Re: [Xen-devel] [PATCH v2 08/16] xen/hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<ard.biesheuvel@linaro.org>, <stefano.stabellini@citrix.com>,
	<david.vrabel@citrix.com>, <mark.rutland@arm.com>,
	<devicetree@vger.kernel.org>, <linux-efi@vger.kernel.org>,
	<catalin.marinas@arm.com>, <will.deacon@arm.com>,
	<linux-kernel@vger.kernel.org>, <xen-devel@lists.xen.org>,
	<julien.grall@citrix.com>, <shannon.zhao@linaro.org>,
	<peter.huangpeng@huawei.com>, <zhaoshenglong@huawei.com>
Subject: Re: [Xen-devel] [PATCH v2 08/16] xen/hvm/params: Add a new delivery type for event-channel in HVM_PARAM_CALLBACK_IRQ
Date: Mon, 18 Jan 2016 12:46:43 +0000	[thread overview]
Message-ID: <alpine.DEB.2.02.1601181244300.16178@kaball.uk.xensource.com> (raw)
In-Reply-To: <569CDDB7.9030103@citrix.com>

On Mon, 18 Jan 2016, Andrew Cooper wrote:
> On 18/01/16 12:38, Stefano Stabellini wrote:
> > On Fri, 15 Jan 2016, Shannon Zhao wrote:
> >> From: Shannon Zhao <shannon.zhao@linaro.org>
> >>
> >> Add a new delivery type:
> >> val[63:56] == 3: val[15:8] is flag: val[7:0] is a PPI.
> >> To the flag, bit 0 stands the interrupt mode is edge(1) or level(0) and
> >> bit 1 stands the interrupt polarity is active low(1) or high(0).
> >>
> >> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> >> ---
> >>  include/xen/interface/hvm/params.h | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >> diff --git a/include/xen/interface/hvm/params.h b/include/xen/interface/hvm/params.h
> >> index a6c7991..550688a 100644
> >> --- a/include/xen/interface/hvm/params.h
> >> +++ b/include/xen/interface/hvm/params.h
> >> @@ -34,6 +34,11 @@
> >>   *                  Domain = val[47:32], Bus  = val[31:16],
> >>   *                  DevFn  = val[15: 8], IntX = val[ 1: 0]
> >>   * val[63:56] == 2: val[7:0] is a vector number.
> >> + * val[63:56] == 3: val[15:8] is flag of event-channel interrupt:
> >> + *                      bit 0: interrupt is edge(1) or level(0) triggered
> >> + *                      bit 1: interrupt is active low(1) or high(0)
> >> + *                  val[7:0] is PPI number used by event-channel.
> >> + *                  This is only used by ARM/ARM64.
> >>   * If val == 0 then CPU0 event-channel notifications are not delivered.
> >>   */
> >>  #define HVM_PARAM_CALLBACK_IRQ 0
> > Andrew, I think that this patch is correct. Looking back at your
> > previous comment (http://marc.info/?l=devicetree&m=144804014214262&w=2),
> > is it possible that you were confused by enum callback_via_type, which
> > is internal to Xen and offset'ed by 1 compared to the described values
> > in xen/include/public/hvm/params.h?
> >
> > If not, and indeed somebody introduced one more field but failed to
> > document it, then I suggest she sends a patch to fix the issue as soon
> > as possible.
> 
> I was indeed confused - the ABI is utterly mad.

All right. In that case, Shannon, you can add my

Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

> However, this change does need rebasing over c/s ca5c54b, which was the
> result of the original discussion.

c/s ca5c54b is for Xen, while this is a Linux patch (Linux has its own
set of Xen headers).