From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43499) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezMH1-0002dh-31 for qemu-devel@nongnu.org; Fri, 23 Mar 2018 08:58:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ezMGz-00017Q-1F for qemu-devel@nongnu.org; Fri, 23 Mar 2018 08:58:23 -0400 From: Roman Kagan Date: Fri, 23 Mar 2018 15:58:08 +0300 Message-Id: <20180323125808.4479-3-rkagan@virtuozzo.com> In-Reply-To: <20180323125808.4479-1-rkagan@virtuozzo.com> References: <20180323125808.4479-1-rkagan@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH for-2.12 2/2] i386/hyperv: error out if features requested but unsupported List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, Paolo Bonzini , Eduardo Habkost , Vitaly Kuznetsov Cc: qemu-stable@nongnu.org In order to guarantee compatibility on migration, QEMU should have complete control over the features it announces to the guest via CPUID. However, for a number of Hyper-V-related cpu properties, if the corresponding feature is not supported by the underlying KVM, the propery is silently ignored and the feature is not announced to the guest. Refuse to start with an error instead. Cc: qemu-stable@nongnu.org Signed-off-by: Roman Kagan --- target/i386/kvm.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index fb20ff18c2..c9c359241c 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -658,17 +658,34 @@ static int hyperv_handle_properties(CPUState *cs) env->features[FEAT_HYPERV_EAX] |= HV_ACCESS_FREQUENCY_MSRS; env->features[FEAT_HYPERV_EDX] |= HV_FREQUENCY_MSRS_AVAILABLE; } - if (cpu->hyperv_crash && has_msr_hv_crash) { + if (cpu->hyperv_crash) { + if (!has_msr_hv_crash) { + fprintf(stderr, + "Hyper-V crash MSRs are not supported by kernel\n"); + return -ENOSYS; + } env->features[FEAT_HYPERV_EDX] |= HV_GUEST_CRASH_MSR_AVAILABLE; } env->features[FEAT_HYPERV_EDX] |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE; - if (cpu->hyperv_reset && has_msr_hv_reset) { + if (cpu->hyperv_reset) { + if (!has_msr_hv_reset) { + fprintf(stderr, "Hyper-V reset MSR is not supported by kernel\n"); + return -ENOSYS; + } env->features[FEAT_HYPERV_EAX] |= HV_RESET_AVAILABLE; } - if (cpu->hyperv_vpindex && has_msr_hv_vpindex) { + if (cpu->hyperv_vpindex) { + if (!has_msr_hv_vpindex) { + fprintf(stderr, "Hyper-V VP_INDEX is not supported by kernel\n"); + return -ENOSYS; + } env->features[FEAT_HYPERV_EAX] |= HV_VP_INDEX_AVAILABLE; } - if (cpu->hyperv_runtime && has_msr_hv_runtime) { + if (cpu->hyperv_runtime) { + if (!has_msr_hv_runtime) { + fprintf(stderr, "Hyper-V VP_INDEX is not supported by kernel\n"); + return -ENOSYS; + } env->features[FEAT_HYPERV_EAX] |= HV_VP_RUNTIME_AVAILABLE; } if (cpu->hyperv_synic) { -- 2.14.3