From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v2] kvm: nVMX: VMCLEAR an active shadow VMCS after last use Date: Wed, 2 Nov 2016 19:04:46 +0100 Message-ID: References: <1477668579-22555-1-git-send-email-jmattson@google.com> <3b4e2b95-530d-4a69-14c7-4f622478560b@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Bandan Das , David Matlack , Peter Feiner To: Jim Mattson Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42274 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756558AbcKBSEw (ORCPT ); Wed, 2 Nov 2016 14:04:52 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 02/11/2016 18:56, Jim Mattson wrote: > Sorry; I changed the title after reworking the patch. V1 was "[PATCH] > kvm: nVMX: Track active shadow VMCSs" (15 July 2016). Aha, now it makes sense. I'm queuing it for -rc4. Thanks, Paolo > On Wed, Nov 2, 2016 at 10:23 AM, Paolo Bonzini wrote: >> On 28/10/2016 17:29, Jim Mattson wrote: >>> After a successful VM-entry with the "VMCS shadowing" VM-execution >>> control set, the shadow VMCS referenced by the VMCS link pointer field >>> in the current VMCS becomes active on the logical processor. >>> >>> A VMCS that is made active on more than one logical processor may become >>> corrupted. Therefore, before an active VMCS can be migrated to another >>> logical processor, the first logical processor must execute a VMCLEAR >>> for the active VMCS. VMCLEAR both ensures that all VMCS data are written >>> to memory and makes the VMCS inactive. >>> >>> Signed-off-by: Jim Mattson >>> Reviewed-By: David Matlack >> >> The patch looks good but---sorry for the possibly stupid >> question---where was v1? >> >> Paolo >> >>> --- >>> arch/x86/kvm/vmx.c | 22 +++++++++++++++------- >>> 1 file changed, 15 insertions(+), 7 deletions(-) >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index cf0b7be..046b03f 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -187,6 +187,7 @@ struct vmcs { >>> */ >>> struct loaded_vmcs { >>> struct vmcs *vmcs; >>> + struct vmcs *shadow_vmcs; >>> int cpu; >>> int launched; >>> struct list_head loaded_vmcss_on_cpu_link; >>> @@ -411,7 +412,6 @@ struct nested_vmx { >>> * memory during VMXOFF, VMCLEAR, VMPTRLD. >>> */ >>> struct vmcs12 *cached_vmcs12; >>> - struct vmcs *current_shadow_vmcs; >>> /* >>> * Indicates if the shadow vmcs must be updated with the >>> * data hold by vmcs12 >>> @@ -1419,6 +1419,8 @@ static void vmcs_clear(struct vmcs *vmcs) >>> static inline void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs) >>> { >>> vmcs_clear(loaded_vmcs->vmcs); >>> + if (loaded_vmcs->shadow_vmcs && loaded_vmcs->launched) >>> + vmcs_clear(loaded_vmcs->shadow_vmcs); >>> loaded_vmcs->cpu = -1; >>> loaded_vmcs->launched = 0; >>> } >>> @@ -3562,6 +3564,7 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) >>> loaded_vmcs_clear(loaded_vmcs); >>> free_vmcs(loaded_vmcs->vmcs); >>> loaded_vmcs->vmcs = NULL; >>> + WARN_ON(loaded_vmcs->shadow_vmcs != NULL); >>> } >>> >>> static void free_kvm_area(void) >>> @@ -6696,6 +6699,7 @@ static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx) >>> if (!item) >>> return NULL; >>> item->vmcs02.vmcs = alloc_vmcs(); >>> + item->vmcs02.shadow_vmcs = NULL; >>> if (!item->vmcs02.vmcs) { >>> kfree(item); >>> return NULL; >>> @@ -7072,7 +7076,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu) >>> shadow_vmcs->revision_id |= (1u << 31); >>> /* init shadow vmcs */ >>> vmcs_clear(shadow_vmcs); >>> - vmx->nested.current_shadow_vmcs = shadow_vmcs; >>> + vmx->vmcs01.shadow_vmcs = shadow_vmcs; >>> } >>> >>> INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool)); >>> @@ -7174,8 +7178,11 @@ static void free_nested(struct vcpu_vmx *vmx) >>> free_page((unsigned long)vmx->nested.msr_bitmap); >>> vmx->nested.msr_bitmap = NULL; >>> } >>> - if (enable_shadow_vmcs) >>> - free_vmcs(vmx->nested.current_shadow_vmcs); >>> + if (enable_shadow_vmcs) { >>> + vmcs_clear(vmx->vmcs01.shadow_vmcs); >>> + free_vmcs(vmx->vmcs01.shadow_vmcs); >>> + vmx->vmcs01.shadow_vmcs = NULL; >>> + } >>> kfree(vmx->nested.cached_vmcs12); >>> /* Unpin physical memory we referred to in current vmcs02 */ >>> if (vmx->nested.apic_access_page) { >>> @@ -7352,7 +7359,7 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) >>> int i; >>> unsigned long field; >>> u64 field_value; >>> - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; >>> + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; >>> const unsigned long *fields = shadow_read_write_fields; >>> const int num_fields = max_shadow_read_write_fields; >>> >>> @@ -7401,7 +7408,7 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) >>> int i, q; >>> unsigned long field; >>> u64 field_value = 0; >>> - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; >>> + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; >>> >>> vmcs_load(shadow_vmcs); >>> >>> @@ -7591,7 +7598,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu) >>> vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, >>> SECONDARY_EXEC_SHADOW_VMCS); >>> vmcs_write64(VMCS_LINK_POINTER, >>> - __pa(vmx->nested.current_shadow_vmcs)); >>> + __pa(vmx->vmcs01.shadow_vmcs)); >>> vmx->nested.sync_shadow_vmcs = true; >>> } >>> } >>> @@ -9156,6 +9163,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) >>> >>> vmx->loaded_vmcs = &vmx->vmcs01; >>> vmx->loaded_vmcs->vmcs = alloc_vmcs(); >>> + vmx->loaded_vmcs->shadow_vmcs = NULL; >>> if (!vmx->loaded_vmcs->vmcs) >>> goto free_msrs; >>> if (!vmm_exclusive) >>>