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 6EEFBC433F5 for ; Wed, 23 Mar 2022 12:49:37 +0000 (UTC) Received: from localhost ([::1]:39586 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nX0Qi-0005ox-HE for qemu-devel@archiver.kernel.org; Wed, 23 Mar 2022 08:49:36 -0400 Received: from eggs.gnu.org ([209.51.188.92]:43918) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWzWd-0004Fh-Iz for qemu-devel@nongnu.org; Wed, 23 Mar 2022 07:51:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:55203) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWzWb-00046w-F3 for qemu-devel@nongnu.org; Wed, 23 Mar 2022 07:51:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648036293; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tkKwmFwqNBo6pAux6I3M9nhVT4fWgWcED5VfR5NPMmA=; b=ejZf4dEsj33ZVAiEfU7GTYCri8l5BW+kmn+BbG8koeg+XkOXoP2XFtWDmK/AaUL5AizJMv /fUT5Y/6v/QcU/CSEVuvzr4AFqp8xxe8v4+qWEbRwQHhH8r4O9VoC4+YmBdivZUknNhZ6P nV5PnePskHAftQaeZ+SgKOpTRwZid98= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-388-XTroCT2TO_i0h64gwkiiQg-1; Wed, 23 Mar 2022 07:51:25 -0400 X-MC-Unique: XTroCT2TO_i0h64gwkiiQg-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 5DAB2185A79C; Wed, 23 Mar 2022 11:51:25 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9ED81C15D49; Wed, 23 Mar 2022 11:51:24 +0000 (UTC) Date: Wed, 23 Mar 2022 11:51:22 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Paolo Bonzini Subject: Re: [PATCH] KVM: x86: workaround invalid CPUID[0xD,9] info on some AMD processors Message-ID: References: <20220323114315.22594-1-pbonzini@redhat.com> MIME-Version: 1.0 In-Reply-To: <20220323114315.22594-1-pbonzini@redhat.com> 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 Content-Transfer-Encoding: 8bit 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 , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Mar 23, 2022 at 12:43:15PM +0100, Paolo Bonzini wrote: > Some AMD processors expose the PKRU extended save state even if they do not have > the related PKU feature in CPUID. Worse, when they do they report a size of > 64, whereas the expected size of the PKRU extended save state is 8, therefore > the esa->size == eax assertion does not hold. > > The state is already ignored by KVM_GET_SUPPORTED_CPUID because it > was not enabled in the host XCR0. However, QEMU kvm_cpu_xsave_init() > runs before QEMU invokes arch_prctl() to enable dynamically-enabled > save states such as XTILEDATA, and KVM_GET_SUPPORTED_CPUID hides save > states that have yet to be enabled. Therefore, kvm_cpu_xsave_init() > needs to consult the host CPUID instead of KVM_GET_SUPPORTED_CPUID, > and dies with an assertion failure. > > When setting up the ExtSaveArea array to match the host, ignore features that > KVM does not report as supported. This will cause QEMU to skip the incorrect > CPUID leaf instead of tripping the assertion. Closes: https://gitlab.com/qemu-project/qemu/-/issues/916 > > Reported-by: Daniel P. Berrangé Also credit Reported-by: Peter Krempa > Analyzed-by: Yang Zhong > Signed-off-by: Paolo Bonzini > --- > target/i386/cpu.c | 4 ++-- > target/i386/cpu.h | 2 ++ > target/i386/kvm/kvm-cpu.c | 19 ++++++++++++------- > 3 files changed, 16 insertions(+), 9 deletions(-) Tested-by: Daniel P. Berrangé no longer crashes on the AMD machine I have to hand. 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 :|