KVM: nVMX: vmcs12 revision_id is always VMCS12_REVISION even when copied from eVMCS
vmcs12 represents the per-CPU cache of L1 active vmcs12.
This cache can be loaded by one of the following:
1) Guest making a vmcs12 active by exeucting VMPTRLD
2) Guest specifying eVMCS in VP assist page and executing
VMLAUNCH/VMRESUME.
Either way, vmcs12 should have revision_id of VMCS12_REVISION.
Which is not equal to eVMCS revision_id which specifies used
VersionNumber of eVMCS struct (e.g. KVM_EVMCS_VERSION).
Specifically, this causes an issue in restoring a nested VM state
because vmx_set_nested_state() verifies that vmcs12->revision_id
is equal to VMCS12_REVISION which was not true in case vmcs12
was populated from an eVMCS by vmx_get_nested_state() which calls
copy_enlightened_to_vmcs12().
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0ffd8b2..02edd99 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8673,8 +8673,6 @@ static int copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx)
struct vmcs12 *vmcs12 = vmx->nested.cached_vmcs12;
struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
- vmcs12->hdr.revision_id = evmcs->revision_id;
-
/* HV_VMX_ENLIGHTENED_CLEAN_FIELD_NONE */
vmcs12->tpr_threshold = evmcs->tpr_threshold;
vmcs12->guest_rip = evmcs->guest_rip;
@@ -9422,9 +9420,11 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
* present in struct hv_enlightened_vmcs, ...). Make sure there
* are no leftovers.
*/
- if (from_launch)
- memset(vmx->nested.cached_vmcs12, 0,
- sizeof(*vmx->nested.cached_vmcs12));
+ if (from_launch) {
+ struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+ memset(vmcs12, 0, sizeof(*vmcs12));
+ vmcs12->hdr.revision_id = VMCS12_REVISION;
+ }
}
return 1;