From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57117) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ewsid-0005dS-0t for qemu-devel@nongnu.org; Fri, 16 Mar 2018 13:00:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ewsiX-0005Xc-J0 for qemu-devel@nongnu.org; Fri, 16 Mar 2018 13:00:39 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55936 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ewsiX-0005X9-Fg for qemu-devel@nongnu.org; Fri, 16 Mar 2018 13:00:33 -0400 From: Vitaly Kuznetsov Date: Fri, 16 Mar 2018 18:00:20 +0100 Message-Id: <20180316170020.8212-3-vkuznets@redhat.com> In-Reply-To: <20180316170020.8212-1-vkuznets@redhat.com> References: <20180316170020.8212-1-vkuznets@redhat.com> Subject: [Qemu-devel] [PATCH v2 2/2] i386/kvm: lower requirements for Hyper-V frequency MSRs exposure List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Richard Henderson , Eduardo Habkost , Marcelo Tosatti , qemu-devel@nongnu.org, Roman Kagan Requiring tsc_is_stable_and_known() is too restrictive: even without INVTCS nested Hyper-V-on-KVM enables TSC pages for its guests e.g. when Reenlightenment MSRs are present. Presence of frequency MSRs doesn't mean these frequencies are stable, it just means they're available for reading. Signed-off-by: Vitaly Kuznetsov --- target/i386/kvm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/i386/kvm.c b/target/i386/kvm.c index accf50eac3..a6d1210f46 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -650,7 +650,7 @@ static int hyperv_handle_properties(CPUState *cs) env->features[FEAT_HYPERV_EAX] |= HV_TIME_REF_COUNT_AVAILABLE; env->features[FEAT_HYPERV_EAX] |= HV_REFERENCE_TSC_AVAILABLE; - if (has_msr_hv_frequencies && tsc_is_stable_and_known(env)) { + if (has_msr_hv_frequencies && env->tsc_khz) { env->features[FEAT_HYPERV_EAX] |= HV_ACCESS_FREQUENCY_MSRS; env->features[FEAT_HYPERV_EDX] |= HV_FREQUENCY_MSRS_AVAILABLE; } -- 2.14.3