From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Wu, Feng" Subject: Re: [PATCH v9 08/17] vmx: Suppress posting interrupts when 'SN' is set Date: Tue, 24 Nov 2015 07:55:13 +0000 Message-ID: References: <1446540207-4806-1-git-send-email-feng.wu@intel.com> <1446540207-4806-9-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Tian, Kevin" , "xen-devel@lists.xen.org" Cc: Andrew Cooper , "Wu, Feng" , Keir Fraser , Jan Beulich List-Id: xen-devel@lists.xenproject.org > -----Original Message----- > From: Tian, Kevin > Sent: Tuesday, November 24, 2015 3:53 PM > To: Wu, Feng ; xen-devel@lists.xen.org > Cc: Keir Fraser ; Jan Beulich ; Andrew > Cooper > Subject: RE: [PATCH v9 08/17] vmx: Suppress posting interrupts when 'SN' is > set > > > From: Wu, Feng > > Sent: Tuesday, November 24, 2015 3:47 PM > > > > > > > -----Original Message----- > > > From: Tian, Kevin > > > Sent: Tuesday, November 24, 2015 3:30 PM > > > To: Wu, Feng ; xen-devel@lists.xen.org > > > Cc: Keir Fraser ; Jan Beulich ; > Andrew > > > Cooper > > > Subject: RE: [PATCH v9 08/17] vmx: Suppress posting interrupts when 'SN' > is > > > set > > > > > > > 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 > > > > CC: Keir Fraser > > > > CC: Jan Beulich > > > > CC: Andrew Cooper > > > > Signed-off-by: Feng Wu > > > > Reviewed-by: Konrad Rzeszutek Wilk > > > > Reviewed-by: Jan Beulich > > > > > > Acked-by: Kevin Tian , 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"... > > > > Here, we just emulate the hardware's behavior, in hardware p.o.v, > > if 'ON' is set, the notification event will not be delivered, so here > > I try to follow the hardware, is this reasonable for you? > > > > I understand it's hardware behavior, just thought whether the comment > is too strong. Could we rephrase it as "Besides that, if 'ON' is already > set, no need to set posted-interrupts as well, according to hardware > behavior"? Sure, that should be great! Thanks a lot:) Thanks, Feng > > Thanks > Kevin