From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41403) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dT7gH-0002iJ-NK for qemu-devel@nongnu.org; Thu, 06 Jul 2017 10:23:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dT7gG-0005MM-SC for qemu-devel@nongnu.org; Thu, 06 Jul 2017 10:22:57 -0400 References: <149934999661.27.13789728207994914021@f0098f8687cc> From: Paolo Bonzini Message-ID: <1ff791c6-a914-2a26-e5d2-683cacc82b86@redhat.com> Date: Thu, 6 Jul 2017 16:22:37 +0200 MIME-Version: 1.0 In-Reply-To: <149934999661.27.13789728207994914021@f0098f8687cc> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 0/6] block: Add VFIO based driver for NVMe device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, famz@redhat.com Cc: kwolf@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com, keith.busch@intel.com, stefanha@redhat.com, krister@redhat.com On 06/07/2017 16:06, no-reply@patchew.org wrote: > ERROR: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt > #843: FILE: block/nvme.c:40: > + volatile uint32_t *doorbell; > > ERROR: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt > #869: FILE: block/nvme.c:66: > +typedef volatile struct { Indeed volatile should not be necessary, since we use memory barriers appropriately. But these are hardware registers (like, host hardware) so I guess it's okay for this special case. Paolo