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From: Dario Faggioli <dario.faggioli@citrix.com>
To: "Wu, Feng" <feng.wu@intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	"keir@xen.org" <keir@xen.org>,
	"george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	"jbeulich@suse.com" <jbeulich@suse.com>,
	"Zhang, Yang Z" <yang.z.zhang@intel.com>
Subject: Re: [v3 12/15] vmx: posted-interrupt handling when vCPU is blocked
Date: Thu, 2 Jul 2015 12:09:52 +0200	[thread overview]
Message-ID: <1435831792.25170.440.camel@citrix.com> (raw)
In-Reply-To: <E959C4978C3B6342920538CF579893F0025E4507@SHSMSX104.ccr.corp.intel.com>


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On Thu, 2015-07-02 at 08:58 +0000, Wu, Feng wrote:

> > -----Original Message-----
> > From: Dario Faggioli [mailto:dario.faggioli@citrix.com]
> >
> > This is the third time that I ask:
> >  (1) whether it is possible to have more vcpus queued on one pcpu PI
> >      blocked list with desc.on (I really believe it is);
> 
> I think it is, please see the following scenario:
> 
> When cpu masks the interrupts, and an external interrupt occurs for the
> assigned device while the target vCPU2 is blocked, the wakeup notification
> event handler has no chance to run, after a while, another wakeup
> notification event for vCPU4 blocking on the same pCPU occurs,
> after cpu unmakes the interrupts, wakeup notification handler
> gets called. Then we get:
> 	vCPU2, desc.on = 1 and vCPU4, desc.on = 1
> Then in the handler we need to kick both of them.
> 
Ok, first of all, thanks for answering! :-)

And yes, this makes sense.

> >  (2) if yes, whether it is TheRightThing(TM) to kick all of them, as
> >      soon as any notification arrives, instead that putting together a
> >      mechanism for kicking only a specific one.
> > 
> Why can't we kick all of them, 'desc.on = 1' means there is a pending
> interrupt, when we meet this condition, kicking the related vCPU should
> be the right thing to do.
> 
Right, I see it now. I felt like I was missing something, and that's why
I was asking to you to elaborate a bit more.
Thanks again for having done this. I was missing/forgetting half of the
way desc.on is actually handled, sorry for this.

BTW, I'm finding it hard reading this series from the archives; there
appears to be some threading issues and some missing messages. I also
don't have it in my inbox, because my filters failed to spot and flag it
properly. If you send a new version, please, Cc me, so it will be easier
for me to look at all the patches, and provide a more helpful review.

Thanks and Regards,
Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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  reply	other threads:[~2015-07-02 10:09 UTC|newest]

