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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADEF9C19759 for ; Thu, 1 Aug 2019 14:43:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BED72080C for ; Thu, 1 Aug 2019 14:43:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728931AbfHAOnK (ORCPT ); Thu, 1 Aug 2019 10:43:10 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:38548 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726583AbfHAOnJ (ORCPT ); Thu, 1 Aug 2019 10:43:09 -0400 Received: by mail-wm1-f67.google.com with SMTP id s15so42096323wmj.3 for ; Thu, 01 Aug 2019 07:43:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=AQVZzxviCSRzfupMACZrSRSzcwDwgjm3ki6dTQwgdSY=; b=DIp1dtX6V/i6+j/4xRLbAJFimuOiPdH+j6SAQNJswosUb5aJNhPrMeGuG1Hr2hRNS/ Yo49Vq4DWh5MEPRLh1vKNLr2xCPB6uIRp9nkMjex7gXsacb75Nn0yHW54S3PPqiXXyWL 8CZevZnq/AcZCosuTrsZ0E8238QT1zaj1VOqUvsQjk18ss6rpw9kH0ktkNsYNyEM7eMk bRedTX//kpfIyZvgt9JBFy8mDEjSchS2UZFwHP4liJkrtZPZZXy3p0feLVM1e7+uIP0A l4HQsTIEcI+5uWQ/e1fVdLoFvUaO7JTO2ftEHevH/jDOZTzowkA9WBlolvgSodFcEVKq FhnQ== X-Gm-Message-State: APjAAAVVE4Vb6Z+3kTdEJw0aTlpwuQUfrghObLC7OnwXr3ikO1RH9wwR qOWfNPeRWcQ5jxQUZrqK5pLhxw== X-Google-Smtp-Source: APXvYqyvHJ4XFkD6+G+k8opm3OHCmgXq7DQbrlYYAWG0VPhgFif8OCAYnGiM6GkBJFvf5mNzeQpPPQ== X-Received: by 2002:a1c:5602:: with SMTP id k2mr109441102wmb.173.1564670587902; Thu, 01 Aug 2019 07:43:07 -0700 (PDT) Received: from vitty.brq.redhat.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id f204sm111394043wme.18.2019.08.01.07.43.06 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 01 Aug 2019 07:43:06 -0700 (PDT) From: Vitaly Kuznetsov To: Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Joerg Roedel , Jim Mattson Subject: Re: [PATCH 3/5] x86: KVM: svm: clear interrupt shadow on all paths in skip_emulated_instruction() In-Reply-To: <20190801141802.GA6783@linux.intel.com> References: <20190801051418.15905-1-vkuznets@redhat.com> <20190801051418.15905-4-vkuznets@redhat.com> <20190801141802.GA6783@linux.intel.com> Date: Thu, 01 Aug 2019 16:43:05 +0200 Message-ID: <87ftml54li.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sean Christopherson writes: > On Thu, Aug 01, 2019 at 07:14:16AM +0200, Vitaly Kuznetsov wrote: >> Regardless of the way how we skip instruction, interrupt shadow needs to be >> cleared. >> >> Signed-off-by: Vitaly Kuznetsov >> Reviewed-by: Jim Mattson >> --- >> arch/x86/kvm/svm.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >> index 80f576e05112..7c7dff3f461f 100644 >> --- a/arch/x86/kvm/svm.c >> +++ b/arch/x86/kvm/svm.c >> @@ -784,13 +784,15 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu) >> EMULATE_DONE) >> pr_err_once("KVM: %s: unable to skip instruction\n", >> __func__); >> - return; >> + goto clear_int_shadow; > > A better fix would be to clear the interrupt shadow in x86_emulate_instruction() > after updating RIP for EMULTYPE_SKIP. VMX has this same flaw when running > nested as handle_ept_misconfig() also expects the interrupt shadow to be > handled by kvm_emulate_instruction(). Clearing the shadow if and only if > the skipping is successful also means KVM isn't incorrectly zapping the > shadow when emulation fails. Oh, nice catch actually! Will do in v2. -- Vitaly