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: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NGuenther Hutzl <hutzl@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

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: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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: NPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This more accurately reflects what these drivers actually do.
Suggested-by: NPaolo Bonzini <pbonzini@redhat.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Eric noticed problems with vhost-scsi and virtio-ccw: vhost-scsi
complained about overwriting values in the config space, which
was triggered by a broken implementation of virtio-ccw's config
get/set routines. It was probably sheer luck that we did not hit
this before.

When writing a value to the config space, the WRITE_CONF ccw will
always write from the beginning of the config space up to and
including the value to be set. If the config space up to the value
has not yet been retrieved from the device, however, we'll end up
overwriting values. Keep track of the known config space and update
if needed to avoid this.

Moreover, READ_CONF will only read the number of bytes it has been
instructed to retrieve, so we must not copy more than that to the
buffer, or we might overwrite trailing values.
Reported-by: NEric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NEric Farman <farman@linux.vnet.ibm.com>
Tested-by: NEric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

As of last patch, virtio_device_is_legacy_only is always false,
drop the test from virtio ccw.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (slight reword)

We previously tried to use device even if finalize_features failed, but
that's wrong since driver and device are now out of sync.

Fail probe if we detect failures during finalize_features.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We never negotiate revision > 1, but just to
make this code more likely to work when we do,
require VERSION_1 with any revision >= 1.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>

What does it mean if rev 1 device does not set
VIRTIO_F_VERSION_1? E.g. is it native endian?

Let's not even try to drive such devices:
fail attempts to finalize features.
virtio core will detect this and bail out.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This will make it easy for transports to validate features and return
failure.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Legacy balloon device doesn't pretend to support revision 1 or 64 bit
features.

But just in case someone implements a broken one that does, let's not
even try to drive legacy only devices using revision 1, and let's not
give them a chance to say they support VIRTIO_F_VERSION_1 by not reading
or writing high feature bits.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Now that virtio-ccw has everything needed to support virtio 1.0 in
place, try to enable it if the host supports it.
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Gracefully handle failure to write device status.
We really should handle other errors as well, but this one is needed for
virtio 1.0 compliance.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

The CCW_CMD_SET_VQ command has a different format for revision 1+
devices, allowing to specify a more complex virtqueue layout. For
now, we stay however with the old layout and simply use the new
command format for virtio-1 devices.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>

With the new SET-VIRTIO-REVISION command of the virtio 1.0 standard, we
can now negotiate the virtio-ccw revision after setting a channel online.

Note that we don't negotiate version 1 yet.

[Cornelia Huck: reworked revision loop a bit]
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Negotiate full 64 bit features.
Change u32 to u64, make sure to use 1ULL everywhere.

Note: devices guarantee that VERSION_1 is clear unless
revision 1 is negotiated.

Note: We don't need to re-setup the ccw, but we do it
for clarity.

Based on patches by Rusty, Thomas Huth and Cornelia.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDavid Hildebrand <dahi@linux.vnet.ibm.com>

At this point, no transports set any of the high 32 feature bits.
Since transports generally can't (yet) cope with such bits, add BUG_ON
checks to make sure they are not set by mistake.

Based on rproc patch by Rusty.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Change u32 to u64, and use BIT_ULL and 1ULL everywhere.

Note: transports are unchanged, and only set low 32 bit.
This guarantees that no transport sets e.g. VERSION_1
by mistake without proper support.

Based on patch by Rusty.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

It seemed like a good idea to use bitmap for features
in struct virtio_device, but it's actually a pain,
and seems to become even more painful when we get more
than 32 feature bits.  Just change it to a u32 for now.

Based on patch by Rusty.
Suggested-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Fix this warning:
drivers/s390/kvm/virtio_ccw.c: In function ‘virtio_ccw_int_handler’:
drivers/s390/kvm/virtio_ccw.c:891:24: warning: unused variable ‘drv’ [-Wunused-variable]
    struct virtio_driver *drv;
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Replace duplicated code in all transports with a single wrapper in
virtio.c.

