From 91e0c5f3dad47838cb2ecc1865ce789a0b7182b1 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 16 Oct 2007 11:51:30 -0700 Subject: xen: add batch completion callbacks This adds a mechanism to register a callback function to be called once a batch of hypercalls has been issued. This is typically used to unlock things which must remain locked until the hypercall has taken place. [ Stable folks: pre-req for 2.6.23 bugfix "xen: deal with stale cr3 values when unpinning pagetables" ] Signed-off-by: Jeremy Fitzhardinge Cc: Stable Kernel --- arch/x86/xen/multicalls.c | 29 ++++++++++++++++++++++++++--- arch/x86/xen/multicalls.h | 3 +++ 2 files changed, 29 insertions(+), 3 deletions(-) (limited to 'arch/x86/xen') diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c index c837e8e463d..ce9c4b41f02 100644 --- a/arch/x86/xen/multicalls.c +++ b/arch/x86/xen/multicalls.c @@ -32,7 +32,11 @@ struct mc_buffer { struct multicall_entry entries[MC_BATCH]; u64 args[MC_ARGS]; - unsigned mcidx, argidx; + struct callback { + void (*fn)(void *); + void *data; + } callbacks[MC_BATCH]; + unsigned mcidx, argidx, cbidx; }; static DEFINE_PER_CPU(struct mc_buffer, mc_buffer); @@ -43,6 +47,7 @@ void xen_mc_flush(void) struct mc_buffer *b = &__get_cpu_var(mc_buffer); int ret = 0; unsigned long flags; + int i; BUG_ON(preemptible()); @@ -51,8 +56,6 @@ void xen_mc_flush(void) local_irq_save(flags); if (b->mcidx) { - int i; - if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0) BUG(); for (i = 0; i < b->mcidx; i++) @@ -65,6 +68,13 @@ void xen_mc_flush(void) local_irq_restore(flags); + for(i = 0; i < b->cbidx; i++) { + struct callback *cb = &b->callbacks[i]; + + (*cb->fn)(cb->data); + } + b->cbidx = 0; + BUG_ON(ret); } @@ -88,3 +98,16 @@ struct multicall_space __xen_mc_entry(size_t args) return ret; } + +void xen_mc_callback(void (*fn)(void *), void *data) +{ + struct mc_buffer *b = &__get_cpu_var(mc_buffer); + struct callback *cb; + + if (b->cbidx == MC_BATCH) + xen_mc_flush(); + + cb = &b->callbacks[b->cbidx++]; + cb->fn = fn; + cb->data = data; +} diff --git a/arch/x86/xen/multicalls.h b/arch/x86/xen/multicalls.h index 5d96a5fa210..8bae996d99a 100644 --- a/arch/x86/xen/multicalls.h +++ b/arch/x86/xen/multicalls.h @@ -42,4 +42,7 @@ static inline void xen_mc_issue(unsigned mode) local_irq_restore(x86_read_percpu(xen_mc_irq_flags)); } +/* Set up a callback to be called when the current batch is flushed */ +void xen_mc_callback(void (*fn)(void *), void *data); + #endif /* _XEN_MULTICALLS_H */ -- cgit v1.2.3