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path: root/drivers/s390/cio/vfio_ccw_drv.c
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* vfio-ccw: Prevent quiesce function going into an infinite loopFarhan Ali2019-04-241-14/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The quiesce function calls cio_cancel_halt_clear() and if we get an -EBUSY we go into a loop where we: - wait for any interrupts - flush all I/O in the workqueue - retry cio_cancel_halt_clear During the period where we are waiting for interrupts or flushing all I/O, the channel subsystem could have completed a halt/clear action and turned off the corresponding activity control bits in the subchannel status word. This means the next time we call cio_cancel_halt_clear(), we will again start by calling cancel subchannel and so we can be stuck between calling cancel and halt forever. Rather than calling cio_cancel_halt_clear() immediately after waiting, let's try to disable the subchannel. If we succeed in disabling the subchannel then we know nothing else can happen with the device. Suggested-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Message-Id: <4d5a4b98ab1b41ac6131b5c36de18b76c5d66898.1555449329.git.alifm@linux.ibm.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Acked-by: Halil Pasic <pasic@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio-ccw: Do not call flush_workqueue while holding the spinlockFarhan Ali2019-04-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we call flush_workqueue while holding the subchannel spinlock. But flush_workqueue function can go to sleep, so do not call the function while holding the spinlock. Fixes the following bug: [ 285.203430] BUG: scheduling while atomic: bash/14193/0x00000002 [ 285.203434] INFO: lockdep is turned off. .... [ 285.203485] Preemption disabled at: [ 285.203488] [<000003ff80243e5c>] vfio_ccw_sch_quiesce+0xbc/0x120 [vfio_ccw] [ 285.203496] CPU: 7 PID: 14193 Comm: bash Tainted: G W .... [ 285.203504] Call Trace: [ 285.203510] ([<0000000000113772>] show_stack+0x82/0xd0) [ 285.203514] [<0000000000b7a102>] dump_stack+0x92/0xd0 [ 285.203518] [<000000000017b8be>] __schedule_bug+0xde/0xf8 [ 285.203524] [<0000000000b95b5a>] __schedule+0x7a/0xc38 [ 285.203528] [<0000000000b9678a>] schedule+0x72/0xb0 [ 285.203533] [<0000000000b9bfbc>] schedule_timeout+0x34/0x528 [ 285.203538] [<0000000000b97608>] wait_for_common+0x118/0x1b0 [ 285.203544] [<0000000000166d6a>] flush_workqueue+0x182/0x548 [ 285.203550] [<000003ff80243e6e>] vfio_ccw_sch_quiesce+0xce/0x120 [vfio_ccw] [ 285.203556] [<000003ff80245278>] vfio_ccw_mdev_reset+0x38/0x70 [vfio_ccw] [ 285.203562] [<000003ff802458b0>] vfio_ccw_mdev_remove+0x40/0x78 [vfio_ccw] [ 285.203567] [<000003ff801a499c>] mdev_device_remove_ops+0x3c/0x80 [mdev] [ 285.203573] [<000003ff801a4d5c>] mdev_device_remove+0xc4/0x130 [mdev] [ 285.203578] [<000003ff801a5074>] remove_store+0x6c/0xa8 [mdev] [ 285.203582] [<000000000046f494>] kernfs_fop_write+0x14c/0x1f8 [ 285.203588] [<00000000003c1530>] __vfs_write+0x38/0x1a8 [ 285.203593] [<00000000003c187c>] vfs_write+0xb4/0x198 [ 285.203597] [<00000000003c1af2>] ksys_write+0x5a/0xb0 [ 285.203601] [<0000000000b9e270>] system_call+0xdc/0x2d8 Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Message-Id: <626bab8bb2958ae132452e1ddaf1b20882ad5a9d.1554756534.git.alifm@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio-ccw: add handling for async channel instructionsCornelia Huck2019-04-241-13/+33
| | | | | | | | | | | | | Add a region to the vfio-ccw device that can be used to submit asynchronous I/O instructions. ssch continues to be handled by the existing I/O region; the new region handles hsch and csch. Interrupt status continues to be reported through the same channels as for ssch. Acked-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Farhan Ali <alifm@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio-ccw: protect the I/O regionCornelia Huck2019-04-241-0/+3
