret;
}
- if (WARN_ON_ONCE(!svm->nested.initialized))
+ if (WARN_ON_ONCE(!svm->nested.vmcb02.ptr))
return -EINVAL;
vmcb12_gpa = kvm_rax_read(vcpu);
@@ -1489,21 +1489,21 @@ int svm_allocate_nested(struct vcpu_svm *svm)
{
struct page *vmcb02_page;
- if (svm->nested.initialized)
+ if (svm->nested.vmcb02.ptr)
return 0;
vmcb02_page = snp_safe_alloc_page();
if (!vmcb02_page)
return -ENOMEM;
- svm->nested.vmcb02.ptr = page_address(vmcb02_page);
- svm->nested.vmcb02.pa = __sme_set(page_to_pfn(vmcb02_page) << PAGE_SHIFT);
svm->nested.msrpm = svm_vcpu_alloc_msrpm();
if (!svm->nested.msrpm)
goto err_free_vmcb02;
svm->nested.vmcb02.cpu = -1;
- svm->nested.initialized = true;
+ svm->nested.vmcb02.ptr = page_address(vmcb02_page);
+ svm->nested.vmcb02.pa = __sme_set(page_to_pfn(vmcb02_page) << PAGE_SHIFT);
+
return 0;
err_free_vmcb02:
@@ -1513,7 +1513,7 @@ int svm_allocate_nested(struct vcpu_svm *svm)
void svm_free_nested(struct vcpu_svm *svm)
{
- if (!svm->nested.initialized)
+ if (!svm->nested.vmcb02.ptr)
return;
if (WARN_ON_ONCE(svm->vmcb != svm->vmcb01.ptr))
@@ -1533,8 +1533,6 @@ void svm_free_nested(struct vcpu_svm *svm)
* When the vmcb02 is freed, this optimization becomes invalid.
*/
svm->nested.last_vmcb12_gpa = INVALID_GPA;
-
- svm->nested.initialized = false;
}
void svm_leave_nested(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index d386f2a4f72d7..2e1b5481ddd92 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -234,8 +234,6 @@ struct svm_nested_state {
*/
struct vmcb_save_area_cached save;
- bool initialized;
-
/*
* Indicates whether MSR bitmap for L2 needs to be rebuilt due to
* changes in MSR bitmap for L1 or switching to a different L2. Note,
--
2.56.0.360.g66cac248cb-goog
next prev parent reply other threads:[~2026-10-08 0:14 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 0:13 [PATCH v2 00/29] KVM: nSVM: Optimize nSVM TLB flushes Yosry Ahmed
2026-10-08 0:13 ` [PATCH v2 01/29] KVM: nSVM: Flush the TLB after forcefully leaving nested Yosry Ahmed
2026-10-08 0:13 ` [PATCH v2 02/29] KVM: SVM: Document number of ASIDs CPUID setting Yosry Ahmed
2026-10-08 0:13 ` [PATCH v2 03/29] KVM: VMX: Generalize VPID allocation to be vendor-neutral Yosry Ahmed
2026-10-08 0:30 ` sashiko-bot
2026-10-08 0:14 ` [PATCH v2 04/29] KVM: x86/mmu: Support specifying reserved TLB tags Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 05/29] KVM: SVM: Add helpers to set/clear ASID flush in VMCB Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 06/29] KVM: SVM: Fallback to flush everything if FLUSHBYASID is not available Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 07/29] KVM: SEV: Do ASID initialization at VMCB initialization Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 08/29] KVM: SEV: Expose sev_get_asid() outside of sev.c Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 09/29] KVM: SEV: Explicitly initialize the per vCPU ASID on SEV VM migration Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 10/29] KVM: SVM: Use a static ASID per vCPU Yosry Ahmed
2026-10-08 0:30 ` sashiko-bot
2026-10-08 0:14 ` [PATCH v2 11/29] KVM: SVM: Only flush the fallback ASID when used by a different vCPU Yosry Ahmed
2026-10-08 0:33 ` sashiko-bot
2026-10-08 0:14 ` Yosry Ahmed [this message]
2026-10-08 0:14 ` [PATCH v2 13/29] KVM: nSVM: Add a placeholder ASID for L2 Yosry Ahmed
2026-10-08 0:42 ` sashiko-bot
2026-10-08 0:14 ` [PATCH v2 14/29] KVM: x86: hyper-v: Rename kvm_hv_vcpu_purge_flush_tlb() Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 15/29] KVM: x86: hyper-v: Allow purging all TLB flush FIFOs Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 16/29] KVM: nSVM: Flush both L1 and L2 ASIDs on KVM_REQ_TLB_FLUSH Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 17/29] KVM: nSVM: Always switch VMCB before leaving guest mode Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 18/29] KVM: nSVM: Split nested_svm_transition_tlb_flush() into entry/exit fns Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 19/29] KVM: nSVM: Service local TLB flushes before nested transitions Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 20/29] KVM: x86: Add KVM_REQ_MMU_SYNC_ALL_ROOTS Yosry Ahmed
2026-10-08 3:29 ` Lai Jiangshan
2026-10-08 0:14 ` [PATCH v2 21/29] KVM: nSVM: Handle nested TLB flush requests through TLB_CONTROL Yosry Ahmed
2026-10-08 0:36 ` sashiko-bot
2026-10-08 0:14 ` [PATCH v2 22/29] KVM: nSVM: Flush the TLB if L1 changes L2's ASID in vmcb12 Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 23/29] KVM: nSVM: Do not reset TLB_CONTROL in vmcb02 on nested VM-Enter Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 24/29] KVM: x86/mmu: Rename __kvm_mmu_invalidate_addr() to kvm_mmu_sync_addr() Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 25/29] KVM: x86/mmu: Refactor kvm_mmu_invlpg() to allow skipping the GVA flush Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 26/29] KVM: nSVM: Flush L2's ASID when emulating INVLPGA Yosry Ahmed
2026-10-08 0:45 ` sashiko-bot
2026-10-08 0:14 ` [PATCH v2 27/29] KVM: nSVM: Flush the ASID on nested transitions if shared by L1 and L2 Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 28/29] KVM: nSVM: Use different ASIDs for " Yosry Ahmed
2026-10-08 0:14 ` [PATCH v2 29/29] KVM: selftests: Add a test for nested TLB flushes Yosry Ahmed
2026-10-08 0:35 ` sashiko-bot
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