The only functional change is in virtio_mmio.c: if a buggy device sends
us an interrupt before driver is set, we previously returned IRQ_NONE,
now we return IRQ_HANDLED.

As this must not happen in practice, this does not look like a big deal.

See also commit 3fff0179
	virtio-pci: do not oops on config change if driver not loaded.
for the original motivation behind the driver check.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

When a device is lost, the common I/O layer calls the notification
handler with CIO_GONE: In that event, flag device_lost as true.

In case the device had been flagged as lost when the remove/offline callbacks
are called, call the new virtio_break_device() function prior to invoking
device_unregister(). This avoids hangs of I/O triggered via the device
unregistration callbacks.
Signed-off-by: NHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

During set offline processing virtio_grab_drvdata() incorrectly
calls dev_set_drvdata() to remove the virtio_ccw_device from the
parent ccw_device's driver data. This is wrong and ends up in a
hang during virtio_ccw_reset(), as the interrupt handler still
has need of the virtio_ccw_device.

A new field 'going_away' is introduced in struct virtio_ccw_device
to control the usage of the ccw_device's driver data pointer in
virtio_grab_drvdata().
Signed-off-by: NHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Implement the new CCW_CMD_SET_IND_ADAPTER command and try to enable
adapter interrupts for every device on the first startup. If the host
does not support adapter interrupts, fall back to normal I/O interrupts.

virtio-ccw adapter interrupts use the same isc as normal I/O subchannels
and share a summary indicator for all devices sharing the same indicator
area.

Indicator bits for the individual virtqueues may be contained in the same
indicator area for different devices.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The interrupt handler virtio_ccw_int_handler() using the vcdev pointer
is protected by the ccw_device lock. Resetting the pointer within the
ccw_device structure should be done when holding this lock.

Also resetting the vcdev pointer (under the ccw_device lock) prior to
freeing the vcdev pointer memory removes a critical path.
Signed-off-by: NHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

A command reject for a ccw may happen if we run on a host not supporting
a certain feature. We want to be able to handle this as special case of
command failure, so let's split this off from the generic -EIO error code.
Reviewed-by: NThomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host notification seems to be one
prerequisite in order to be able to handle such errors in the context
where the kick is triggered.

This patch changes the notify API. The notify function must return a
bool return value. It returns false if the host notification failed.
Signed-off-by: NHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

ccw_io_helper neglected to reset vcdev->err after a new channel
program had been successfully started, resulting in stale errors
delivered after one I/O failed. Reset the error after a new
channel program has been successfully started with no old I/O
pending.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

You can access it directly now, since 3.8: v3.7-rc1-13-g06ca287d
'virtio: move queue_index and num_free fields into core struct
virtqueue.'

Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Export the virtio-ccw api in a header for usage by other code.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Lookups by channel/vq pair on host during virtio notifications might be
expensive.  Interpret hypercall return value as a cookie which host can
use to do device lookups for the next notification more efficiently.

[CH: Fix line > 80 chars]
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

virtio_ccw_setup_vq() failed to unwind correctly on errors. In
particular, it failed to delete the virtqueue on errors, leading to
list corruption when virtio_ccw_del_vqs() iterated over a virtqueue
that had not been added to the vcdev's list.

Fix this with redoing the error unwinding in virtio_ccw_setup_vq(),
using a single path for all errors.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>

In rare cases a virtio command might try to issue a ccw before a former
ccw was answered with a tsch. This will cause CC=2 (busy). Lets just
retry in that case.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Dynamically allocate any data structures like ccw used when
doing channel I/O. Otherwise, we'd need to add extra serialization
for the different callbacks using the same data structures.
Reported-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>

Add a driver for kvm guests that matches virtual ccw devices provided
by the host as virtio bridge devices.

These virtio-ccw devices use a special set of channel commands in order
to perform virtio functions.
Reviewed-by: NMarcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGleb Natapov <gleb@redhat.com>