ff1e22e7a6
Moving an unmasked irq may result in irq handler being invoked on both
source and target CPUs.
With 2-level this can happen as follows:
On source CPU:
evtchn_2l_handle_events() ->
generic_handle_irq() ->
handle_edge_irq() ->
eoi_pirq():
irq_move_irq(data);
/***** WE ARE HERE *****/
if (VALID_EVTCHN(evtchn))
clear_evtchn(evtchn);
If at this moment target processor is handling an unrelated event in
evtchn_2l_handle_events()'s loop it may pick up our event since target's
cpu_evtchn_mask claims that this event belongs to it *and* the event is
unmasked and still pending. At the same time, source CPU will continue
executing its own handle_edge_irq().
With FIFO interrupt the scenario is similar: irq_move_irq() may result
in a EVTCHNOP_unmask hypercall which, in turn, may make the event
pending on the target CPU.
We can avoid this situation by moving and clearing the event while
keeping event masked.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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| .. | ||
| events | ||
| xen-pciback | ||
| xenbus | ||
| xenfs | ||
| Kconfig | ||
| Makefile | ||
| acpi.c | ||
| balloon.c | ||
| biomerge.c | ||
| cpu_hotplug.c | ||
| dbgp.c | ||
| efi.c | ||
| evtchn.c | ||
| fallback.c | ||
| features.c | ||
| gntalloc.c | ||
| gntdev.c | ||
| grant-table.c | ||
| manage.c | ||
| mcelog.c | ||
| pci.c | ||
| pcpu.c | ||
| platform-pci.c | ||
| preempt.c | ||
| privcmd.c | ||
| privcmd.h | ||
| swiotlb-xen.c | ||
| sys-hypervisor.c | ||
| time.c | ||
| tmem.c | ||
| xen-acpi-cpuhotplug.c | ||
| xen-acpi-memhotplug.c | ||
| xen-acpi-pad.c | ||
| xen-acpi-processor.c | ||
| xen-balloon.c | ||
| xen-scsiback.c | ||
| xen-selfballoon.c | ||
| xen-stub.c | ||
| xlate_mmu.c | ||