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

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> 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.

Jan


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