KVM: VMX: Fix commit which broke PML (a3eaa864) · Commits · 戴 / test

I found PML was broken since below commit: commit Author: Xiao Guangrong <guangrong.xiao@linux.intel.com> Date: Wed Sep 9 14:05:55 2015 +0800 KVM: VMX: unify SECONDARY_VM_EXEC_CONTROL update Unify the update in vmx_cpuid_update() Signed-off-by:

Xiao Guangrong <guangrong.xiao@linux.intel.com> [Rewrite to use vmcs_set_secondary_exec_control. - Paolo] Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com> The reason is in above commit vmx_cpuid_update calls vmx_secondary_exec_control, in which currently SECONDARY_EXEC_ENABLE_PML bit is cleared unconditionally (as PML is enabled in creating vcpu). Therefore if vcpu_cpuid_update is called after vcpu is created, PML will be disabled unexpectedly while log-dirty code still thinks PML is used. Fix this by clearing SECONDARY_EXEC_ENABLE_PML in vmx_secondary_exec_control only when PML is not supported or not enabled (!enable_pml). This is more reasonable as PML is currently either always enabled or disabled. With this explicit updating SECONDARY_EXEC_ENABLE_PML in vmx_enable{disable}_pml is not needed so also rename vmx_enable{disable}_pml to vmx_create{destroy}_pml_buffer. Fixes: Signed-off-by:

Kai Huang <kai.huang@linux.intel.com> [While at it, change a wrong ASSERT to an "if". The condition can happen if creating the VCPU fails with ENOMEM. - Paolo] Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

+11 −13

Original line number	Diff line number	Diff line
		@@ -4718,7 +4718,8 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx)
		a current VMCS12
		*/
		exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS;
		/* PML is enabled/disabled in creating/destorying vcpu */

		if (!enable_pml)
		exec_control &= ~SECONDARY_EXEC_ENABLE_PML;

		/* Currently, we allow L1 guest to directly run pcommit instruction. */
		@@ -7804,7 +7805,7 @@ static void vmx_get_exit_info(struct kvm_vcpu vcpu, u64 info1, u64 *info2)
		*info2 = vmcs_read32(VM_EXIT_INTR_INFO);
		}

		static int vmx_enable_pml(struct vcpu_vmx *vmx)
		static int vmx_create_pml_buffer(struct vcpu_vmx *vmx)
		{
		struct page *pml_pg;

		@@ -7817,18 +7818,15 @@ static int vmx_enable_pml(struct vcpu_vmx *vmx)
		vmcs_write64(PML_ADDRESS, page_to_phys(vmx->pml_pg));
		vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1);

		vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML);

		return 0;
		}

		static void vmx_disable_pml(struct vcpu_vmx *vmx)
		static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx)
		{
		ASSERT(vmx->pml_pg);
		if (vmx->pml_pg) {
		__free_page(vmx->pml_pg);
		vmx->pml_pg = NULL;

		vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML);
		}
		}

		static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu)
		@@ -8706,7 +8704,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
		struct vcpu_vmx *vmx = to_vmx(vcpu);

		if (enable_pml)
		vmx_disable_pml(vmx);
		vmx_destroy_pml_buffer(vmx);
		free_vpid(vmx->vpid);
		leave_guest_mode(vcpu);
		vmx_load_vmcs01(vcpu);
		@@ -8790,7 +8788,7 @@ static struct kvm_vcpu vmx_create_vcpu(struct kvm kvm, unsigned int id)
		* for the guest, etc.
		*/
		if (enable_pml) {
		err = vmx_enable_pml(vmx);
		err = vmx_create_pml_buffer(vmx);
		if (err)
		goto free_vmcs;
		}

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