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path: root/drivers/char/hw_random/virtio-rng.c
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2019-04-05hwrng: virtio - Avoid repeated init of completionDavid Tolnay1-1/+1
[ Upstream commit aef027db48da56b6f25d0e54c07c8401ada6ce21 ] 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 f7f510ec1957 ("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 08e53fbdb85c ("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2015-01-26hwrng: virtio - drop extra empty lineMichael S. Tsirkin1-1/+0
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>
2014-10-18Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds1-6/+9
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 ...
2014-10-15virtio-rng: refactor probe error handlingMichael S. Tsirkin1-6/+9
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>
2014-09-11virtio-rng: skip reading when we start to remove the deviceAmos Kong1-0/+5
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>
2014-09-11virtio-rng: fix stuck of hot-unplugging busy deviceAmos Kong1-0/+2
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>
2014-08-15virtio: rng: add derating factor for use by hwrng coreAmit Shah1-0/+1
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>
2014-07-27Revert "hwrng: virtio - ensure reads happen after successful probe"Amit Shah1-9/+0
This reverts commit e052dbf554610e2104c5a7518c4d8374bed701bb. 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>
2014-07-27virtio: rng: delay hwrng_register() till driver is readyAmit Shah1-10/+15
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>
2014-07-27virtio: rng: re-arrange struct elements for better packingAmit Shah1-2/+2
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>
2014-07-27virtio: rng: remove unused struct elementAmit Shah1-1/+0
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>
2014-07-14hwrng: virtio - ensure reads happen after successful probeAmit Shah1-0/+10
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>
2014-05-19virtio-rng: fixes for device registration/unregistrationSasha Levin1-18/+23
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>
2014-05-19virtio-rng: fix boot with virtio-rng deviceSasha Levin1-1/+1
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: 08e53fbdb85c0f6f45c0f7c1ea3defc1752a95ce
2014-05-14virtio-rng: support multiple virtio-rng devicesAmos Kong1-39/+63
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>
2014-03-13virtio-rng: don't crash if virtqueue is broken.Rusty Russell1-2/+1
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>
2013-09-23virtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PMAaron Lu1-2/+2
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>
2013-05-03Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds1-1/+1
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 ...
2013-03-20virtio_rng: use simplified virtqueue accessors.Rusty Russell1-1/+1
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>
2013-03-08virtio: rng: disallow multiple device registrations, fixes crashesAmit Shah1-2/+11
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
2013-02-13virtio: use module_virtio_driver.Rusty Russell1-12/+1
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-01-04Drivers: char: remove __dev* attributes.Greg Kroah-Hartman1-1/+1
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>
2012-11-22char: remove use of __devexitBill Pemberton1-1/+1
CONFIG_HOTPLUG is going away as an option so __devexit is no longer needed. Signed-off-by: Bill 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-30virtio: rng: s3/s4 supportAmit Shah1-0/+17
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>
2012-07-30virtio: rng: split out common code in probe / remove for s3/s4 opsAmit Shah1-2/+12
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>
2012-07-30virtio: rng: don't wait on host when module is going awayAmit Shah1-0/+1
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>
2012-07-30virtio: rng: allow tasks to be killed that are waiting for rng inputAmit Shah1-1/+4
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>
2012-01-12virtio: rename virtqueue_add_buf_gfp to virtqueue_add_bufRusty Russell1-1/+1
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>
2011-11-01drivers/char: Add module.h to those who were using it implicitlyPaul Gortmaker1-0/+1
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>
2010-05-19virtio-rng: use virtqueue_xxx wrappersMichael S. Tsirkin1-3/+3
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>
2010-01-16virtio: fix section mismatch warningsJeff Mahoney1-3/+3
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>
2009-12-01hwrng: virtio-rng - Convert to new APIIan Molton1-51/+27
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>
2009-10-22move virtrng_remove to .devexit.textUwe Kleine-König1-1/+1
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>
2009-10-22virtio: let header files include virtio_ids.hChristian Borntraeger1-1/+0
Rusty, commit 3ca4f5ca73057a617f9444a91022d7127041970a 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>
2009-09-23virtio: add virtio IDs fileFernando Luis Vazquez Cao1-0/+1
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>
2009-09-23virtio: make add_buf return capacity remainingRusty Russell1-1/+1
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>
2009-06-12virtio: handle short buffers in virtio_rng.Rusty Russell1-8/+16
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>
2009-06-12virtio: find_vqs/del_vqs virtio operationsMichael S. Tsirkin1-3/+3
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)
2009-06-12virtio: add names to virtqueue struct, mapping from devices to queues.Rusty Russell1-1/+1
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: Rusty Russell <rusty@rustcorp.com.au>
2009-04-25virtio-rng: Remove false BUG for spurious callbacksChristian Borntraeger1-2/+2
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: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-30virtio: An entropy device, as suggested by hpa.Rusty Russell1-0/+155
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: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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