[PATCH 4.19 044/361] x86/kvm/nVMX: allow bare VMXON state migration

Greg Kroah-Hartman
2018-11-12T00:16:19Z

From: Vitaly Kuznetsov <vkuznets@redhat.com>

commit a1b0c1c64dfef0cff8555bb708bfc5d7c66c6ca4 upstream.

It is perfectly valid for a guest to do VMXON and not do VMPTRLD. This
state needs to be preserved on migration.

Cc: stable@vger.kernel.org
Fixes: 8fcc4b5923af5de58b80b53a069453b135693304
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/vmx.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -14010,13 +14010,6 @@ static int vmx_set_nested_state(struct k
if (!page_address_valid(vcpu, kvm_state->vmx.vmxon_pa))
return -EINVAL;

- if (kvm_state->size < sizeof(kvm_state) + sizeof(*vmcs12))
- return -EINVAL;
-
- if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
- !page_address_valid(vcpu, kvm_state->vmx.vmcs_pa))
- return -EINVAL;
-
if ((kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
(kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE))
return -EINVAL;
@@ -14046,6 +14039,14 @@ static int vmx_set_nested_state(struct k
if (ret)
return ret;

+ /* Empty 'VMXON' state is permitted */
+ if (kvm_state->size < sizeof(kvm_state) + sizeof(*vmcs12))
+ return 0;
+
+ if (kvm_state->vmx.vmcs_pa == kvm_state->vmx.vmxon_pa ||
+ !page_address_valid(vcpu, kvm_state->vmx.vmcs_pa))
+ return -EINVAL;
+
set_current_vmptr(vmx, kvm_state->vmx.vmcs_pa);

if (kvm_state->vmx.smm.flags & KVM_STATE_NESTED_SMM_VMXON) {