From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59010) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ddYnl-0000iO-6s for qemu-devel@nongnu.org; Fri, 04 Aug 2017 05:21:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ddYni-0008Jr-1l for qemu-devel@nongnu.org; Fri, 04 Aug 2017 05:21:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51202) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ddYnh-0008Ip-Rg for qemu-devel@nongnu.org; Fri, 04 Aug 2017 05:21:45 -0400 From: Ladi Prosek Date: Fri, 4 Aug 2017 11:14:03 +0200 Message-Id: <20170804091403.13478-4-lprosek@redhat.com> In-Reply-To: <20170804091403.13478-1-lprosek@redhat.com> References: <20170804091403.13478-1-lprosek@redhat.com> Subject: [Qemu-devel] [PATCH 3/3] i386/kvm: advertise Hyper-V frequency MSRs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, kvm@vger.kernel.org Cc: pbonzini@redhat.com, mtosatti@redhat.com, rkrcmar@redhat.com As of kernel commit eb82feea59d6 ("KVM: hyperv: support HV_X64_MSR_TSC_FREQUENCY and HV_X64_MSR_APIC_FREQUENCY"), KVM supports two new MSRs which are required for nested Hyper-V to read timestamps with RDTSC + TSC page. This commit makes QEMU advertise the MSRs with CPUID.40000003H:EAX[11] and CPUID.40000003H:EDX[8] as specified in the Hyper-V TLFS and experimentally verified on a Hyper-V host. The feature is enabled with the existing hv-time CPU flag, and only if the TSC frequency is stable across migration and known. Signed-off-by: Ladi Prosek --- target/i386/kvm.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 77b6373..7e484a7 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -89,6 +89,7 @@ static bool has_msr_hv_vpindex; static bool has_msr_hv_runtime; static bool has_msr_hv_synic; static bool has_msr_hv_stimer; +static bool has_msr_hv_frequencies; static bool has_msr_xss; static bool has_msr_architectural_pmu; @@ -631,7 +632,17 @@ static int hyperv_handle_properties(CPUState *cs) if (cpu->hyperv_time) { env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_HYPERCALL_AVAILABLE; env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_TIME_REF_COUNT_AVAILABLE; - env->features[FEAT_HYPERV_EAX] |= 0x200; + env->features[FEAT_HYPERV_EAX] |= HV_X64_MSR_REFERENCE_TSC_AVAILABLE; + if (has_msr_hv_frequencies + /* TSC clock must be stable and known for this feature. */ + && ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) + || env->user_tsc_khz != 0) + && env->tsc_khz != 0) { + + env->features[FEAT_HYPERV_EAX] |= HV_X64_ACCESS_FREQUENCY_MSRS; + env->features[FEAT_HYPERV_EDX] |= + HV_FEATURE_FREQUENCY_MSRS_AVAILABLE; + } } if (cpu->hyperv_crash && has_msr_hv_crash) { env->features[FEAT_HYPERV_EDX] |= HV_X64_GUEST_CRASH_MSR_AVAILABLE; @@ -1127,6 +1138,9 @@ static int kvm_get_supported_msrs(KVMState *s) case HV_X64_MSR_STIMER0_CONFIG: has_msr_hv_stimer = true; break; + case HV_X64_MSR_TSC_FREQUENCY: + has_msr_hv_frequencies = true; + break; } } -- 2.9.3