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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46702 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kIv9R-0008E7-Dg for qemu-devel@archiver.kernel.org; Thu, 17 Sep 2020 10:44:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49216) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kIv7j-0006wv-Et for qemu-devel@nongnu.org; Thu, 17 Sep 2020 10:42:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47240) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kIv7h-0006jA-Ay for qemu-devel@nongnu.org; Thu, 17 Sep 2020 10:42:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600353776; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; 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auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/17 02:01:40 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.997, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Antoine Damhet , Paolo Bonzini , Marcelo Tosatti , qemu-devel@nongnu.org, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Vitaly Kuznetsov (vkuznets@redhat.com) wrote: > Antoine Damhet writes: > > > On Thu, Sep 17, 2020 at 01:13:06PM +0200, Vitaly Kuznetsov wrote: > >> QEMU's kvmclock device is only created when KVM PV feature bits for > >> kvmclock (KVM_FEATURE_CLOCKSOURCE/KVM_FEATURE_CLOCKSOURCE2) are > >> exposed to the guest. With 'kvm=off' cpu flag the device is not > >> created and we don't call KVM_GET_CLOCK/KVM_SET_CLOCK upon migration. > >> It was reported that without these call at least Hyper-V TSC page > >> clocksouce (which can be enabled independently) gets broken after > >> migration. > >> > >> Switch to creating kvmclock QEMU device unconditionally, it seems > >> to always make sense to call KVM_GET_CLOCK/KVM_SET_CLOCK on migration. > >> Use KVM_CAP_ADJUST_CLOCK check instead of CPUID feature bits. > >> > >> Reported-by: Antoine Damhet > >> Suggested-by: Paolo Bonzini > >> Signed-off-by: Vitaly Kuznetsov > >> --- > >> hw/i386/kvm/clock.c | 6 +----- > >> target/i386/kvm.c | 5 +++++ > >> target/i386/kvm_i386.h | 1 + > >> 3 files changed, 7 insertions(+), 5 deletions(-) > >> > >> diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c > >> index 64283358f91d..526c9ea5172b 100644 > >> --- a/hw/i386/kvm/clock.c > >> +++ b/hw/i386/kvm/clock.c > >> @@ -330,11 +330,7 @@ static const TypeInfo kvmclock_info = { > >> /* Note: Must be called after VCPU initialization. */ > >> void kvmclock_create(void) > >> { > >> - X86CPU *cpu = X86_CPU(first_cpu); > >> - > >> - if (kvm_enabled() && > >> - cpu->env.features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) | > >> - (1ULL << KVM_FEATURE_CLOCKSOURCE2))) { > >> + if (kvm_enabled() && kvm_has_adjust_clock()) { > > > > Shouldn't the old check used when machine type <= 5.1 in order to avoid > > migration incompatibility ? > > Hm, when the check fails we just don't create the device and no error is > reported, so even if we have kvmclock data in the migration stream but > fail to create it migration will still succeed, right? (not a migration > expert here :-) When the migration stream is parsed, it'll try and find a "kvmclock" device to pass the data it's reading to; if one doesn't exist it'll fail. The other question is in the incoming direction from an older VM; you'll have a kvm clock created here, but you won't load the kvm clock state from the migration stream - what is this clock going to do? Dave > > > >> sysbus_create_simple(TYPE_KVM_CLOCK, -1, NULL); > >> } > >> } > >> diff --git a/target/i386/kvm.c b/target/i386/kvm.c > >> index 4a8b3a41c1bc..20b31b65307b 100644 > >> --- a/target/i386/kvm.c > >> +++ b/target/i386/kvm.c > >> @@ -143,6 +143,11 @@ bool kvm_has_adjust_clock_stable(void) > >> return (ret == KVM_CLOCK_TSC_STABLE); > >> } > >> > >> +bool kvm_has_adjust_clock(void) > >> +{ > >> + return kvm_check_extension(kvm_state, KVM_CAP_ADJUST_CLOCK); > >> +} > >> + > >> bool kvm_has_exception_payload(void) > >> { > >> return has_exception_payload; > >> diff --git a/target/i386/kvm_i386.h b/target/i386/kvm_i386.h > >> index 064b8798a26c..0fce4e51d2d6 100644 > >> --- a/target/i386/kvm_i386.h > >> +++ b/target/i386/kvm_i386.h > >> @@ -34,6 +34,7 @@ > >> > >> bool kvm_allows_irq0_override(void); > >> bool kvm_has_smm(void); > >> +bool kvm_has_adjust_clock(void); > >> bool kvm_has_adjust_clock_stable(void); > >> bool kvm_has_exception_payload(void); > >> void kvm_synchronize_all_tsc(void); > >> -- > >> 2.25.4 > >> > >> > > -- > Vitaly > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK