From 3a3f4f00afcdcf2cdae47319168b8dadab41c4f4 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Fri, 4 Dec 2020 13:14:42 +0100 Subject: [PATCH] viridian: use softirq batching in hvcall_ipi() vlapic_ipi() uses a softirq batching mechanism to improve the efficiency of sending a IPIs to large number of processors. This patch modifies send_ipi() (the worker function called by hvcall_ipi()) to also make use of the mechanism when there multiple bits set the hypercall_vpmask. Signed-off-by: Paul Durrant Reviewed-by: Jan Beulich Acked-by: Wei Liu --- xen/arch/x86/hvm/viridian/viridian.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/xen/arch/x86/hvm/viridian/viridian.c b/xen/arch/x86/hvm/viridian/viridian.c index 3e2393be41..894946abcb 100644 --- a/xen/arch/x86/hvm/viridian/viridian.c +++ b/xen/arch/x86/hvm/viridian/viridian.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -571,6 +572,11 @@ static unsigned int vpmask_next(const struct hypercall_vpmask *vpmask, (vp) < HVM_MAX_VCPUS; \ (vp) = vpmask_next(vpmask, vp) ) +static unsigned int vpmask_nr(const struct hypercall_vpmask *vpmask) +{ + return bitmap_weight(vpmask->mask, HVM_MAX_VCPUS); +} + /* * Windows should not issue the hypercalls requiring this callback in the * case where vcpu_id would exceed the size of the mask. @@ -654,10 +660,17 @@ static int hvcall_flush(const union hypercall_input *input, static void send_ipi(struct hypercall_vpmask *vpmask, uint8_t vector) { struct domain *currd = current->domain; + unsigned int nr = vpmask_nr(vpmask); unsigned int vp; + if ( nr > 1 ) + cpu_raise_softirq_batch_begin(); + for_each_vp ( vpmask, vp ) vlapic_set_irq(vcpu_vlapic(currd->vcpu[vp]), vector, 0); + + if ( nr > 1 ) + cpu_raise_softirq_batch_finish(); } static int hvcall_ipi(const union hypercall_input *input, -- 2.30.2