From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Tian, Kevin" <kevin.tian@intel.com>
Subject: Re: [PATCH v9 08/17] vmx: Suppress posting interrupts
 when 'SN' is set
Date: Tue, 24 Nov 2015 07:29:47 +0000
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To: "Wu, Feng" <feng.wu@intel.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Keir Fraser <keir@xen.org>, Jan Beulich <jbeulich@suse.com>
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> From: Wu, Feng
> Sent: Tuesday, November 03, 2015 4:43 PM
N' is set
> 
> Currently, we don't support urgent interrupt, all interrupts
> are recognized as non-urgent interrupt, so we cannot send
> posted-interrupt when 'SN' is set.
> 
> CC: Kevin Tian <kevin.tian@intel.com>
> CC: Keir Fraser <keir@xen.org>
> CC: Jan Beulich <jbeulich@suse.com>
> CC: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Feng Wu <feng.wu@intel.com>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Kevin Tian <kevin.tian@intel.com>, with one small comment:

> +        do {
> +            /*
> +             * Currently, we don't support urgent interrupt, all
> +             * interrupts are recognized as non-urgent interrupt,
> +             * so we cannot send posted-interrupt when 'SN' is set.
> +             * Besides that, if 'ON' is already set, we cannot set
> +             * posted-interrupts as well.
> +             */

Is above comment accurate. "cannot set" is too strong for 'ON'
already set, right? Ideally there's no correctness issue if you
still deliver another posted-interrupt even when ON is already set.
To me it's more like an optimization then it's cleaner to say 
"we can avoid"...

Thanks
Kevin