kvm: add support for reading tsc frequency via cpuid.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20200310102248.28412-3-kraxel@redhat.com

diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index ef420931b9a5aae1f403cff9b44d28a651272b9b..1e3d6012700b4b9e0326100c3ae2d395b403df87 100644 (file)
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -67,6 +67,11 @@ static void kvm_detect(void)
     if (strcmp(signature, "KVMKVMKVM") == 0) {
         dprintf(1, "Running on KVM\n");
         PlatformRunningOn |= PF_KVM;
+        if (eax >= KVM_CPUID_SIGNATURE + 0x10) {
+            cpuid(KVM_CPUID_SIGNATURE + 0x10, &eax, &ebx, &ecx, &edx);
+            dprintf(1, "kvm: have invtsc, freq %u kHz\n", eax);
+            tsctimer_setfreq(eax, "invtsc");
+        }
     }
 }