KVM: selftests: hyperv_cpuid: add check for NoNonArchitecturalCoreSharing bit

The bit is supposed to be '1' when SMT is not supported or forcefully
disabled and '0' otherwise.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c
index ee59831fbc98..443a2b54645b 100644
--- a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c
+++ b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c
@@ -26,6 +26,25 @@ static void guest_code(void)
 {
 }
 
+static int smt_possible(void)
+{
+        char buf[16];
+        FILE *f;
+        bool res = 1;
+
+        f = fopen("/sys/devices/system/cpu/smt/control", "r");
+        if (f) {
+                if (fread(buf, sizeof(*buf), sizeof(buf), f) > 0) {
+                        if (!strncmp(buf, "forceoff", 8) ||
+                            !strncmp(buf, "notsupported", 12))
+                                res = 0;
+                }
+                fclose(f);
+        }
+
+        return res;
+}
+
 static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries,
                           int evmcs_enabled)
 {
@@ -59,6 +78,14 @@ static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries,
                 TEST_ASSERT(!entry->padding[0] && !entry->padding[1] &&
                             !entry->padding[2], "padding should be zero");
 
+                if (entry->function == 0x40000004) {
+                        int nononarchcs = !!(entry->eax & (1UL << 18));
+
+                        TEST_ASSERT(nononarchcs == !smt_possible(),
+                                    "NoNonArchitecturalCoreSharing bit"
+                                    " doesn't reflect SMT setting");
+                }
+
                 /*
                  * If needed for debug:
                  * fprintf(stdout,