From: Gleb Natapov <gleb@redhat.com>
To: "Zhang, Yang Z" <yang.z.zhang@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Zhang, Xiantao" <xiantao.zhang@intel.com>
Subject: Re: [PATCH v6 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt
Date: Wed, 20 Mar 2013 13:49:13 +0200 [thread overview]
Message-ID: <20130320114913.GJ3889@redhat.com> (raw)
In-Reply-To: <A9667DDFB95DB7438FA9D7D576C3D87E099E8B36@SHSMSX101.ccr.corp.intel.com>
On Wed, Mar 20, 2013 at 11:47:49AM +0000, Zhang, Yang Z wrote:
> Gleb Natapov wrote on 2013-03-20:
> > On Tue, Mar 19, 2013 at 12:27:38PM -0300, Marcelo Tosatti wrote:
> >> On Tue, Mar 19, 2013 at 12:19:55PM -0300, Marcelo Tosatti wrote:
> >>> See the previous argument: should never enter guest mode with PIR ON bit
> >>> set. With logic above:
> >>>
> >>> context1 context2 context3
> >>> set_bit(PIR-1)
> >>> r = pi_test_and_set_on() set_bit(PIR-40)
> >>> set_bit(KVM_REQ_EVENT)
> >>> if (kvm_check_request(KVM_REQ_EVENT)
> >>> if (test_and_clear_bit(on))
> >>> kvm_apic_update_irr() r =
> > pi_test_and_set_on()
> >>>
> >>> guest entry with PIR ON=1
> >>>
> >>>
> >>> Thats the reason for unconditional clearing on guest entry: it is easy
> >>> to verify its correct. I understand and agree the callback (and VMWRITE)
> >>> is not nice.
> >>
> >> Re: KVM_REQ_EVENT setting after set_bit(KVM_REQ_EVENT) assures no guest
> >> entry with PIR ON=1.
> >>
> >> Might be, would have to verify. Its trickier though. Maybe add a FIXME:
> >> to the callback and remove it later.
> > We have time still. RTC series is not ready yet. I'll think hard and try
> > to poke holes in the logic in this patch and you do the same for what I
> > propose.
> Any thought? As far as I see, the two solutions are ok. It's hard to say which is better. But clear ON bit when sync_pir_irr should be more clear and close to hardware's behavior.
>
Lets go with it unless we see why it will not work.
--
Gleb.
next prev parent reply other threads:[~2013-03-20 11:49 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-15 13:31 [PATCH v6 0/5] KVM: VMX: Add Posted Interrupt supporting Yang Zhang
2013-03-15 13:31 ` [PATCH v6 1/5] KVM: VMX: Enable acknowledge interupt on vmexit Yang Zhang
2013-03-15 13:31 ` [PATCH v6 2/5] KVM: VMX: Register a new IPI for posted interrupt Yang Zhang
2013-03-15 13:31 ` [PATCH v6 3/5] KVM: VMX: Check the posted interrupt capability Yang Zhang
2013-03-15 13:31 ` [PATCH v6 4/5] KVM: VMX: Add the algorithm of deliver posted interrupt Yang Zhang
2013-03-15 13:31 ` [PATCH v6 5/5] KVM : VMX: Use posted interrupt to deliver virtual interrupt Yang Zhang
2013-03-19 8:54 ` Gleb Natapov
2013-03-19 12:11 ` Zhang, Yang Z
2013-03-19 12:23 ` Gleb Natapov
2013-03-19 12:42 ` Zhang, Yang Z
2013-03-19 13:29 ` Gleb Natapov
2013-03-19 13:59 ` Zhang, Yang Z
2013-03-19 14:51 ` Gleb Natapov
2013-03-19 15:12 ` Gleb Natapov
2013-03-19 15:19 ` Marcelo Tosatti
2013-03-19 15:27 ` Marcelo Tosatti
2013-03-19 16:10 ` Gleb Natapov
2013-03-20 11:47 ` Zhang, Yang Z
2013-03-20 11:49 ` Gleb Natapov [this message]
2013-03-20 11:52 ` Zhang, Yang Z
2013-03-19 15:30 ` Gleb Natapov
2013-03-19 15:13 ` Marcelo Tosatti
2013-03-19 15:21 ` Gleb Natapov
2013-03-19 15:03 ` Marcelo Tosatti
2013-03-19 15:18 ` Gleb Natapov
2013-03-18 2:49 ` [PATCH v6 0/5] KVM: VMX: Add Posted Interrupt supporting Zhang, Yang Z
2013-03-18 9:16 ` Gleb Natapov
2013-03-18 10:43 ` Zhang, Yang Z
2013-03-18 11:28 ` Gleb Natapov
2013-03-18 11:44 ` Zhang, Yang Z
2013-03-18 22:20 ` Marcelo Tosatti
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