From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42502) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agXkh-0003TJ-AJ for qemu-devel@nongnu.org; Thu, 17 Mar 2016 09:14:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1agXkd-00042K-9F for qemu-devel@nongnu.org; Thu, 17 Mar 2016 09:14:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43600) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agXkd-00042G-4S for qemu-devel@nongnu.org; Thu, 17 Mar 2016 09:14:07 -0400 References: <20160308183050.GJ2049@HEDWIG.INI.CMU.EDU> <20160316185440-mutt-send-email-mst@redhat.com> From: Paolo Bonzini Message-ID: <56EAAD92.10007@redhat.com> Date: Thu, 17 Mar 2016 14:13:54 +0100 MIME-Version: 1.0 In-Reply-To: <20160316185440-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] firmware: qemu_fw_cfg.c: hold ACPI global lock during device access List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , Gabriel Somlo Cc: mark.rutland@arm.com, peter.maydell@linaro.org, matt@codeblueprint.co.uk, stefanha@gmail.com, qemu-devel@nongnu.org, eric@anholt.net, kraxel@redhat.com, linux-api@vger.kernel.org, agross@codeaurora.org, pawel.moll@arm.com, zajec5@gmail.com, rmk+kernel@arm.linux.org.uk, lersek@redhat.com, devicetree@vger.kernel.org, ehabkost@redhat.com, arnd@arndb.de, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, leif.lindholm@linaro.org, robh+dt@kernel.org, rth@twiddle.net, ard.biesheuvel@linaro.org, Greg KH , linux-kernel@vger.kernel.org, luto@amacapital.net, hanjun.guo@linaro.org, sudeep.holla@arm.com, imammedo@redhat.com, revol@free.fr On 16/03/2016 17:57, Michael S. Tsirkin wrote: > On Tue, Mar 08, 2016 at 01:30:50PM -0500, Gabriel Somlo wrote: >> Allowing for the future possibility of implementing AML-based >> (i.e., firmware-triggered) access to the QEMU fw_cfg device, >> acquire the global ACPI lock when accessing the device on behalf >> of the guest-side sysfs driver, to prevent any potential race >> conditions. >> >> Suggested-by: Michael S. Tsirkin >> Signed-off-by: Gabriel Somlo > > So this patch makes sense of course. > > > Given the recent discussion on QEMU mailing list, > I think there is an additional patch that we need: > filter the files exposed to userspace by "opt/" prefix. > > This will ensure that we can change all other fw cfg files > at will without breaking guest scripts. That makes no sense, all other fw_cfg files are firmware ABI so we cannot change them anyway. Paolo