kvm: x86: vmx: fix vpid leak (63aff655) · Commits · 戴 / test

VPID for the nested vcpu is allocated at vmx_create_vcpu whenever nested vmx is turned on with the module parameter. However, it's only freed if the L1 guest has executed VMXON which is not a given. As a result, on a system with nested==on every creation+deletion of an L1 vcpu without running an L2 guest results in leaking one vpid. Since the total number of vpids is limited to 64k, they can eventually get exhausted, preventing L2 from starting. Delay allocation of the L2 vpid until VMXON emulation, thus matching its freeing. Fixes: Cc: stable@vger.kernel.org Signed-off-by:

Roman Kagan <rkagan@virtuozzo.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -7893,6 +7893,8 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
		HRTIMER_MODE_REL_PINNED);
		vmx->nested.preemption_timer.function = vmx_preemption_timer_fn;

		vmx->nested.vpid02 = allocate_vpid();

		vmx->nested.vmxon = true;
		return 0;

		@@ -10369,11 +10371,9 @@ static struct kvm_vcpu vmx_create_vcpu(struct kvm kvm, unsigned int id)
		goto free_vmcs;
		}

		if (nested) {
		if (nested)
		nested_vmx_setup_ctls_msrs(&vmx->nested.msrs,
		kvm_vcpu_apicv_active(&vmx->vcpu));
		vmx->nested.vpid02 = allocate_vpid();
		}

		vmx->nested.posted_intr_nv = -1;
		vmx->nested.current_vmptr = -1ull;
		@@ -10390,7 +10390,6 @@ static struct kvm_vcpu vmx_create_vcpu(struct kvm kvm, unsigned int id)
		return &vmx->vcpu;

		free_vmcs:
		free_vpid(vmx->nested.vpid02);
		free_loaded_vmcs(vmx->loaded_vmcs);
		free_msrs:
		kfree(vmx->guest_msrs);

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