[PATCH v6 1/7] Check "load IA32_PAT" VM-exit control on vmentry

Sean Christopherson
2019-04-11T19:18:20Z

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

According to section "Checks on Host Control Registers and MSRs" in Intel
SDM vol 3C, the following check is performed on vmentry:

If the "load IA32_PAT" VM-exit 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 153e539c29c9..5133e0cf6eb9 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2590,6 +2590,10 @@ static int nested_check_host_control_regs(struct kvm_vcpu *vcpu,
is_noncanonical_address(vmcs12->host_ia32_sysenter_eip, vcpu))
return -EINVAL;

+ if ((vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_PAT) &&
+ !kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, vmcs12->host_ia32_pat))
+ return -EINVAL;
+
/*
* If the load IA32_EFER VM-exit control is 1, bits reserved in the
* IA32_EFER MSR must be 0 in the field for that register. In addition,
--
2.21.0