selftests: kvm/x86: Parameterize the CPUID vendor string check

Refactor is_intel_cpu() to make it easier to reuse the bulk of the
code for other vendors in the future.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220115052431.447232-3-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/lib/x86_64/processor.c

@@ -1253,10 +1253,10 @@ void kvm_x86_state_cleanup(struct kvm_x86_state *state)
 	free(state);
 }
 
-bool is_intel_cpu(void)
+static bool cpu_vendor_string_is(const char *vendor)
 {
+	const uint32_t *chunk = (const uint32_t *)vendor;
 	int eax, ebx, ecx, edx;
-	const uint32_t *chunk;
 	const int leaf = 0;
 
 	__asm__ __volatile__(
@@ -1265,10 +1265,14 @@ bool is_intel_cpu(void)
 		  "=c"(ecx), "=d"(edx)
 		: /* input */ "0"(leaf), "2"(0));
 
-	chunk = (const uint32_t *)("GenuineIntel");
 	return (ebx == chunk[0] && edx == chunk[1] && ecx == chunk[2]);
 }
 
+bool is_intel_cpu(void)
+{
+	return cpu_vendor_string_is("GenuineIntel");
+}
+
 uint32_t kvm_get_cpuid_max_basic(void)
 {
 	return kvm_get_supported_cpuid_entry(0)->eax;