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From: "Tian, Kevin" <kevin.tian@intel.com>
To: "Xuquan (Quan Xu)" <xuquan8@huawei.com>, Jan Beulich <JBeulich@suse.com>
Cc: "yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
	"Hanweidong (Randy)" <hanweidong@huawei.com>,
	"George.Dunlap@eu.citrix.com" <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Tim Deegan <tim@xen.org>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Jiangyifei <jiangyifei@huawei.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>
Subject: Re: [PATCH v2] x86/apicv: fix RTC periodic timer and apicv issue
Date: Mon, 24 Oct 2016 07:02:18 +0000	[thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D18DFDA5DB@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <E0A769A898ADB6449596C41F51EF62C6ABB33E@SZXEMI506-MBX.china.huawei.com>

> From: Xuquan (Quan Xu) [mailto:xuquan8@huawei.com]
> Sent: Monday, October 17, 2016 5:28 PM
> 
> >>
> >>Back to the main open before holiday - multiple EOIs may come to clear
> >>irq_issued before guest actually handles the very vpt injection
> >>(possible if vpt vector is shared with other sources). I don't see a
> >>good solution on that open... :/
> >>
> >>We've discussed various options which all fail in one or another place
> >>- either miss an injection, or incur undesired injections.
> >>Possibly we should consider another direction - fall back to non-apicv
> >>path when we see vpt vector pending but it's not the highest one.
> >>
> >>Original condition to enter virtual intr delivery:
> >>	    else if ( cpu_has_vmx_virtual_intr_delivery &&
> >>              intack.source != hvm_intsrc_pic &&
> >>              intack.source != hvm_intsrc_vector )
> >>
> >>now new condition:
> >>	    else if ( cpu_has_vmx_virtual_intr_delivery &&
> >>              intack.source != hvm_intsrc_pic &&
> >>              intack.source != hvm_intsrc_vector &&
> >>			(pt_vector == -1 || intack.vector == pt_vector) )
> >>
> >>Thoughts?
> >>
> >Kevin,
> >When I try to fix it as your suggestion, I cannot boot the guest, with below
> >message(from xl dmesg):
> 
> with Kevin's patch, the hypervisor always calls ' vmx_inject_extint() ->
> __vmx_inject_exception()' to inject exception, then vm-entry on loop..
> the interrupt (PT or IPI, or others) can't deliver to guest..
> 
> and so far, we suppress MSR-based APIC suggestion when having APIC-V by
> http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=7f2e992b824ec62a2818e643
> 90ac2ccfbd74e6b7
> so I think we couldn't fallback to non-apicv dynamically here..
> 

What about setting EOI exit bitmap for intack.vector when it's higher
than pending pt_vector? This way we can guarantee there's always a
chance to post pt_vector when pt_vector becomes the highest one...

(of course you need make later pt_intr_post conditionally then, only
when intack.vector==pt_vector)

Thanks
Kevin

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  parent reply	other threads:[~2016-10-24  7:02 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-20 13:30 [PATCH v2] x86/apicv: fix RTC periodic timer and apicv issue Xuquan (Euler)
2016-09-23 15:33 ` Jan Beulich
2016-09-23 23:34   ` Tian, Kevin
2016-09-24  1:06     ` Xuquan (Euler)
2016-09-26  6:39       ` Jan Beulich
2016-10-10  9:21         ` Xuquan (Quan Xu)
2016-10-10  9:39           ` Jan Beulich
2016-10-10 10:49             ` Xuquan (Quan Xu)
2016-10-11  7:48               ` Tian, Kevin
2016-10-11 11:12                 ` Xuquan (Quan Xu)
2016-10-17  9:27                 ` Xuquan (Quan Xu)
2016-10-21  8:43                   ` Tian, Kevin
2016-10-24  7:02                   ` Tian, Kevin [this message]
2016-10-25  8:36                     ` Xuquan (Quan Xu)
2016-10-25 13:01                       ` Konrad Rzeszutek Wilk
2016-10-26  8:42                         ` Xuquan (Quan Xu)
2016-10-26  5:19                       ` Tian, Kevin
2016-10-26  8:38                         ` Xuquan (Quan Xu)
2016-10-26  9:35                           ` Tian, Kevin
2016-10-26 12:02                             ` Xuquan (Quan Xu)
2016-10-25  9:01                     ` Xuquan (Quan Xu)
2016-09-26  6:35     ` Jan Beulich
2016-09-26 19:34       ` Tian, Kevin

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