[PATCH 5.5 251/367] KVM: VMX: Add non-canonical check on writes to RTIT address MSRs

Greg Kroah-Hartman
2020-02-10T12:56:29Z

From: Sean Christopherson <sean.j.christopherson@intel.com>

commit fe6ed369fca98e99df55c932b85782a5687526b5 upstream.

Reject writes to RTIT address MSRs if the data being written is a
non-canonical address as the MSRs are subject to canonical checks, e.g.
KVM will trigger an unchecked #GP when loading the values to hardware
during pt_guest_enter().

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/vmx/vmx.c | 2 ++
1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2146,6 +2146,8 @@ static int vmx_set_msr(struct kvm_vcpu *
(index >= 2 * intel_pt_validate_cap(vmx->pt_desc.caps,
PT_CAP_num_address_ranges)))
return 1;
+ if (is_noncanonical_address(data, vcpu))
+ return 1;
if (index % 2)
vmx->pt_desc.guest.addr_b[index / 2] = data;
else