From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E7567C433F5 for ; Wed, 16 Mar 2022 16:11:04 +0000 (UTC) Received: from localhost ([::1]:44918 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nUWEp-0002YV-MN for qemu-devel@archiver.kernel.org; Wed, 16 Mar 2022 12:11:03 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55330) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nUW9I-0006UP-Ks for qemu-devel@nongnu.org; Wed, 16 Mar 2022 12:05:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:34133) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nUW9F-0007WW-5H for qemu-devel@nongnu.org; Wed, 16 Mar 2022 12:05:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647446712; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=40mFpiyW5EOc2a2/HQ1JYifkGyfHpHBl2YQlQsQJpzk=; b=KnqNTNOeeDwuQr0sbyE37FolwBZm51DEV2tvwooVP1dVRgyA9mnQpIKa+F8UH3Gj3aPQAl 2CQ+j4d8WaqC7B9XRGa32dpG7qgyag1CBBPnHiBV5b5eoRfvb54llUYx+by0jJmC8AAYFf O+mJpb5tWB16N1OIp5WsV2cbiKSP2M4= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-434-nJxqCrIAOEeiiM2YZd1Dgg-1; Wed, 16 Mar 2022 12:05:05 -0400 X-MC-Unique: nJxqCrIAOEeiiM2YZd1Dgg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3CB9F3817484; Wed, 16 Mar 2022 16:05:05 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EDFB3C50943; Wed, 16 Mar 2022 16:05:03 +0000 (UTC) Date: Wed, 16 Mar 2022 16:05:01 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Krempa Subject: Re: [PULL 15/22] x86: Grant AMX permission for guest Message-ID: References: <20220308113445.859669-1-pbonzini@redhat.com> <20220308113445.859669-16-pbonzini@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.1.5 (2021-12-30) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Yang Zhong , Paolo Bonzini , qemu-devel@nongnu.org, Jing Liu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Mar 16, 2022 at 04:57:39PM +0100, Peter Krempa wrote: > On Tue, Mar 08, 2022 at 12:34:38 +0100, Paolo Bonzini wrote: > > From: Yang Zhong > > > > Kernel allocates 4K xstate buffer by default. For XSAVE features > > which require large state component (e.g. AMX), Linux kernel > > dynamically expands the xstate buffer only after the process has > > acquired the necessary permissions. Those are called dynamically- > > enabled XSAVE features (or dynamic xfeatures). > > > > There are separate permissions for native tasks and guests. > > > > Qemu should request the guest permissions for dynamic xfeatures > > which will be exposed to the guest. This only needs to be done > > once before the first vcpu is created. > > > > KVM implemented one new ARCH_GET_XCOMP_SUPP system attribute API to > > get host side supported_xcr0 and Qemu can decide if it can request > > dynamically enabled XSAVE features permission. > > https://lore.kernel.org/all/20220126152210.3044876-1-pbonzini@redhat.com/ > > > > Suggested-by: Paolo Bonzini > > Signed-off-by: Yang Zhong > > Signed-off-by: Jing Liu > > Message-Id: <20220217060434.52460-4-yang.zhong@intel.com> > > Signed-off-by: Paolo Bonzini > > --- > > target/i386/cpu.c | 7 +++++ > > target/i386/cpu.h | 4 +++ > > target/i386/kvm/kvm-cpu.c | 12 ++++---- > > target/i386/kvm/kvm.c | 57 ++++++++++++++++++++++++++++++++++++++ > > target/i386/kvm/kvm_i386.h | 1 + > > 5 files changed, 75 insertions(+), 6 deletions(-) > > With this commit qemu crashes for me when invoking the following > QMP command: It is way worse than that even. If you remove '-S' you get an immediate kaboom on startup on AMD hosts $ ./build/qemu-system-x86_64 -accel kvm Unable to init server: Could not connect: Connection refused qemu-system-x86_64: ../target/i386/kvm/kvm-cpu.c:105: kvm_cpu_xsave_init: Assertion `esa->size == eax' failed. Aborted (core dumped) With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|