| | | | | | | | | | | Introduce a mutex to disallow concurrent reads or writes to the I/O region. This makes sure that the data the kernel or user space see is always consistent. The same mutex will be used to protect the async region as well. Reviewed-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio: ccw: only free cp on final interruptCornelia Huck2019-03-111-2/+6
| | | | | | | | | | | | | | | | | When we get an interrupt for a channel program, it is not necessarily the final interrupt; for example, the issuing guest may request an intermediate interrupt by specifying the program-controlled-interrupt flag on a ccw. We must not switch the state to idle if the interrupt is not yet final; even more importantly, we must not free the translated channel program if the interrupt is not yet final, or the host can crash during cp rewind. Fixes: e5f84dbaea59 ("vfio: ccw: return I/O results asynchronously") Cc: stable@vger.kernel.org # v4.12+ Reviewed-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio: ccw: Register mediated device once all structures are initializedPierre Morel2018-11-131-4/+4
| | | | | | | | | | | Let's register the mediated device when all the data structures which could be used are initialized. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Message-Id: <1540487720-11634-3-git-send-email-pmorel@linux.ibm.com> Acked-by: Halil Pasic <pasic@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* s390/cio: make vfio_ccw_io_region staticSebastian Ott2018-11-131-1/+1
| | | | | | | | | | Fix the following sparse warning: drivers/s390/cio/vfio_ccw_drv.c:25:19: warning: symbol 'vfio_ccw_io_region' was not declared. Should it be static? Signed-off-by: Sebastian Ott <sebott@linux.ibm.com> Message-Id: <alpine.LFD.2.21.1810151328570.1636@schleppi.aag-de.ibmmobiledemo.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* s390/cio: Refactor alloc of ccw_io_regionEric Farman2018-09-271-4/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If I attach a vfio-ccw device to my guest, I get the following warning on the host when the host kernel is CONFIG_HARDENED_USERCOPY=y [250757.595325] Bad or missing usercopy whitelist? Kernel memory overwrite attempt detected to SLUB object 'dma-kmalloc-512' (offset 64, size 124)! [250757.595365] WARNING: CPU: 2 PID: 10958 at mm/usercopy.c:81 usercopy_warn+0xac/0xd8 [250757.595369] Modules linked in: kvm vhost_net vhost tap xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack libcrc32c devlink tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables sunrpc dm_multipath s390_trng crc32_vx_s390 ghash_s390 prng aes_s390 des_s390 des_generic sha512_s390 sha1_s390 eadm_sch tape_3590 tape tape_class qeth_l2 qeth ccwgroup vfio_ccw vfio_mdev zcrypt_cex4 mdev vfio_iommu_type1 zcrypt vfio sha256_s390 sha_common zfcp scsi_transport_fc qdio dasd_eckd_mod dasd_mod [250757.595424] CPU: 2 PID: 10958 Comm: CPU 2/KVM Not tainted 4.18.0-derp #2 [250757.595426] Hardware name: IBM 3906 M05 780 (LPAR) ...snip regs... [250757.595523] Call Trace: [250757.595529] ([<0000000000349210>] usercopy_warn+0xa8/0xd8) [250757.595535] [<000000000032daaa>] __check_heap_object+0xfa/0x160 [250757.595540] [<0000000000349396>] __check_object_size+0x156/0x1d0 [250757.595547] [<000003ff80332d04>] vfio_ccw_mdev_write+0x74/0x148 [vfio_ccw] [250757.595552] [<000000000034ed12>] __vfs_write+0x3a/0x188 [250757.595556] [<000000000034f040>] vfs_write+0xa8/0x1b8 [250757.595559] [<000000000034f4e6>] ksys_pwrite64+0x86/0xc0 [250757.595568] [<00000000008959a0>] system_call+0xdc/0x2b0 [250757.595570] Last Breaking-Event-Address: [250757.595573] [<0000000000349210>] usercopy_warn+0xa8/0xd8 While vfio_ccw_mdev_{write|read} validates that the input position/count does not run over the ccw_io_region struct, the usercopy code that does copy_{to|from}_user doesn't necessarily know this. It sees the variable length and gets worried that it's affecting a normal kmalloc'd struct, and generates the above warning. Adjust how the ccw_io_region is alloc'd with a whitelist to remove this warning. The boundary checking will continue to do its thing. Signed-off-by: Eric Farman <farman@linux.ibm.com> Message-Id: <20180921204013.95804-3-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* s390/cio: Convert ccw_io_region to pointerEric Farman2018-09-271-1/+11
