From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <roger.pau@citrix.com>
Subject: Re: [PATCH v7 23/32] xen/x86: make sure the HVM
 callback vector is correctly set
Date: Fri, 30 Oct 2015 16:34:50 +0100
Message-ID: <56338E1A.7070100@citrix.com>
References: <1443800943-17668-1-git-send-email-roger.pau@citrix.com>
	<1443800943-17668-24-git-send-email-roger.pau@citrix.com>
	<561E96C402000078000AB0CF@prv-mh.provo.novell.com>
	<561E7C5C.1060406@citrix.com>
	<9AAE0902D5BC7E449B7C8E4E778ABCD02F613C61@AMSPEX01CL01.citrite.net>
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=738e045eb=roger.pau@citrix.com>)
	id 1ZsBi8-00021o-9l
	for xen-devel@lists.xenproject.org; Fri, 30 Oct 2015 15:35:24 +0000
In-Reply-To: <9AAE0902D5BC7E449B7C8E4E778ABCD02F613C61@AMSPEX01CL01.citrite.net>
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>, Andrew Cooper <Andrew.Cooper3@citrix.com>, Jan Beulich <JBeulich@suse.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
List-Id: xen-devel@lists.xenproject.org

El 15/10/15 a les 13.30, Paul Durrant ha escrit:
>> -----Original Message-----
>> From: xen-devel-bounces@lists.xen.org [mailto:xen-devel-
>> bounces@lists.xen.org] On Behalf Of Andrew Cooper
>> Sent: 14 October 2015 17:02
>> To: Jan Beulich; Roger Pau Monne
>> Cc: xen-devel@lists.xenproject.org
>> Subject: Re: [Xen-devel] [PATCH v7 23/32] xen/x86: make sure the HVM
>> callback vector is correctly set
>>
>> On 14/10/15 16:54, Jan Beulich wrote:
>>>>>> On 02.10.15 at 17:48, <roger.pau@citrix.com> wrote:
>>>> --- a/xen/arch/x86/hvm/irq.c
>>>> +++ b/xen/arch/x86/hvm/irq.c
>>>> @@ -330,6 +330,10 @@ void hvm_set_callback_via(struct domain *d,
>> uint64_t
>>>> via)
>>>>           (via_type > HVMIRQ_callback_vector) )
>>>>          via_type = HVMIRQ_callback_none;
>>>>
>>>> +    if ( via_type != HVMIRQ_callback_vector &&
>>>> +         (!has_vlapic(d) || !has_vioapic(d) || !has_vpic(d)) )
>>>> +        return;
>>> Why are both IO-APIC and PIC required? Doesn't one suffice, or
>>> can't MSI-like interrupts even get delivered without either?
>>
>> In real hardware, MSI-like interrupts have no interaction with the
>> IO-APIC or PIC.
>>
>> In fact, the purpose of the IO-APIC is to turn legacy line interrupts
>> into MSI interrupts.  The PICs were from the pre-MSI days where it
>> asserted the #INTR pin on the processor.
>>
>> Our virtual interrupt infrastructure should behave in a consistent manor.
>>
> 
> IIRC both the intx and gsi variants of the callback via go in at the vioapic level.

OK, so I can remove the PIC requirement.

Roger.