[PATCH AUTOSEL for 4.4 12/32] kvm: nVMX: VMCLEAR should not cause the vCPU to shut down

From: alexander . levin
Date: Wed Nov 29 2017 - 12:28:28 EST


From: Jim Mattson <jmattson@xxxxxxxxxx>

[ Upstream commit 587d7e72aedca91cee80c0a56811649c3efab765 ]

VMCLEAR should silently ignore a failure to clear the launch state of
the VMCS referenced by the operand.

Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
[Changed "kvm_write_guest(vcpu->kvm" to "kvm_vcpu_write_guest(vcpu".]
Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>

Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 22 ++++------------------
1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9114588e3e61..aa8776848183 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6927,9 +6927,8 @@ static int handle_vmoff(struct kvm_vcpu *vcpu)
static int handle_vmclear(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
+ u32 zero = 0;
gpa_t vmptr;
- struct vmcs12 *vmcs12;
- struct page *page;

if (!nested_vmx_check_permission(vcpu))
return 1;
@@ -6940,22 +6939,9 @@ static int handle_vmclear(struct kvm_vcpu *vcpu)
if (vmptr == vmx->nested.current_vmptr)
nested_release_vmcs12(vmx);

- page = nested_get_page(vcpu, vmptr);
- if (page == NULL) {
- /*
- * For accurate processor emulation, VMCLEAR beyond available
- * physical memory should do nothing at all. However, it is
- * possible that a nested vmx bug, not a guest hypervisor bug,
- * resulted in this case, so let's shut down before doing any
- * more damage:
- */
- kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
- return 1;
- }
- vmcs12 = kmap(page);
- vmcs12->launch_state = 0;
- kunmap(page);
- nested_release_page(page);
+ kvm_vcpu_write_guest(vcpu,
+ vmptr + offsetof(struct vmcs12, launch_state),
+ &zero, sizeof(zero));

nested_free_vmcs02(vmx, vmptr);

--
2.11.0