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KVM: nVMX: mask unrestricted_guest if disabled on L0 

If EPT was enabled, unrestricted_guest was allowed in L1 regardless of
L0.  L1 triple faulted when running L2 guest that required emulation.

Another side effect was 'WARN_ON_ONCE(vmx->nested.nested_run_pending)'
in L0's dmesg:
  WARNING: CPU: 0 PID: 0 at arch/x86/kvm/vmx.c:9190 nested_vmx_vmexit+0x96e/0xb00 [kvm_intel] ()

Prevent this scenario by masking SECONDARY_EXEC_UNRESTRICTED_GUEST when
the host doesn't have it enabled.

Fixes: 78051e3b7e ("KVM: nVMX: Disable unrestricted mode if ept=0")
Cc: stable@vger.kernel.org
Tested-By: Kashyap Chamarthy <kchamart@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Radim Krčmář 2015-03-17 14:02:32 +01:00 committed by Marcelo Tosatti
parent c58616580e
commit 0790ec172d
1 changed files with 5 additions and 2 deletions
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7
arch/x86/kvm/vmx.c
View File

@ -2479,8 +2479,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
if (enable_ept) {
/* nested EPT: emulate EPT also to L1 */
vmx->nested.nested_vmx_secondary_ctls_high |=
SECONDARY_EXEC_ENABLE_EPT |
SECONDARY_EXEC_UNRESTRICTED_GUEST;
SECONDARY_EXEC_ENABLE_EPT;
vmx->nested.nested_vmx_ept_caps = VMX_EPT_PAGE_WALK_4_BIT |
VMX_EPTP_WB_BIT | VMX_EPT_2MB_PAGE_BIT |
VMX_EPT_INVEPT_BIT;
@ -2494,6 +2493,10 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
} else
vmx->nested.nested_vmx_ept_caps = 0;
if (enable_unrestricted_guest)
vmx->nested.nested_vmx_secondary_ctls_high |=
SECONDARY_EXEC_UNRESTRICTED_GUEST;
/* miscellaneous data */
rdmsr(MSR_IA32_VMX_MISC,
vmx->nested.nested_vmx_misc_low,