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[94.36.194.48]) by smtp.gmail.com with ESMTPSA id 24sm16286180wrt.60.2018.04.06.10.11.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Apr 2018 10:11:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=X3usq5wxuXxZEl1xo4nXHUEEX0X157f3d2lhCVoNRP0=; b=pPOLfLsyTbPvAPcTMdbSrittjiEw5NH3DrNqjCVvlC8q8VFwmNfCLxA2W5j0haYE/T 9QrtYupqM9HVjRqDxZpZ7znGVX3bNU9RGDrimRrPtFcC0rMiC4LFgOw03Nz8UWCXIkEh 5yj6gI4g+1MQAr7JCp0oPS9UbuFPTIzfYNx/Z2w7rzz0EbDQHZK8vDlrTENu1Mz2S2mM Icc1v+itIoZ3rxC8QbJkrEXve4MVzSG5hH62zH2Gc+Oel7sPMsLp5fsbTQ3zKWL1dC8J 9/0r/PZ7eEhUMbf4/V6DT9ICeXBtvIKKAOVPPD2fzM9fSmM9VSXbLX5s9t7GfSYzID6M wZmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=X3usq5wxuXxZEl1xo4nXHUEEX0X157f3d2lhCVoNRP0=; b=Vx+MSx9jg4DHLoZ2JwGXfYvbFvaopT6wtDa43qyDs6FDkMty7xfTuIHDfkFiVKcQiv Pmstr3D0/rjy7x1tx21mPABD/AIdChQ7he6T9VrX2QltFJy3J0GMjj5yZeZkEJCe7d6y Yw6kvHTxBwrP/F7ngfi2uSGmi75v/9b5dCDJUV8VqpzzC3JJ76k3F5IKVtdBfcYuebi7 zm1Wmg0u/1LXS3e6h01ed+YJhMwC0DbXej51VXoVQJNqdUN7/0zVoDXwCF7fZ4g+Fw7c JVxxkTy1EgGREiAhew575rIhfRtHTElKVW1Ez/D5QIfvZe3qmkmGZzXVKdkwGKTOLs1r cBhw== X-Gm-Message-State: AElRT7ELh8sZ74qtumTXxFXT/L+6j03HU4M2j75Nm1Gul4YXAe5oOHcC vEFUc8J4/nRaDqM1+VMHeg1my/CC X-Google-Smtp-Source: AIpwx4/bAC6TMTwMZ580683MmHODWbIPwBW9p+7xb2CmbK7pTZFEXpvdzkJHzdRC/ij8QBlwyxJDog== X-Received: by 10.223.195.58 with SMTP id n55mr18291571wrf.132.1523034702115; Fri, 06 Apr 2018 10:11:42 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Fri, 6 Apr 2018 19:11:14 +0200 Message-Id: <1523034681-33787-14-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1523034681-33787-1-git-send-email-pbonzini@redhat.com> References: <1523034681-33787-1-git-send-email-pbonzini@redhat.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:400c:c0c::235 Subject: [Qemu-devel] [PULL 13/20] kvmclock: fix clock_is_reliable on migration from QEMU < 2.9 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michael Chapman Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Michael Chapman When migrating from a pre-2.9 QEMU, no clock_is_reliable flag is transferred. We should assume that the source host has an unreliable KVM_GET_CLOCK, rather than using whatever was determined locally, to ensure that any drift from the TSC-based value calculated by the guest is corrected. Signed-off-by: Michael Chapman Message-Id: <20180406053406.774-1-mike@very.puzzling.org> Signed-off-by: Paolo Bonzini --- hw/i386/kvm/clock.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c index 1707434..7dac319 100644 --- a/hw/i386/kvm/clock.c +++ b/hw/i386/kvm/clock.c @@ -242,6 +242,19 @@ static const VMStateDescription kvmclock_reliable_get_= clock =3D { }; =20 /* + * When migrating, assume the source has an unreliable + * KVM_GET_CLOCK unless told otherwise. + */ +static int kvmclock_pre_load(void *opaque) +{ + KVMClockState *s =3D opaque; + + s->clock_is_reliable =3D false; + + return 0; +} + +/* * When migrating, read the clock just before migration, * so that the guest clock counts during the events * between: @@ -268,6 +281,7 @@ static const VMStateDescription kvmclock_vmsd =3D { .name =3D "kvmclock", .version_id =3D 1, .minimum_version_id =3D 1, + .pre_load =3D kvmclock_pre_load, .pre_save =3D kvmclock_pre_save, .fields =3D (VMStateField[]) { VMSTATE_UINT64(clock, KVMClockState), --=20 1.8.3.1