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From: Nikunj A Dadhania <nikunj@amd.com>
To: <kvm@vger.kernel.org>, <seanjc@google.com>, <pbonzini@redhat.com>
Cc: <thomas.lendacky@amd.com>, <bp@alien8.de>,
	<joao.m.martins@oracle.com>, <nikunj@amd.com>,
	<kai.huang@intel.com>, Pankaj Gupta <pankaj.gupta@amd.com>
Subject: [PATCH v6 3/7] KVM: VMX: Use cpu_dirty_log_size instead of enable_pml for PML checks
Date: Tue, 7 Apr 2026 06:32:41 +0000	[thread overview]
Message-ID: <20260407063245.2755579-4-nikunj@amd.com> (raw)
In-Reply-To: <20260407063245.2755579-1-nikunj@amd.com>

Replace the enable_pml check with cpu_dirty_log_size in VMX PML code
to determine whether PML is enabled on a per-VM basis. The enable_pml
module parameter is a global setting that doesn't reflect per-VM
capabilities, whereas cpu_dirty_log_size accurately indicates whether
a specific VM has PML enabled.

For example, TDX VMs don't yet support PML. Using cpu_dirty_log_size
ensures the check correctly reflects this, while enable_pml would
incorrectly indicate PML is available.

This also improves consistency with kvm_mmu_update_cpu_dirty_logging(),
which already uses cpu_dirty_log_size to determine PML enablement.

Suggested-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
 arch/x86/kvm/vmx/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 909085a5dfb3..a5a8bb5a7020 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -8439,7 +8439,7 @@ void vmx_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
-	if (WARN_ON_ONCE(!enable_pml))
+	if (WARN_ON_ONCE(!vcpu->kvm->arch.cpu_dirty_log_size))
 		return;
 
 	guard(vmx_vmcs01)(vcpu);
-- 
2.48.1


  parent reply	other threads:[~2026-04-07  6:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-07  6:32 [PATCH v6 0/7] KVM: SVM: Add Page Modification Logging (PML) support Nikunj A Dadhania
2026-04-07  6:32 ` [PATCH v6 1/7] KVM: x86: Carve out PML flush routine Nikunj A Dadhania
2026-04-07  6:32 ` [PATCH v6 2/7] KVM: x86: Move PML page to common vcpu arch structure Nikunj A Dadhania
2026-04-07  6:32 ` Nikunj A Dadhania [this message]
2026-04-07  6:32 ` [PATCH v6 4/7] x86/cpufeatures: Add Page modification logging Nikunj A Dadhania
2026-04-07  6:32 ` [PATCH v6 5/7] KVM: SVM: Use BIT_ULL for 64-bit nested_ctl bit definitions Nikunj A Dadhania
2026-04-07  6:32 ` [PATCH v6 6/7] KVM: nSVM: Add helpers to temporarily switch to vmcb01 Nikunj A Dadhania
2026-04-07  6:32 ` [PATCH v6 7/7] KVM: SVM: Add Page modification logging support Nikunj A Dadhania

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