Most hw_random devices return entropy which is assumed to be of full
quality, but driver authors don't bother setting the quality knob. Some
hw_random devices return less than full quality entropy, and then driver
authors set the quality knob. Therefore, the entropy crediting should be
opt-out rather than opt-in per-driver, to reflect the actual reality on
the ground.
For example, the two Raspberry Pi RNG drivers produce full entropy
randomness, and both EDK2 and U-Boot's drivers for these treat them as
such. The result is that EFI then uses these numbers and passes the to
Linux, and Linux credits them as boot, thereby initializing the RNG.
Yet, in Linux, the quality knob was never set to anything, and so on the
chance that Linux is booted without EFI, nothing is ever credited.
That's annoying.
The same pattern appears to repeat itself throughout various drivers. In
fact, very very few drivers have bothered setting quality=1024.
Looking at the git history of existing drivers and corresponding mailing
list discussion, this conclusion tracks. There's been a decent amount of
discussion about drivers that set quality < 1024 -- somebody read and
interepreted a datasheet, or made some back of the envelope calculation
somehow. But there's been very little, if any, discussion about most
drivers where the quality is just set to 1024 or unset (or set to 1000
when the authors misunderstood the API and assumed it was base-10 rather
than base-2); in both cases the intent was fairly clear of, "this is a
hardware random device; it's fine."
So let's invert this logic. A hw_random struct's quality knob now
controls the maximum quality a driver can produce, or 0 to specify 1024.
Then, the module-wide switch called "default_quality" is changed to
represent the maximum quality of any driver. By default it's 1024, and
the quality of any particular driver is then given by:
min(default_quality, rng->quality ?: 1024);
This way, the user can still turn this off for weird reasons (and we can
replace whatever driver-specific disabling hacks existed in the past),
yet we get proper crediting for relevant RNGs.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Current virtio-rng does a entropy request before DRIVER_OK, this
violates the spec:
virtio spec requires that all drivers set DRIVER_OK
before using devices.
Further, kernel will ignore the interrupt after commit
8b4ec69d7e ("virtio: harden vring IRQ").
Fixing this by making device ready before the request.
Cc: stable@vger.kernel.org
Fixes: 8b4ec69d7e ("virtio: harden vring IRQ")
Fixes: f7f510ec19 ("virtio: An entropy device, as suggested by hpa.")
Reported-and-tested-by: syzbot+5b59d6d459306a556f54@syzkaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220608061422.38437-1-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
unregister after reset is clearly wrong - device
can be used while it's reset. There's an attempt to
protect against that using hwrng_removed but it
seems racy since access can be in progress
when the flag is set.
Just unregister, then reset seems simpler and cleaner.
NB: we might be able to drop hwrng_removed in a follow-up patch.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This will enable cleanups down the road.
The idea is to disable cbs, then add "flush_queued_cbs" callback
as a parameter, this way drivers can flush any work
queued after callbacks have been disabled.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
If we ensure we have already some data available by enqueuing
again the buffer once data are exhausted, we can return what we
have without waiting for the device answer.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Link: https://lore.kernel.org/r/20211028101111.128049-5-lvivier@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
When virtio-rng device was dropped by the hwrng core we were forced
to wait the buffer to come back from the device to not have
remaining ongoing operation that could spoil the buffer.
But now, as the buffer is internal to the virtio-rng we can release
the waiting loop immediately, the buffer will be retrieve and use
when the virtio-rng driver will be selected again.
This avoids to hang on an rng_current write command if the virtio-rng
device is blocked by a lack of entropy. This allows to select
another entropy source if the current one is empty.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Link: https://lore.kernel.org/r/20211028101111.128049-3-lvivier@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hwrng core uses two buffers that can be mixed in the
virtio-rng queue.
If the buffer is provided with wait=0 it is enqueued in the
virtio-rng queue but unused by the caller.
On the next call, core provides another buffer but the
first one is filled instead and the new one queued.
And the caller reads the data from the new one that is not
updated, and the data in the first one are lost.
To avoid this mix, virtio-rng needs to use its own unique
internal buffer at a cost of a data copy to the caller buffer.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Link: https://lore.kernel.org/r/20211028101111.128049-2-lvivier@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
id_table[] is not modified and an be made const to allow the compiler to
put it in read-only memory.
Before:
text data bss dec hex filename
1746 192 8 1946 79a drivers/char/hw_random/virtio-rng.o
After:
text data bss dec hex filename
1762 176 8 1946 79a drivers/char/hw_random/virtio-rng.o
Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
51 franklin st fifth floor boston ma 02110 1301 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 50 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091649.499889647@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The virtio-rng driver uses a completion called have_data to wait for a
virtio read to be fulfilled by the hypervisor. The completion is reset
before placing a buffer on the virtio queue and completed by the virtio
callback once data has been written into the buffer.
Prior to this commit, the driver called init_completion on this
completion both during probe as well as when registering virtio buffers
as part of a hwrng read operation. The second of these init_completion
calls should instead be reinit_completion because the have_data
completion has already been inited by probe. As described in
Documentation/scheduler/completion.txt, "Calling init_completion() twice
on the same completion object is most likely a bug".
This bug was present in the initial implementation of virtio-rng in
f7f510ec19 ("virtio: An entropy device, as suggested by hpa"). Back
then the have_data completion was a single static completion rather than
a member of one of potentially multiple virtrng_info structs as
implemented later by 08e53fbdb8 ("virtio-rng: support multiple
virtio-rng devices"). The original driver incorrectly used
init_completion rather than INIT_COMPLETION to reset have_data during
read.
