selftests: kvm: test enforcement of paravirtual cpuid features

Add a set of tests that ensure the guest cannot access paravirtual msrs
and hypercalls that have been disabled in the KVM_CPUID_FEATURES leaf.
Expect a #GP in the case of msr accesses and -KVM_ENOSYS from
hypercalls.

Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20201027231044.655110-7-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 66228297ac03..d10c5c05bdf0 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1227,3 +1227,32 @@ void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid)
 			    *data);
 	}
 }
+
+bool set_cpuid(struct kvm_cpuid2 *cpuid,
+	       struct kvm_cpuid_entry2 *ent)
+{
+	int i;
+
+	for (i = 0; i < cpuid->nent; i++) {
+		struct kvm_cpuid_entry2 *cur = &cpuid->entries[i];
+
+		if (cur->function != ent->function || cur->index != ent->index)
+			continue;
+
+		memcpy(cur, ent, sizeof(struct kvm_cpuid_entry2));
+		return true;
+	}
+
+	return false;
+}
+
+uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
+		       uint64_t a3)
+{
+	uint64_t r;
+
+	asm volatile("vmcall"
+		     : "=a"(r)
+		     : "b"(a0), "c"(a1), "d"(a2), "S"(a3));
+	return r;
+}