From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v5 12/16] x86/hvm: remove HVMIO_dispatched
	I/O state
Date: Fri, 3 Jul 2015 16:12:40 +0100
Message-ID: <5596A668.3040207@citrix.com>
References: <1435669558-5421-1-git-send-email-paul.durrant@citrix.com>
	<1435669558-5421-13-git-send-email-paul.durrant@citrix.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta3.messagelabs.com ([195.245.230.39])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <prvs=619030a5f=Andrew.Cooper3@citrix.com>)
	id 1ZB2e3-0006d5-3i
	for xen-devel@lists.xenproject.org; Fri, 03 Jul 2015 15:12:51 +0000
In-Reply-To: <1435669558-5421-13-git-send-email-paul.durrant@citrix.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Paul Durrant <paul.durrant@citrix.com>, xen-devel@lists.xenproject.org
Cc: Keir Fraser <keir@xen.org>, Jan Beulich <jbeulich@suse.com>
List-Id: xen-devel@lists.xenproject.org

On 30/06/15 14:05, Paul Durrant wrote:
> By removing the HVMIO_dispatched state and making all pending emulations
> (i.e. all those not handled by the hypervisor) use HVMIO_awating_completion,
> various code-paths can be simplified.
>
> The completion case for HVMIO_dispatched can also be trivally removed
> from hvmemul_do_io() as it was already unreachable. This is because that
> state was only ever used for writes or I/O to/from a guest page and
> hvmemul_do_io() is never called to complete such I/O.
>
> NOTE: There is one sublety in handle_pio()... The only case when
>       handle_pio() got a return code of X86EMUL_RETRY back from
>       hvmemul_do_pio_buffer() and found io_state was not
>       HVMIO_awaiting_completion was in the case where the domain is
>       shutting down. This is because all writes normally yield a return
>       of HVMEMUL_OKAY and all reads put io_state into
>       HVMIO_awaiting_completion. Hence the io_state check there is
>       replaced with a check of the is_shutting_down flag on the domain.
>
> Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
> Cc: Keir Fraser <keir@xen.org>
> Cc: Jan Beulich <jbeulich@suse.com>
> Cc: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>