linux/virt/kvm
Xiubo Li caf1ff26e1 kvm: Fix irq route entries exceeding KVM_MAX_IRQ_ROUTES
These days, we experienced one guest crash with 8 cores and 3 disks,
with qemu error logs as bellow:

qemu-system-x86_64: /build/qemu-2.0.0/kvm-all.c:984:
kvm_irqchip_commit_routes: Assertion `ret == 0' failed.

And then we found one patch(bdf026317d) in qemu tree, which said
could fix this bug.

Execute the following script will reproduce the BUG quickly:

irq_affinity.sh
========================================================================

vda_irq_num=25
vdb_irq_num=27
while [ 1 ]
do
    for irq in {1,2,4,8,10,20,40,80}
        do
            echo $irq > /proc/irq/$vda_irq_num/smp_affinity
            echo $irq > /proc/irq/$vdb_irq_num/smp_affinity
            dd if=/dev/vda of=/dev/zero bs=4K count=100 iflag=direct
            dd if=/dev/vdb of=/dev/zero bs=4K count=100 iflag=direct
        done
done
========================================================================

The following qemu log is added in the qemu code and is displayed when
this bug reproduced:

kvm_irqchip_commit_routes: max gsi: 1008, nr_allocated_irq_routes: 1024,
irq_routes->nr: 1024, gsi_count: 1024.

That's to say when irq_routes->nr == 1024, there are 1024 routing entries,
but in the kernel code when routes->nr >= 1024, will just return -EINVAL;

The nr is the number of the routing entries which is in of
[1 ~ KVM_MAX_IRQ_ROUTES], not the index in [0 ~ KVM_MAX_IRQ_ROUTES - 1].

This patch fix the BUG above.

Cc: stable@vger.kernel.org
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com>
Signed-off-by: Zhang Zhuoyu <zhangzhuoyu@cmss.chinamobile.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 09:38:15 +02:00
..
arm KVM: arm/arm64: vgic-new: Removel harmful BUG_ON 2016-06-02 11:52:21 +02:00
Kconfig KVM: halt_polling: provide a way to qualify wakeups during poll 2016-05-13 17:29:23 +02:00
async_pf.c Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-20 19:08:56 -07:00
async_pf.h KVM: fix checkpatch.pl errors in kvm/async_pf.h 2015-06-19 17:16:25 +02:00
coalesced_mmio.c KVM: move iodev.h from virt/kvm/ to include/kvm 2015-03-26 21:43:12 +00:00
coalesced_mmio.h KVM: make the declaration of functions within 80 characters 2015-09-14 18:43:19 +02:00
eventfd.c kvm: Conditionally register IRQ bypass consumer 2016-05-11 22:37:55 +02:00
irqchip.c KVM: irqfd: fix NULL pointer dereference in kvm_irq_map_gsi 2016-06-02 17:38:50 +02:00
kvm_main.c kvm: Fix irq route entries exceeding KVM_MAX_IRQ_ROUTES 2016-06-16 09:38:15 +02:00
vfio.c KVM: count number of assigned devices 2015-07-10 13:25:26 +02:00
vfio.h kvm: vfio: fix unregister kvm_device_ops of vfio 2014-10-24 13:30:47 +02:00