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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5FDAC433FE for ; Wed, 9 Nov 2022 15:20:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231909AbiKIPUN (ORCPT ); Wed, 9 Nov 2022 10:20:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232013AbiKIPUH (ORCPT ); Wed, 9 Nov 2022 10:20:07 -0500 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF8841D677 for ; Wed, 9 Nov 2022 07:20:05 -0800 (PST) Received: by mail-pl1-x635.google.com with SMTP id b21so17374593plc.9 for ; Wed, 09 Nov 2022 07:20:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=x9teoJ5wje0VkvVwfbh872sgK0WyIimofXUzASdDvqA=; b=SHtyJHGvJeg5P42AZAxJL4cIAhjRarkT+Cu6YbFyPk9onbab5/HQtm1iHGWnZlR61s afoyV/6v11Ql85YbQFKudmE5nQSMHREIGmM3Nvo6jh7OVUVSh8LzTUt3IkGJXwmKqKT6 WRafW2EzCe146gR5GvJj72BUidMgPVoF+yEWGt0c7TkGTPWaf1rGAfboRncdC5tHxa1R g3rg7fPIjGpHYKgCGG+AnwUVo6RCvczl/5KW4eRQHkSiBb0ZPjjXpV7NK8Hv1CZUBgEL 2ecpbyBnzlU7lbJVbTKuVSMyO2e10d7gKMGfZx2UimOIYgvU2KpzV5LTwUy8l7jFFihw yAZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=x9teoJ5wje0VkvVwfbh872sgK0WyIimofXUzASdDvqA=; b=t/B1vPSh86ABz0MFfklOz7B4qPO2KURjrhAHmZAlTG5UFi/nQ0g7eoohF7GAwhZudc Q7+GWNd5yG2SxFyLo7cGZQ4FjqKFC/SD49rTckvyz/HmDCCg5HbeVRcy3T8bC6EanMy8 t75saNVU/PR7LUG59ndE1/Sfey2Qc3Nuu7TmsraIme2D6DUnzJ6GbH7wR4iRYZFNraoZ 0az/V4RwpaoU3tU4APxlE4mU6qS9oO3t0R48GlgR2BEIT/EHNsxs238TjbqE91DGw7xv MMh8KYbGmrE3/jBKGUFd1bTSad4MmLZBM782Jceo0iAfnin/pBh0XIjvS8JMKsKclDsx s5Ug== X-Gm-Message-State: ACrzQf20vYyt9UHWVvJyaJ0VyvUQKyhn+FD5mGYh3DbCBbUdiQEShIZT OJgQiTJIaXHqpQ4ukl48okcd6Q== X-Google-Smtp-Source: AMsMyM4boMHPt76cAxey5Fe/JfDpSNTYBXnZkeYQ19CkhPccng6LpwJObfa7wg8zMbWlv4QcuAmfNw== X-Received: by 2002:a17:902:ab89:b0:186:7cfc:cde8 with SMTP id f9-20020a170902ab8900b001867cfccde8mr62403327plr.9.1668007205217; Wed, 09 Nov 2022 07:20:05 -0800 (PST) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id y15-20020a1709027c8f00b0017854cee6ebsm9219777pll.72.2022.11.09.07.20.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Nov 2022 07:20:04 -0800 (PST) Date: Wed, 9 Nov 2022 15:20:01 +0000 From: Sean Christopherson To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, thomas.lendacky@amd.com, jmattson@google.com, stable@vger.kernel.org Subject: Re: [PATCH 03/11] KVM: SVM: adjust register allocation for __svm_vcpu_run Message-ID: References: <20221109145156.84714-1-pbonzini@redhat.com> <20221109145156.84714-4-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221109145156.84714-4-pbonzini@redhat.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Nov 09, 2022, Paolo Bonzini wrote: > In preparation for moving vmload/vmsave to __svm_vcpu_run, __svm_vcpu_run() > keep the pointer to the struct vcpu_svm in %rdi. This way > it is possible to load svm->vmcb01.pa in %rax without > clobbering the pointer to svm itself. If you feel like doing fixup before pushing, add a note to call out that avoiding RAX will also be "necessary" to play nice with loading/storing MSR_SPEC_CTRL? When fiddling with this code, I found the RDMSR/WRMSR clobbers to be far more problematic than the VMCB pointers. > No functional change intended. > > Cc: stable@vger.kernel.org > Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") > Signed-off-by: Paolo Bonzini Reviewed-by: Sean Christopherson