Thread overview: 155+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-24  5:18 [v3 00/15] Add VT-d Posted-Interrupts support Feng Wu
2015-06-24  5:18 ` [v3 01/15] Vt-d Posted-intterrupt (PI) design Feng Wu
2015-06-24  6:15   ` Meng Xu
2015-06-24  6:19     ` Wu, Feng
2015-07-08  7:21   ` Tian, Kevin
2015-07-08  7:29     ` Wu, Feng
2015-06-24  5:18 ` [v3 02/15] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-06-24 17:31   ` Andrew Cooper
2015-07-08  7:23   ` Tian, Kevin
2015-06-24  5:18 ` [v3 03/15] Add cmpxchg16b support for x86-64 Feng Wu
2015-06-24 18:35   ` Andrew Cooper
2015-07-08  7:06     ` Wu, Feng
2015-07-08  8:12       ` Jan Beulich
2015-07-08  8:33         ` Wu, Feng
2015-07-08  8:43           ` Jan Beulich
2015-07-08  8:50             ` Wu, Feng
2015-07-08  8:50         ` Andrew Cooper
2015-07-10 12:57   ` Jan Beulich
2015-06-24  5:18 ` [v3 04/15] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-06-25  9:06   ` Andrew Cooper
2015-06-25  9:47     ` Wu, Feng
2015-06-25 10:16       ` Andrew Cooper
2015-06-25 12:47         ` Wu, Feng
2015-07-08  7:30   ` Tian, Kevin
2015-06-24  5:18 ` [v3 05/15] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-06-25 10:21   ` Andrew Cooper
2015-06-25 13:02     ` Wu, Feng
2015-07-08  7:32   ` Tian, Kevin
2015-07-08  8:00     ` Wu, Feng
2015-06-24  5:18 ` [v3 06/15] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-06-29 15:04   ` Andrew Cooper
2015-07-08  7:48   ` Tian, Kevin
2015-07-10 13:08   ` Jan Beulich
2015-07-15  2:40     ` Wu, Feng
2015-07-15  8:20       ` Jan Beulich
2015-07-15  8:26         ` Wu, Feng
2015-07-15  8:36           ` Jan Beulich
2015-07-15  8:43             ` Wu, Feng
2015-07-15  9:28               ` Jan Beulich
2015-07-15  9:30                 ` Wu, Feng
2015-07-15  3:13     ` Wu, Feng
2015-06-24  5:18 ` [v3 07/15] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-06-29 15:32   ` Andrew Cooper
2015-06-30  1:46     ` Wu, Feng
2015-06-30  2:32     ` Dario Faggioli
2015-07-08  7:53   ` Tian, Kevin
2015-06-24  5:18 ` [v3 08/15] Suppress posting interrupts when 'SN' is set Feng Wu
2015-06-29 15:41   ` Andrew Cooper
2015-06-30  1:48     ` Wu, Feng
2015-07-08  9:06   ` Tian, Kevin
2015-07-08 10:11     ` Wu, Feng
2015-07-08 11:31       ` Tian, Kevin
2015-07-08 11:58         ` Wu, Feng
2015-07-10 13:20   ` Jan Beulich
2015-06-24  5:18 ` [v3 09/15] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-06-29 16:04   ` Andrew Cooper
2015-06-30  1:52     ` Wu, Feng
2015-07-08  9:10   ` Tian, Kevin
2015-07-10 13:27   ` Jan Beulich
2015-06-24  5:18 ` [v3 10/15] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-06-29 16:22   ` Andrew Cooper
2015-07-08  9:59   ` Tian, Kevin
2015-07-08 10:12     ` Wu, Feng
2015-07-10 14:01   ` Jan Beulich
2015-07-15  6:04     ` Wu, Feng
2015-07-15  8:24       ` Jan Beulich
2015-07-15  8:38         ` Wu, Feng
2015-07-15  8:46           ` Jan Beulich
2015-07-15  8:55             ` Wu, Feng
2015-07-15  9:32               ` Jan Beulich
2015-06-24  5:18 ` [v3 11/15] Update IRTE according to guest interrupt config changes Feng Wu
2015-06-29 16:46   ` Andrew Cooper
2015-07-08 10:22   ` Tian, Kevin
2015-07-08 10:31     ` Wu, Feng
2015-07-08 11:46       ` Tian, Kevin
2015-07-08 11:52         ` Wu, Feng
2015-07-08 11:54           ` Tian, Kevin
2015-07-10 14:23   ` Jan Beulich
2015-06-24  5:18 ` [v3 12/15] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-06-29 17:07   ` Andrew Cooper
2015-07-08 10:36     ` Wu, Feng
2015-07-08 10:48       ` Jan Beulich
     [not found]   ` <559181F9.6020106@citrix.com>
2015-06-30  2:51     ` Fwd: " Dario Faggioli
2015-06-30  2:59       ` Wu, Feng
