[PATCH 2/2] KVM: nVMX: Validate the IA32_BNDCFGS on nested VM-entry

From: Wanpeng Li
Date: Fri Oct 27 2017 - 02:51:15 EST


From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>

According to the SDM, if the "load IA32_BNDCFGS" VM-entry controls is 1, the
following checks are performed on the field for the IA32_BNDCFGS MSR:
- Bits reserved in the IA32_BNDCFGS MSR must be 0.
- The linear address in bits 63:12 must be canonical.

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e6c8ffa..f29f57d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10805,6 +10805,13 @@ static int check_vmentry_postreqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
return 1;
}

+ if (kvm_mpx_supported() &&
+ (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)) {
+ if (is_noncanonical_address(vmcs12->guest_bndcfgs & PAGE_MASK, vcpu) ||
+ (vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD))
+ return 1;
+ }
+
return 0;
}

--
2.7.4