Code like
	vi->vq = NULL;
	kfree(vi)
does not make sense.

Clean it up, use goto error labels for cleanup.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Before we really unregister the hwrng device, reading will get stuck if
the virtio device is reset. We should return error for reading when we
start to remove the device.
Signed-off-by: NAmos Kong <akong@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

When we try to hot-remove a busy virtio-rng device from QEMU monitor,
the device can't be hot-removed. Because virtio-rng driver hangs at
wait_for_completion_killable().

This patch exits the waiting by completing have_data completion before
unregistering, resets data_avail to avoid the hwrng core use wrong
buffer bytes.
Signed-off-by: NAmos Kong <akong@redhat.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The khwrngd thread is started when a hwrng device of sufficient
quality is registered.  The virtio-rng device is backed by the
hypervisor, and we trust the hypervisor to provide real entropy.

A malicious or badly-implemented hypervisor is a scenario that's
irrelevant -- such a setup is bound to cause all sorts of badness, and a
compromised hwrng is the least of the user's worries.

Given this, we might as well assume that the quality of randomness we
receive is perfectly trustworthy.  Hence, we use 100% for the factor,
indicating maximum confidence in the source.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Reviewed-by: NH. Peter Anvin <hpa@linux.intel.com>
Reviewed-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This reverts commit e052dbf5.

Now that we use the virtio ->scan() function to register with the hwrng
core, we will not get read requests till probe is successfully finished.

So revert the workaround we had in place to refuse read requests while
we were not yet setup completely.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Instead of calling hwrng_register() in the probe routing, call it in the
scan routine.  This ensures that when hwrng_register() is successful,
and it requests a few random bytes to seed the kernel's pool at init,
we're ready to service that request.

This will also enable us to remove the workaround added previously to
check whether probe was completed, and only then ask for data from the
host.  The revert follows in the next commit.

There's a slight behaviour change here on unsuccessful hwrng_register().
Previously, when hwrng_register() failed, the probe() routine would
fail, and the vqs would be torn down, and driver would be marked not
initialized.  Now, the vqs will remain initialized, driver would be
marked initialized as well, but won't be available in the list of RNGs
available to hwrng core.  To fix the failures, the procedure remains the
same, i.e. unload and re-load the module, and hope things succeed the
next time around.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Re-arrange the elements of the virtrng_info struct to pack it better.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

vdev is unused in struct virtrng_info, remove it.

CC: Amos Kong <akong@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The hwrng core asks for random data in the hwrng_register() call itself
from commit d9e79726.  This doesn't play well with virtio -- the
DRIVER_OK bit is only set by virtio core on a successful probe, and
we're not yet out of our probe routine when this call is made.  This
causes the host to not acknowledge any requests we put in the virtqueue,
and the insmod or kernel boot process just waits for data to arrive from
the host, which never happens.

CC: Kees Cook <keescook@chromium.org>
CC: Jason Cooper <jason@lakedaemon.net>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: <stable@vger.kernel.org> # For v3.15+
Reviewed-by: NJason Cooper <jason@lakedaemon.net>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

There are several fixes in this patch (mostly because it's hard
splitting them up):

 - Revert the name field in struct hwrng back to 'const'. Also, don't
do an extra kmalloc for the name - just wasteful.
 - Deal with allocation failures properly.
 - Use IDA to allocate device number instead of brute forcing one.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Commit "virtio-rng: support multiple virtio-rng devices" has broken
boot with a virtio-rng device because the 'init' callback of the
virtio-rng device was left unitialized to garbage, and got called
by the hwrng infrastructure, killing the guest on boot.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Fixes: 08e53fbd

Current hwrng core supports to register multiple hwrng devices,
and there is only one device really works in the same time.
QEMU alsu supports to have multiple virtio-rng backends.

This patch changes virtio-rng driver to support multiple
virtio-rng devices.

]# cat /sys/class/misc/hw_random/rng_available
virtio_rng.0 virtio_rng.1
]# cat /sys/class/misc/hw_random/rng_current
virtio_rng.0
]# echo -n virtio_rng.1 > /sys/class/misc/hw_random/rng_current
]# dd if=/dev/hwrng of=/dev/null
Signed-off-by: NAmos Kong <akong@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

A bad implementation of virtio might cause us to mark the virtqueue
broken: we'll dev_err() in that case, and the device is useless, but
let's not BUG().
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We never add buffers with input and output parts, so use the new accessors.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NAsias He <asias@redhat.com>

The code currently only supports one virtio-rng device at a time.
Invoking guests with multiple devices causes the guest to blow up.

