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 <jmattson@google.com>
Reviewed-By: David Matlack <dmatlack@google.com>
Message-Id: <1477668579-22555-1-git-send-email-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 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 @@
* 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 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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)