From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37228) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f47BF-0007F3-Jk for qemu-devel@nongnu.org; Thu, 05 Apr 2018 11:52:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f47BE-0003iU-PQ for qemu-devel@nongnu.org; Thu, 05 Apr 2018 11:52:05 -0400 Received: from mail-wr0-x241.google.com ([2a00:1450:400c:c0c::241]:43986) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1f47BE-0003iK-EV for qemu-devel@nongnu.org; Thu, 05 Apr 2018 11:52:04 -0400 Received: by mail-wr0-x241.google.com with SMTP id p53so29229555wrc.10 for ; Thu, 05 Apr 2018 08:52:04 -0700 (PDT) Sender: Paolo Bonzini References: <20180330170209.20627-1-rkagan@virtuozzo.com> From: Paolo Bonzini Message-ID: <84d1f39e-856b-5f5c-0352-37554b825f55@redhat.com> Date: Thu, 5 Apr 2018 17:52:00 +0200 MIME-Version: 1.0 In-Reply-To: <20180330170209.20627-1-rkagan@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.12 v3 0/2] i386/hyperv: fully control Hyper-V features in CPUID List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Roman Kagan , qemu-devel@nongnu.org, Eduardo Habkost , Vitaly Kuznetsov On 30/03/2018 19:02, Roman Kagan wrote: > In order to guarantee compatibility on migration, QEMU should have > complete control over the features it announces to the guest via CPUID. > > However, a number of Hyper-V-related features happen to depend on the > support in the underlying KVM, with no regard to QEMU configuration. > > Make QEMU regain control over what Hyper-V features it announces to the > guest. > > Note #1: the patches are also being proposed[*] for stable-2.11, even > though one of them introduces a new cpu property. This is done to > minimize the number of published QEMU releases where the behavior of the > features is unpredictable, with potentially fatal consequences for the > guest. > > Note #2: there are other problems in the surrounding code, like ugly > error reporting or inconsistent population of MSRs. I think this can be > put off to post-2.12. > > [*] for the stable branch the second patch will have error returns > replaced with warnings; I'll post a separate series. > > v2 -> v3: > - include the fix for 'hv-time' missed previously > > v1 -> v2: > - indicate what flag requested the feature that can't be enabled in the > error message > - fix a typo in the error message for VP_RUNTIME Queued, thanks. Paolo > > Roman Kagan (2): > i386/hyperv: add hv-frequencies cpu property > i386/hyperv: error out if features requested but unsupported > > target/i386/cpu.h | 1 + > target/i386/cpu.c | 1 + > target/i386/kvm.c | 56 ++++++++++++++++++++++++++++++++++++++++++------------- > 3 files changed, 45 insertions(+), 13 deletions(-) >