From: "Xuquan (Quan Xu)" <xuquan8@huawei.com>
To: Jan Beulich <JBeulich@suse.com>, KevinTian <kevin.tian@intel.com>,
Chao Gao <chao.gao@intel.com>
Cc: "yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
"quan.xu0@gmail.com" <quan.xu0@gmail.com>,
Jun Nakajima <jun.nakajima@intel.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH] x86/apicv: enhance posted-interrupt processing
Date: Thu, 23 Feb 2017 11:55:15 +0000 [thread overview]
Message-ID: <E0A769A898ADB6449596C41F51EF62C6AE8236@SZXEMI506-MBX.china.huawei.com> (raw)
In-Reply-To: <58AECF09020000780013D29A@prv-mh.provo.novell.com>
On February 23, 2017 7:01 PM, Jan Beulich wrote:
>>>> On 23.02.17 at 11:53, <xuquan8@huawei.com> wrote:
>> On February 23, 2017 5:59 PM, Jan Beulich wrote:
>>>>>> On 23.02.17 at 10:28, <xuquan8@huawei.com> wrote:
>>>> On February 18, 2017 12:33 AM, Jan Beulich wrote:
>>>>>>>> On 17.02.17 at 09:49, <chao.gao@intel.com> wrote:
>>>>>>>diff --git a/xen/arch/x86/hvm/vmx/vmx.c
>>>b/xen/arch/x86/hvm/vmx/vmx.c
>>>>>>>index 61925cf..3887c32 100644
>>>>>>>--- a/xen/arch/x86/hvm/vmx/vmx.c
>>>>>>>+++ b/xen/arch/x86/hvm/vmx/vmx.c
>>>>>>>@@ -1846,8 +1846,7 @@ static void
>>>>>__vmx_deliver_posted_interrupt(struct vcpu *v)
>>>>>>> {
>>>>>>> unsigned int cpu = v->processor;
>>>>>>>
>>>>>>>- if ( !test_and_set_bit(VCPU_KICK_SOFTIRQ,
>>>>>&softirq_pending(cpu))
>>>>>>>- && (cpu != smp_processor_id()) )
>>>>>>>+ if ( !softirq_pending(cpu) && (cpu != smp_processor_id())
>>>>>>>+ )
>>>>
>>>> Jan,
>>>> could you help me present the definition of ' smp_processor_id()'
>and '
>>>> current' in __vmx_deliver_posted_interrupt() ? thanks..
>>>
>>>I'm afraid I don't understand the request.
>>
>> IOW,
>> which vcpu does the 'current' refer to?
>> which cpu does the ' smp_processor_id()' refer to?
>
>current: currently running vCPU
in a SMP machine, are there more than one currently running vCPU?
I think so, the condition "if ( running && (in_irq() || (v != current)) )", in __vmx_deliver_posted_interrupt() looks strange -- when vCPU is running, why to check ' v != current '..
>smp_processor_id(): processor ID of the CPU we're running on
>
I think if vcpu is running, ' cpu != smp_processor_id() ' should be true.
I think we could simplify __vmx_deliver_posted_interrupt():
1. set VCPU_KICK_SOFTIRQ bit of v->processor.
2. IF vcpu is running:
- send_IPI
ELSE
- vcpu_kick
Thank you for your patience..
Quan
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next prev parent reply other threads:[~2017-02-23 11:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-17 9:37 [PATCH] x86/apicv: enhance posted-interrupt processing Xuquan (Quan Xu)
2017-02-17 8:49 ` Chao Gao
2017-02-17 16:32 ` Jan Beulich
2017-02-20 11:25 ` Xuquan (Quan Xu)
2017-02-20 8:24 ` Chao Gao
2017-02-21 2:49 ` Xuquan (Quan Xu)
2017-02-21 3:07 ` Tian, Kevin
2017-02-21 4:11 ` Xuquan (Quan Xu)
2017-02-20 21:54 ` Chao Gao
2017-02-21 6:19 ` Xuquan (Quan Xu)
2017-02-21 9:08 ` Jan Beulich
2017-02-21 9:44 ` Tian, Kevin
2017-02-23 9:28 ` Xuquan (Quan Xu)
2017-02-23 9:59 ` Jan Beulich
2017-02-23 10:53 ` Xuquan (Quan Xu)
2017-02-23 11:01 ` Jan Beulich
2017-02-23 11:55 ` Xuquan (Quan Xu) [this message]
2017-02-23 8:37 ` Chao Gao
2017-02-27 8:00 ` Xuquan (Quan Xu)
2017-02-23 12:26 ` Jan Beulich
2017-02-24 8:02 ` Xuquan (Quan Xu)
2017-02-24 8:20 ` Jan Beulich
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