From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: [PATCHv2 0/3] x86: workaround inability to fully restore FPU state Date: Tue, 23 Feb 2016 11:05:36 +0000 Message-ID: <1456225539-9162-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aYAmr-00085h-8c for xen-devel@lists.xenproject.org; Tue, 23 Feb 2016 11:05:49 +0000 List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: Andrew Cooper , David Vrabel , Jan Beulich List-Id: xen-devel@lists.xenproject.org This series extends the workaround for the inability for some x86 CPUs to fully restore the FPU exception state (64-bit FIP/FDP and FCS/FDS). Toolstack (or the guest) may override the default behaviour to always do a 32-bit save/restore. Running Microsoft's Driver Verifier continues to work in a 32-bit Windows guest and (if HVM_PARAM_X87_FIP_WIDTH is set to 4) now works in a 64-bit Windows guest. Changes in v2: - Improve xsave()'s detection of whether the hardware updated FIP/FDP. - Leave 64-bit PV guests in auto mode. - Don't automatically set FIP width for Windows guests -- it's safer to leave auto-mode on and leave it up to the admin to enable the mode when running Driver Verifier. - Use a HVM param to change the default. David