From patchwork Wed Oct 8 00:16:21 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 5050761 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1AFB99F30B for ; Wed, 8 Oct 2014 00:16:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 25EC320204 for ; Wed, 8 Oct 2014 00:16:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B14B201F7 for ; Wed, 8 Oct 2014 00:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755412AbaJHAQd (ORCPT ); Tue, 7 Oct 2014 20:16:33 -0400 Received: from mail-pd0-f177.google.com ([209.85.192.177]:37996 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750895AbaJHAQc (ORCPT ); Tue, 7 Oct 2014 20:16:32 -0400 Received: by mail-pd0-f177.google.com with SMTP id v10so5860194pde.36 for ; Tue, 07 Oct 2014 17:16:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=uXs3owXX3zE1oc3q2Mt8knX2odf6FT3gTDdR1svNz/s=; b=ZzpLaCkDkWljxyxAUGvRwGChir/YcIusbgD3RXwh9aAvoV9noFesz3I3J25Bwf7JfK DgrDGykrBMT26Mrt7B6iriC4rF8+y7Y/1Ny+4CW8634m0rfa/nW27xCAGuI1QJO1VG5H N1atyO8kem3jce6h3APVdKfZIkDaMzxDOWs+FfJ6MNVufyvt/KAzmr6n/FyPrUHyLl3Z tcbumJXfDcYzbayZNrJcjlAxGJdUEV1Z36K44tEXcUi7O2P3PaLcYBFYSm0eI6F0oM50 SMkPcrZPHFrlwhds9NsKQMWhkPVmXxcFNW5m3Y2nczBu9gYcnNC8CpD15twSesZvA1cn 4Gjg== X-Gm-Message-State: ALoCoQnNeTVGDSEHtG314PrWA/PdUr04qRmZdhH0xlJxZQvkFGeqc1n2vQNDwk948ORewgoWGzxx X-Received: by 10.66.179.140 with SMTP id dg12mr6701858pac.76.1412727391786; Tue, 07 Oct 2014 17:16:31 -0700 (PDT) Received: from localhost (50-76-60-73-ip-static.hfc.comcastbusiness.net. [50.76.60.73]) by mx.google.com with ESMTPSA id ah2sm17298175pad.10.2014.10.07.17.16.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Oct 2014 17:16:30 -0700 (PDT) From: Andy Lutomirski To: Gleb Natapov , Paolo Bonzini Cc: kvm@vger.kernel.org, Peter Zijlstra , Andy Lutomirski Subject: [PATCH] x86,kvm,vmx: Don't trap writes to CR4.TSD Date: Tue, 7 Oct 2014 17:16:21 -0700 Message-Id: <47a9cf4ebc3fde90fab06d54f32a225db9f0271c.1412727302.git.luto@amacapital.net> X-Mailer: git-send-email 1.9.3 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP CR4.TSD is guest-owned; don't trap writes to it in VMX guests. This avoids a VM exit on context switches into or out of a PR_TSC_SIGSEGV task. I think that this fixes an unintentional side-effect of: 4c38609ac569 KVM: VMX: Make guest cr4 mask more conservative Signed-off-by: Andy Lutomirski --- arch/x86/kvm/vmx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 54ca301f8415..0653233fcc82 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -105,7 +105,7 @@ module_param(nested, bool, S_IRUGO); (KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE) #define KVM_CR4_GUEST_OWNED_BITS \ (X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \ - | X86_CR4_OSXMMEXCPT) + | X86_CR4_OSXMMEXCPT | X86_CR4_TSD) #define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE) #define KVM_RMODE_VM_CR4_ALWAYS_ON (X86_CR4_VME | X86_CR4_PAE | X86_CR4_VMXE)