| | | | | | | | | | | | In the event that we want to change the layout of the ccw_io_region in the future[1], it might be easier to work with it as a pointer within the vfio_ccw_private struct rather than an embedded struct. [1] https://patchwork.kernel.org/comment/22228541/ Signed-off-by: Eric Farman <farman@linux.ibm.com> Message-Id: <20180921204013.95804-2-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* vfio: ccw: fix error return in vfio_ccw_sch_eventDong Jia Shi2018-05-291-1/+4
| | | | | | | | | | If the device has not been registered, or there is work pending, we should reschedule a sch_event call again. Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20180502072559.50691-1-bjsdjshi@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
* s390: cio: add SPDX identifiers to the remaining filesGreg Kroah-Hartman2017-11-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/s390/cio/ files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Cornelia Huck <cohuck@redhat.com> Cc: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/vfio_ccw: remove unused variableSebastian Ott2017-07-051-2/+0
| | | | | | | | | | | | | | Fix this set but not used warning: drivers/s390/cio/vfio_ccw_drv.c: In function 'vfio_ccw_sch_io_todo': drivers/s390/cio/vfio_ccw_drv.c:72:21: warning: variable 'sch' set but not used [-Wunused-but-set-variable] struct subchannel *sch; ^ Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/cio: introduce io_subchannel_typeSebastian Ott2017-06-121-57/+1
| | | | | | | | | | | The sysfs attributes implemented by the vfio_ccw driver are also implemented by the io_subchannel driver. Move these into a device_type which is set by the css bus. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* vfio: ccw: introduce a finite state machineDong Jia Shi2017-03-311-102/+14
| | | | | | | | | | The current implementation doesn't check if the subchannel is in a proper device state when handling an event. Let's introduce a finite state machine to manage the state/event change. Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-14-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* vfio: ccw: return I/O results asynchronouslyDong Jia Shi2017-03-311-24/+34
| | | | | | | | | | | Introduce a singlethreaded workqueue to handle the I/O interrupts. With the work added to this queue, we store the I/O results to the io_region of the subchannel, then signal the userspace program to handle the results. Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-13-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* vfio: ccw: handle ccw command requestDong Jia Shi2017-03-311-0/+114
| | | | | | | | | | | | | | We implement the basic ccw command handling infrastructure here: 1. Translate the ccw commands. 2. Issue the translated ccw commands to the device. 3. Once we get the execution result, update the guest SCSW with it. Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-9-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* vfio: ccw: register vfio_ccw to the mediated device frameworkDong Jia Shi2017-03-311-1/+11
| | | | | | | | | | | | | | To make vfio support subchannel devices, we need to leverage the mediated device framework to create a mediated device for the subchannel device. This registers the subchannel device to the mediated device framework during probe to enable mediated device creation. Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-7-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* vfio: ccw: basic implementation for vfio_ccw driverDong Jia Shi2017-03-311-0/+262
To make vfio support subchannel devices, we need a css driver for the vfio subchannels. This patch adds a basic vfio-ccw subchannel driver for this purpose. To enable VFIO for vfio-ccw, enable S390_CCW_IOMMU config option and configure VFIO as required. Acked-by: Pierre Morel <pmorel@linux.vnet.ibm.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Message-Id: <20170317031743.40128-5-bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
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