[PATCH v6 2/7] Check "load IA32_PAT" VM-entry control on vmentry

Sean Christopherson
2019-04-11T19:18:19Z

From: Krish Sadhukhan <krish.sadhukhan@oracle.com>

According to section "Checking and Loading Guest State" in Intel SDM vol
3C, the following check is performed on vmentry:

If the "load IA32_PAT" VM-entry control is 1, the value of the field
for the IA32_PAT MSR must be one that could be written by WRMSR
without fault at CPL 0. Specifically, each of the 8 bytes in the
field must have one of the values 0 (UC), 1 (WC), 4 (WT), 5 (WP),
6 (WB), or 7 (UC-).

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/nested.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 5133e0cf6eb9..f487aae3233e 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2680,6 +2680,10 @@ static int nested_vmx_check_vmentry_postreqs(struct kvm_vcpu *vcpu,
!nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4))
return 1;

+ if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) &&
+ !kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, vmcs12->guest_ia32_pat))
+ return 1;
+
if (nested_vmx_check_vmcs_link_ptr(vcpu, vmcs12)) {
*exit_qual = ENTRY_FAIL_VMCS_LINK_PTR;
return 1;
--
2.21.0