From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50788) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1drLOi-0001VW-Qj for qemu-devel@nongnu.org; Mon, 11 Sep 2017 05:52:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1drLOd-0000pd-RT for qemu-devel@nongnu.org; Mon, 11 Sep 2017 05:52:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38192) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1drLOd-0000pC-LM for qemu-devel@nongnu.org; Mon, 11 Sep 2017 05:52:51 -0400 References: <20170807085703.32267-1-lprosek@redhat.com> From: Paolo Bonzini Message-ID: Date: Mon, 11 Sep 2017 11:52:43 +0200 MIME-Version: 1.0 In-Reply-To: <20170807085703.32267-1-lprosek@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 0/4] i386/kvm: advertise Hyper-V frequency MSRs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ladi Prosek , qemu-devel@nongnu.org, kvm@vger.kernel.org Cc: mtosatti@redhat.com, david@redhat.com, rkrcmar@redhat.com On 07/08/2017 10:56, Ladi Prosek wrote: > This is the QEMU part of the changes required for nested Hyper-V to read > timestamps with RDTSC + TSC page. Without exposing the frequency MSRs, > Windows with the Hyper-V role enabled use the much slower > HV_X64_MSR_TIME_REF_COUNT (0x40000020) RDMSR to read timestamps. > > The new registers are exposed only if the TSC frequency is stable across > migration and known, as suggested by Paolo. > > v1->v2: > * deleted an extra empty line in patch 1 > * added patch 3 introducing a helper function for the "TSC is stable and > known" check (David) > > Ladi Prosek (4): > i386/kvm: use a switch statement for MSR detection > i386/kvm: set tsc_khz before configuring Hyper-V CPUID > i386/kvm: introduce tsc_is_stable_and_known() > i386/kvm: advertise Hyper-V frequency MSRs > > target/i386/kvm.c | 138 ++++++++++++++++++++++++++++-------------------------- > 1 file changed, 71 insertions(+), 67 deletions(-) > Queued, thanks. Paolo