Re: [Xen-devel] [PATCH] x86/apicv: enhance posted-interrupt processing

["Xuquan (Quan Xu)" <xuquan8@xxxxxxxxxx>]

On February 23, 2017 5:59 PM, Jan Beulich wrote:
>>>> On 23.02.17 at 10:28, <xuquan8@xxxxxxxxxx> wrote:
>> On February 18, 2017 12:33 AM, Jan Beulich wrote:
>>>>>> On 17.02.17 at 09:49, <chao.gao@xxxxxxxxx> wrote:
>>>> On Fri, Feb 17, 2017 at 09:37:45AM +0000, Xuquan (Quan Xu) wrote:
>>>>>From a589074281cc22a30ed75a5bccba60e83d2312a6 Mon Sep 17
>>>00:00:00 2001
>>>>>From: Quan Xu <xuquan8@xxxxxxxxxx>
>>>>>Date: Sat, 18 Feb 2017 09:27:37 +0800
>>>>>Subject: [PATCH] x86/apicv: enhance posted-interrupt processing
>>>>>
>>>>>If guest is already in non-root mode, an posted interrupt will be
>>>>>directly delivered to guest (leaving softirq being set w/o actually
>>>>>incurring a VM-Exit - breaking desired softirq behavior).
>>>>>Then further posted interrupts will skip the IPI, stay in PIR and
>>>>>not noted until another VM-Exit happens.
>>>>>
>>>>>Remove the softirq set. Actually since it's an optimization for less
>>>>>IPIs, check softirq_pending(cpu) directly instead of sticking to one
>>>>>bit only.
>>>>>
>>>>>Signed-off-by: Quan Xu <xuquan8@xxxxxxxxxx>
>>>>>---
>>>>> xen/arch/x86/hvm/vmx/vmx.c | 3 +--
>>>>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>>>>
>>>>>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?




Quan

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