From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38438) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJ08z-0005Uh-PO for qemu-devel@nongnu.org; Mon, 09 Sep 2013 08:00:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VJ08t-0001E9-HL for qemu-devel@nongnu.org; Mon, 09 Sep 2013 08:00:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42355) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJ08t-0001Cv-0d for qemu-devel@nongnu.org; Mon, 09 Sep 2013 08:00:31 -0400 Message-ID: <522DB84E.2080009@redhat.com> Date: Mon, 09 Sep 2013 14:00:14 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1378386382-415-1-git-send-email-pbonzini@redhat.com> <1378386382-415-3-git-send-email-pbonzini@redhat.com> <20130908115205.GG17294@redhat.com> <522D8C2E.1030601@redhat.com> <20130909091804.GN17294@redhat.com> <522D99CB.2030503@redhat.com> <20130909104155.GP17294@redhat.com> In-Reply-To: <20130909104155.GP17294@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH uq/master 2/2] KVM: make XSAVE support more robust List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, ehabkost@redhat.com Il 09/09/2013 12:41, Gleb Natapov ha scritto: >>>> In fact, perhaps even XSTATE_SUPPORTED is not restrictive enough here, >>>> and we should hide all features that are not visible in CPUID. It is >>>> okay, however, to test it in cpu_post_load. >>> >>> The kernel should not even return state that is not visible in CPUID. >> >> That's an interesting point of view that I hadn't considered. But just >> like you asked me why it should return state that is not visible in >> CPUID, I'm asking you why it should not... >> > For number of reasons. First because since a sate is not used there is no > point in migrating it. Second to make interface more deterministic for > QEMU. i.e QEMU configures only features it supports and gets > exactly same state from the kernel no matter what host cpu is and what > kernel version is. This patch will not be needed since kernel will do > the job. Good reasons, thanks. Let's do it in the kernel then and avoid this patch altogether. Paolo