From 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Fri, 28 Oct 2016 08:29:39 -0700 Subject: [PATCH] kvm: nVMX: VMCLEAR an active shadow VMCS after last use 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 Message-Id: <1477668579-22555-1-git-send-email-jmattson@google.com> Signed-off-by: Paolo Bonzini --- 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 754c3a7..5382b82 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 @@ -1418,6 +1418,8 @@ 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; } @@ -3533,6 +3535,7 @@ 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) @@ -6667,6 +6670,7 @@ 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; @@ -7043,7 +7047,7 @@ 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)); @@ -7145,8 +7149,11 @@ 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) { @@ -7323,7 +7330,7 @@ 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; @@ -7372,7 +7379,7 @@ 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); @@ -7562,7 +7569,7 @@ 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; } } @@ -9127,6 +9134,7 @@ 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) -- 2.7.4