diff options
author | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2012-08-22 16:20:11 (GMT) |
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committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-08-23 14:18:07 (GMT) |
commit | b5e579232d635b79a3da052964cb357ccda8d9ea (patch) | |
tree | b7920e93278da03f1cb2ba9950d010ba95bb0553 /drivers/xen | |
parent | 5c13f8067745efc15f6ad0158b58d57c44104c25 (diff) | |
download | linux-b5e579232d635b79a3da052964cb357ccda8d9ea.tar.xz |
xen/events: fix unmask_evtchn for PV on HVM guests
When unmask_evtchn is called, if we already have an event pending, we
just set evtchn_pending_sel waiting for local_irq_enable to be called.
That is because PV guests set the irq_enable pvops to
xen_irq_enable_direct in xen_setup_vcpu_info_placement:
xen_irq_enable_direct is implemented in assembly in
arch/x86/xen/xen-asm.S and call xen_force_evtchn_callback if
XEN_vcpu_info_pending is set.
However HVM guests (and ARM guests) do not change or do not have the
irq_enable pvop, so evtchn_unmask cannot work properly for them.
Considering that having the pending_irq bit set when unmask_evtchn is
called is not very common, and it is simpler to keep the
native_irq_enable implementation for HVM guests (and ARM guests), the
best thing to do is just use the EVTCHNOP_unmask hypercall (Xen
re-injects pending events in response).
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r-- | drivers/xen/events.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 7595581..36bf17d 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -373,11 +373,22 @@ static void unmask_evtchn(int port) { struct shared_info *s = HYPERVISOR_shared_info; unsigned int cpu = get_cpu(); + int do_hypercall = 0, evtchn_pending = 0; BUG_ON(!irqs_disabled()); - /* Slow path (hypercall) if this is a non-local port. */ - if (unlikely(cpu != cpu_from_evtchn(port))) { + if (unlikely((cpu != cpu_from_evtchn(port)))) + do_hypercall = 1; + else + evtchn_pending = sync_test_bit(port, &s->evtchn_pending[0]); + + if (unlikely(evtchn_pending && xen_hvm_domain())) + do_hypercall = 1; + + /* Slow path (hypercall) if this is a non-local port or if this is + * an hvm domain and an event is pending (hvm domains don't have + * their own implementation of irq_enable). */ + if (do_hypercall) { struct evtchn_unmask unmask = { .port = port }; (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask); } else { @@ -390,7 +401,7 @@ static void unmask_evtchn(int port) * 'hw_resend_irq'. Just like a real IO-APIC we 'lose * the interrupt edge' if the channel is masked. */ - if (sync_test_bit(port, &s->evtchn_pending[0]) && + if (evtchn_pending && !sync_test_and_set_bit(port / BITS_PER_LONG, &vcpu_info->evtchn_pending_sel)) vcpu_info->evtchn_upcall_pending = 1; |