[PATCH 3/5] KVM: SVM: Add guest physical address check in NPF interception

[Mohammed Gamal <mgamal@redhat.com>]

Check guest physical address against it's maximum physical memory. If
the guest's physical address exceeds the maximum (i.e. has reserved bits
set), inject a guest page fault with PFERR_RSVD_MASK.

Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
---
 arch/x86/kvm/svm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ad3f5b178a03..facd9b0c9fb0 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2754,6 +2754,13 @@ static int npf_interception(struct vcpu_svm *svm)
 	u64 error_code = svm->vmcb->control.exit_info_1;
 
 	trace_kvm_page_fault(fault_address, error_code);
+
+	/* Check if guest gpa doesn't exceed physical memory limits */
+	if (fault_address >= (1ull << cpuid_maxphyaddr(&svm->vcpu))) {
+		kvm_inject_rsvd_bits_pf(&svm->vcpu, fault_address);
+		return 1;
+	}
+
 	return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code,
 			static_cpu_has(X86_FEATURE_DECODEASSISTS) ?
 			svm->vmcb->control.insn_bytes : NULL,
-- 
2.21.1