2015-06-30  9:46         ` Dario Faggioli
2015-06-30 10:11   ` Andrew Cooper
2015-07-01 13:26     ` Dario Faggioli
2015-07-02  4:27       ` Wu, Feng
2015-07-02  8:30         ` Dario Faggioli
2015-07-02  8:58           ` Wu, Feng
2015-07-02 10:09             ` Dario Faggioli [this message]
2015-07-02 10:41               ` Wu, Feng
2015-07-02 10:30           ` Andrew Cooper
2015-07-02 10:56             ` Wu, Feng
2015-07-02 12:04             ` Dario Faggioli
2015-07-02 12:10               ` Wu, Feng
2015-07-02 12:16               ` Andrew Cooper
2015-07-02 12:38                 ` Dario Faggioli
2015-07-02 12:59                   ` Andrew Cooper
2015-07-03  1:33                     ` Wu, Feng
2015-07-02  4:25     ` Wu, Feng
2015-07-08 11:00   ` Tian, Kevin
2015-07-08 11:02     ` Wu, Feng
2015-07-08 12:46     ` Jan Beulich
2015-07-08 13:09       ` Andrew Cooper
2015-07-08 22:49         ` Tian, Kevin
2015-07-09  7:25           ` Jan Beulich
2015-07-10  6:21             ` Wu, Feng
2015-07-10  6:32               ` Jan Beulich
2015-07-10  7:29                 ` Wu, Feng
2015-07-10  8:49                   ` Jan Beulich
2015-07-10  8:57                     ` Wu, Feng
2015-07-08 22:31       ` Tian, Kevin
2015-06-24  5:18 ` [v3 13/15] vmx: Properly handle notification event when vCPU is running Feng Wu
2015-07-08 11:03   ` Tian, Kevin
2015-07-10 14:40   ` Jan Beulich
2015-06-24  5:18 ` [v3 14/15] Update Posted-Interrupts Descriptor during vCPU scheduling Feng Wu
     [not found]   ` <55918214.4030102@citrix.com>
2015-06-30  2:58     ` Fwd: " Dario Faggioli
2015-07-02  4:32       ` Wu, Feng
2015-07-02  4:34         ` Wu, Feng
2015-07-02  8:20         ` Dario Faggioli
2015-07-09  3:09           ` Wu, Feng
2015-07-09  8:18             ` Dario Faggioli
2015-07-09 11:19             ` George Dunlap
2015-07-09 11:29               ` George Dunlap
2015-07-09 11:38               ` Wu, Feng
2015-07-09 12:42                 ` Dario Faggioli
2015-07-10  0:07                   ` Wu, Feng
2015-07-10 12:40                     ` Dario Faggioli
2015-07-10 13:47                       ` Konrad Rzeszutek Wilk
2015-07-10 13:59                         ` Dario Faggioli
2015-07-09 12:53                 ` George Dunlap
2015-07-09 13:44                   ` Jan Beulich
2015-07-09 14:18                     ` Dario Faggioli
2015-07-09 14:27                       ` George Dunlap
2015-07-09 14:47                         ` Dario Faggioli
2015-07-10  5:59                         ` Wu, Feng
2015-07-10  6:22                           ` Jan Beulich
2015-07-10 11:05                             ` Dario Faggioli
2015-07-14  5:44                               ` Wu, Feng
2015-07-14 14:08                               ` Wu, Feng
2015-07-14 14:54                                 ` Jan Beulich
2015-07-14 15:20                                   ` Dario Faggioli
2015-07-14 16:41                                     ` George Dunlap
2015-07-14 16:02                                 ` Dario Faggioli
2015-07-15  0:54                                   ` Wu, Feng
2015-07-17  7:46                                   ` Wu, Feng
2015-07-17 10:13                                     ` Dario Faggioli
2015-07-17 22:57                                       ` Wu, Feng
2015-07-18 13:43                                         ` Dario Faggioli
2015-07-10  0:15                   ` Wu, Feng
2015-07-08 11:24   ` Tian, Kevin
2015-07-10 14:48   ` Jan Beulich
2015-06-24  5:18 ` [v3 15/15] Add a command line parameter for VT-d posted-interrupts Feng Wu
2015-07-08 11:25   ` Tian, Kevin

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