Check if we've already registered and initialised the driver.  Also
cleanup in case of registration errors or hot-unplug so that a new
device can be used.
Reported-by: NPeter Krempa <pkrempa@redhat.com>
Reported-by: <yunzheng@redhat.com>
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org

Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, __devinitdata,
__devinitconst, and __devexit from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: NBill Pemberton <wfp5p@virginia.edu>
Cc: David Airlie <airlied@linux.ie>
Cc: Olof Johansson <olof@lixom.net>
Cc: Mattia Dongili <malattia@linux.it>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Cc: Rajiv Andrade <mail@srajiv.net>
Cc: Marcel Selhorst <tpmdd@selhorst.net>
Cc: Sirrix AG <tpmdd@sirrix.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: openipmi-developer@lists.sourceforge.net
Cc: platform-driver-x86@vger.kernel.org
Cc: tpmdd-devel@lists.sourceforge.net
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Unregister from the hwrng interface and remove the vq before entering
the S3 or S4 states.  Add the vq and re-register with hwrng on restore.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The freeze/restore s3/s4 operations will use code that's common to the
probe and remove routines.  Put the common code in separate funcitons.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

No use waiting for input from host when the module is being removed.
We're going to remove the vq in the next step anyway, so just perform
any other steps for cleanup (currently none).
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Use wait_for_completion_killable() instead of wait_for_completion() when
waiting for the host to send us entropy.  Without this,

  # cat /dev/hwrng
  ^C

just hangs.
Signed-off-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

A pending cleanup will mean that module.h won't be implicitly
everywhere anymore.  Make sure the modular drivers in char are
actually calling out for <module.h> explicitly in advance.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Switch virtio-rng to new virtqueue_xxx wrappers.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Fix fixes the following warnings by renaming the driver structures to be
suffixed with _driver.

WARNING: drivers/virtio/virtio_balloon.o(.data+0x88): Section mismatch in reference from the variable virtio_balloon to the function .devexit.text:virtballoon_remove()

WARNING: drivers/char/hw_random/virtio-rng.o(.data+0x88): Section mismatch in reference from the variable virtio_rng to the function .devexit.text:virtrng_remove()
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch converts virtio-rng to the new hw_rng API.

In the process it fixes a previously untriggered buffering bug where the
buffer is not drained correctly if it has a non-multiple-of-4 length.

Performance has improved under qemu-kvm testing also.
Signed-off-by: NIan Molton <ian.molton@collabora.co.uk>
Acked-by: NMatt Mackall <mpm@selenic.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The function virtrng_remove is used only wrapped by __devexit_p so define
it using __devexit.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Rusty,

commit 3ca4f5ca
    virtio: add virtio IDs file
moved all device IDs into a single file. While the change itself is
a very good one, it can break userspace applications. For example
if a userspace tool wanted to get the ID of virtio_net it used to
include virtio_net.h. This does no longer work, since virtio_net.h
does not include virtio_ids.h.
This patch moves all "#include <linux/virtio_ids.h>" from the C
files into the header files, making the header files compatible with
the old ones.

In addition, this patch exports virtio_ids.h to userspace.

CC: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Virtio IDs are spread all over the tree which makes assigning new IDs
bothersome. Putting them together should make the process less error-prone.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This API change means that virtio_net can tell how much capacity
remains for buffers.  It's necessarily fuzzy, since
VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors
in one, *if* we can kmalloc.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

If the device fills less than 4 bytes of our random buffer, we'll
BUG_ON.  It's nicer to handle the case where it partially fills the
buffer (the protocol doesn't explicitly bad that).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This replaces find_vq/del_vq with find_vqs/del_vqs virtio operations,
and updates all drivers. This is needed for MSI support, because MSI
needs to know the total number of vectors upfront.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ lguest/9p compile fixes)

Add a linked list of all virtqueues for a virtio device: this helps for
debugging and is also needed for upcoming interface change.

Also, add a "name" field for clearer debug messages.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The virtio-rng drivers checks for spurious callbacks. Since
callbacks can be implemented via shared interrupts (e.g. PCI) this
could lead to guest kernel oopses with lots of virtio devices.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Note that by itself, having a "hardware" random generator does very
little: you should probably run "rngd" in your guest to feed this into
the kernel entropy pool.

Included:
	virtio_rng: dont use vmalloced addresses for virtio

	If virtio_rng is build as a module, random_data is an address
	in vmalloc space. As virtio expects guest real addresses, this
	can cause any kind of funny behaviour, so lets allocate
	random_data dynamically with kmalloc.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>