Tested by running `head -c48 /dev/random | hexdump` within crosvm, the
Chrome OS virtual machine monitor, and confirming that the virtio-rng
driver successfully produces random bytes from the host.
Signed-off-by: David Tolnay <dtolnay@gmail.com>
Tested-by: David Tolnay <dtolnay@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The patch for
commit: 5c06273401
Author: Amit Shah <amit.shah@redhat.com>
Date: Sun Jul 27 07:34:01 2014 +0930
virtio: rng: delay hwrng_register() till driver is ready
moved the call to hwrng_register() out of the probe routine into the scan
routine. We need to call hwrng_register() after a suspend/restore cycle
to re-register the device, but the scan function is not invoked for the
restore. Add the call to hwrng_register() to virtio_restore().
Reviewed-by: Liam Merwick <Liam.Merwick@oracle.com>
Signed-off-by: Jim Quigley <Jim.Quigley@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
makes code look a bit prettier.
Cc: linux-crypto@vger.kernel.org.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
been sitting in MST's tree during my vacation. I changed a function name
and made one trivial change, then they spent two days in linux-next.
Thanks,
Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio updates from Rusty Russell:
"One cc: stable commit, the rest are a series of minor cleanups which
have been sitting in MST's tree during my vacation. I changed a
function name and made one trivial change, then they spent two days in
linux-next"
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (25 commits)
virtio-rng: refactor probe error handling
virtio_scsi: drop scan callback
virtio_balloon: enable VQs early on restore
virtio_scsi: fix race on device removal
virito_scsi: use freezable WQ for events
virtio_net: enable VQs early on restore
virtio_console: enable VQs early on restore
virtio_scsi: enable VQs early on restore
virtio_blk: enable VQs early on restore
virtio_scsi: move kick event out from virtscsi_init
virtio_net: fix use after free on allocation failure
9p/trans_virtio: enable VQs early
virtio_console: enable VQs early
virtio_blk: enable VQs early
virtio_net: enable VQs early
virtio: add API to enable VQs early
virtio_net: minor cleanup
virtio-net: drop config_mutex
virtio_net: drop config_enable
virtio-blk: drop config_mutex
...
Code like
vi->vq = NULL;
kfree(vi)
does not make sense.
Clean it up, use goto error labels for cleanup.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty 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: Amos Kong <akong@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rusty 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: Amos Kong <akong@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rusty 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: Amit Shah <amit.shah@redhat.com>
Reviewed-by: H. Peter Anvin <hpa@linux.intel.com>
Reviewed-by: Amos Kong <akong@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This reverts commit e052dbf554.
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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Re-arrange the elements of the virtrng_info struct to pack it better.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
vdev is unused in struct virtrng_info, remove it.
CC: Amos Kong <akong@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The hwrng core asks for random data in the hwrng_register() call itself
from commit d9e7972619. 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: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Herbert 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: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rusty 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: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: 08e53fbdb8
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: Amos Kong <akong@redhat.com>
Signed-off-by: Rusty 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: Rusty 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: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I dived into lguest again, reworking the pagetable code so we can move
the switcher page: our fixmaps sometimes take more than 2MB now...
Cheers,
Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio & lguest updates from Rusty Russell:
"Lots of virtio work which wasn't quite ready for last merge window.
Plus I dived into lguest again, reworking the pagetable code so we can
move the switcher page: our fixmaps sometimes take more than 2MB now..."
Ugh. Annoying conflicts with the tcm_vhost -> vhost_scsi rename.
Hopefully correctly resolved.
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (57 commits)
caif_virtio: Remove bouncing email addresses
lguest: improve code readability in lg_cpu_start.
virtio-net: fill only rx queues which are being used
lguest: map Switcher below fixmap.
lguest: cache last cpu we ran on.
lguest: map Switcher text whenever we allocate a new pagetable.
lguest: don't share Switcher PTE pages between guests.
lguest: expost switcher_pages array (as lg_switcher_pages).
lguest: extract shadow PTE walking / allocating.
lguest: make check_gpte et. al return bool.
lguest: assume Switcher text is a single page.
lguest: rename switcher_page to switcher_pages.
lguest: remove RESERVE_MEM constant.
lguest: check vaddr not pgd for Switcher protection.
lguest: prepare to make SWITCHER_ADDR a variable.
virtio: console: replace EMFILE with EBUSY for already-open port
virtio-scsi: reset virtqueue affinity when doing cpu hotplug
virtio-scsi: introduce multiqueue support
virtio-scsi: push vq lock/unlock into virtscsi_vq_done
virtio-scsi: pass struct virtio_scsi to virtqueue completion function
...
We never add buffers with input and output parts, so use the new accessors.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Asias 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: Peter Krempa <pkrempa@redhat.com>
Reported-by: <yunzheng@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
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: Greg 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty 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: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty 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: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph 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: Paul Gortmaker <paul.gortmaker@windriver.com>
Switch virtio-rng to new virtqueue_xxx wrappers.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty 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: Jeff Mahoney <jeffm@suse.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus 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: Ian Molton <ian.molton@collabora.co.uk>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Herbert 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: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty,
commit 3ca4f5ca73
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: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty 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: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Rusty 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: Rusty 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: Rusty 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: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ lguest/9p compile fixes)
