[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] x86/apicv: enhance posted-interrupt processing
>>> 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()) ) > HI, Quan. > Is there a situation that we need set VCPU_KICK_SOFTIRQ. For example, > after vmx_intr_assist(), a interrupt happened and its handler called this > function to deliver interrupt to current vcpu. In that case, the interrupt > would not be injected to guest before this VM-entry for we don't generate a > softirq and don't send a self-IPI to current vcpu. Good point, I think we indeed want to retain the old behavior (but in a not open coded fashion) for the cpu == smp_processor_id() case. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |