From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42583) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aM016-00077F-Hb for qemu-devel@nongnu.org; Wed, 20 Jan 2016 16:10:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aM013-0000CQ-D0 for qemu-devel@nongnu.org; Wed, 20 Jan 2016 16:10:12 -0500 Received: from mail-wm0-x243.google.com ([2a00:1450:400c:c09::243]:35788) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aM013-0000Bi-5U for qemu-devel@nongnu.org; Wed, 20 Jan 2016 16:10:09 -0500 Received: by mail-wm0-x243.google.com with SMTP id 123so6705676wmz.2 for ; Wed, 20 Jan 2016 13:10:09 -0800 (PST) Sender: Paolo Bonzini References: <1450949580-25759-1-git-send-email-asmetanin@virtuozzo.com> <569DEA3B.2040107@openvz.org> <569F9419.4000601@redhat.com> <569F9D61.5020203@openvz.org> <20160120145218.GH26969@rkaganb.sw.ru> From: Paolo Bonzini Message-ID: <569FF7AE.7060207@redhat.com> Date: Wed, 20 Jan 2016 22:10:06 +0100 MIME-Version: 1.0 In-Reply-To: <20160120145218.GH26969@rkaganb.sw.ru> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v1] kvm/x86: Hyper-V tsc page setup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Roman Kagan , "Denis V. Lunev" , Andrey Smetanin , kvm@vger.kernel.org, Gleb Natapov , qemu-devel@nongnu.org On 20/01/2016 15:52, Roman Kagan wrote: > I think Paolo wanted to be compatible not only with the de facto > implementation in Windows Hyper-V guests, but also with the Linux driver > which followed the buggy spec and thought 0xFFFFFFFF to be invalid. 0xFFFFFFFF is not invalid; it means it is valid but you have to use the MSR. With 0, you cannot use the MSR either and Windows will use the ACPI PM timer or similar. You can see the difference from the result of QueryPerformanceFrequency, IIRC. Paolo