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commit 78b1a52e05c9db11d293342e8d6d8a230a04b4e7 upstream.
While ccw_io_helper() seems like intended to be exclusive in a sense that
it is supposed to facilitate I/O for at most one thread at any given
time, there is actually nothing ensuring that threads won't pile up at
vcdev->wait_q. If they do, all threads get woken up and see the status
that belongs to some other request than their own. This can lead to bugs.
For an example see:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788432
This race normally does not cause any problems. The operations provided
by struct virtio_config_ops are usually invoked in a well defined
sequence, normally don't fail, and are normally used quite infrequent
too.
Yet, if some of the these operations are directly triggered via sysfs
attributes, like in the case described by the referenced bug, userspace
is given an opportunity to force races by increasing the frequency of the
given operations.
Let us fix the problem by ensuring, that for each device, we finish
processing the previous request before starting with a new one.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reported-by: Colin Ian King <colin.king@canonical.com>
Cc: stable@vger.kernel.org
Message-Id: <20180925121309.58524-3-pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2448a299ec416a80f699940a86f4a6d9a4f643b1 upstream.
Currently we have a race on vcdev->config in virtio_ccw_get_config() and
in virtio_ccw_set_config().
This normally does not cause problems, as these are usually infrequent
operations. However, for some devices writing to/reading from the config
space can be triggered through sysfs attributes. For these, userspace can
force the race by increasing the frequency.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Cc: stable@vger.kernel.org
Message-Id: <20180925121309.58524-2-pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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SET_IND takes as a payload the _address_ of the indicators, meaning
that we have one of the rare cases where kmalloc(sizeof(&...)) is
actually correct. Let's clarify that with a comment.
The count for the ccw, however, was only correct because the
indicators are 64 bit. Let's use the correct value.
Reported-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Use dev_to_virtio() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Message-Id: <912bf59bd3a48f2d4d4994681e898dc084fe29d3.1451484163.git.geliangtang@163.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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checkpatch.pl wants arrays of strings declared as follows:
static const char * const names[] = { "vq-1", "vq-2", "vq-3" };
Currently the find_vqs() function takes a const char *names[] argument
so passing checkpatch.pl's const char * const names[] results in a
compiler error due to losing the second const.
This patch adjusts the find_vqs() prototype and updates all virtio
transports. This makes it possible for virtio_balloon.c, virtio_input.c,
virtgpu_kms.c, and virtio_rpmsg_bus.c to use the checkpatch.pl-friendly
type.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
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The common I/O layer may pass an error value as the irb in the device's
interrupt handler (for classic channel I/O). This won't happen in
current virtio-ccw implementations, but it's better to be safe than
sorry.
Let's just return the error conveyed by the irb and clear any possible
pending I/O indications.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Introduce /sys/debug/kernel/diag_stat with a statistic how many diagnose
calls have been done by each CPU in the system.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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In virtio_ccw_read_vq_conf() the return value of ccw_io_helper()
was not checked.
If the configuration could not be read properly, we'd wrongly assume a
queue size of 0.
Let's propagate any I/O error to virtio_ccw_setup_vq() so it may
properly fail.
Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Pull virtio/vhost fixes from Michael Tsirkin:
"Bugfixes and documentation fixes.
Igor's patch that allows users to tweak memory table size is
borderline, but it does fix known crashes, so I merged it"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vhost: add max_mem_regions module parameter
vhost: extend memory regions allocation to vmalloc
9p/trans_virtio: reset virtio device on remove
virtio/s390: rename drivers/s390/kvm -> drivers/s390/virtio
MAINTAINERS: separate section for s390 virtio drivers
virtio: define virtio_pci_cfg_cap in header.
virtio: Fix typecast of pointer in vring_init()
virtio scsi: fix unused variable warning
vhost: use binary search instead of linear in find_region()
virtio_net: document VIRTIO_NET_CTRL_GUEST_OFFLOADS
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This more accurately reflects what these drivers actually do.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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