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There is a small window where it's possible that we could be working
on an interrupt (queued in the workqueue) and setting up a channel
program (i.e allocating memory, pinning pages, translating address).
This can lead to allocating and freeing the channel program at the
same time and can cause memory corruption.
Let's not call cp_free if we are currently processing a channel program.
The only way we know for sure that we don't have a thread setting
up a channel program is when the state is set to VFIO_CCW_STATE_CP_PENDING.
Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions")
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <62e87bf67b38dc8d5760586e7c96d400db854ebe.1562854091.git.alifm@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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Pull s390 updates from Vasily Gorbik:
- Improve stop_machine wait logic: replace cpu_relax_yield call in
generic stop_machine function with a weak stop_machine_yield
function. This is overridden on s390, which yields the current cpu to
the neighbouring cpu after a couple of retries, instead of blindly
giving up the cpu to the hipervisor. This significantly improves
stop_machine performance on s390 in overcommitted scenarios.
This includes common code changes which have been Acked by Peter
Zijlstra and Thomas Gleixner.
- Improve jump label transformation speed: transform jump labels
without using stop_machine.
- Refactoring of the vfio-ccw cp handling, simplifying the code and
avoiding unneeded allocating/copying.
- Various vfio-ccw fixes (ccw translation, state machine).
- Add support for vfio-ap queue interrupt control in the guest. This
includes s390 kvm changes which have been Acked by Christian
Borntraeger.
- Add protected virtualization support for virtio-ccw.
- Enforce both CONFIG_SMP and CONFIG_HOTPLUG_CPU, which allows to
remove some code which most likely isn't working at all, besides that
s390 didn't even compile for !CONFIG_SMP.
- Support for special flagged EP11 CPRBs for zcrypt.
- Handle PCI devices with no support for new MIO instructions.
- Avoid KASAN false positives in reworked stack unwinder.
- Couple of fixes for the QDIO layer.
- Convert s390 specific documentation to ReST format.
- Let s390 crypto modules return -ENODEV instead of -EOPNOTSUPP if
hardware is missing. This way our modules behave like most other
modules and which is also what systemd's systemd-modules-load.service
expects.
- Replace defconfig with performance_defconfig, so there is one config
file less to maintain.
- Remove the SCLP call home device driver, which was never useful.
- Cleanups all over the place.
* tag 's390-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (83 commits)
docs: s390: s390dbf: typos and formatting, update crash command
docs: s390: unify and update s390dbf kdocs at debug.c
docs: s390: restore important non-kdoc parts of s390dbf.rst
vfio-ccw: Fix the conversion of Format-0 CCWs to Format-1
s390/pci: correctly handle MIO opt-out
s390/pci: deal with devices that have no support for MIO instructions
s390: ap: kvm: Enable PQAP/AQIC facility for the guest
s390: ap: implement PAPQ AQIC interception in kernel
vfio: ap: register IOMMU VFIO notifier
s390: ap: kvm: add PQAP interception for AQIC
s390/unwind: cleanup unused READ_ONCE_TASK_STACK
s390/kasan: avoid false positives during stack unwind
s390/qdio: don't touch the dsci in tiqdio_add_input_queues()
s390/qdio: (re-)initialize tiqdio list entries
s390/dasd: Fix a precision vs width bug in dasd_feature_list()
s390/cio: introduce driver_override on the css bus
vfio-ccw: make convert_ccw0_to_ccw1 static
vfio-ccw: Remove copy_ccw_from_iova()
vfio-ccw: Factor out the ccw0-to-ccw1 transition
vfio-ccw: Copy CCW data outside length calculation
...
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Rather than allocating/freeing a piece of memory every time
we try to figure out how long a CCW chain is, let's use a piece
of memory allocated for each device.
The io_mutex added with commit 4f76617378ee9 ("vfio-ccw: protect
the I/O region") is held for the duration of the VFIO_CCW_EVENT_IO_REQ
event that accesses/uses this space, so there should be no race
concerns with another CPU attempting an (unexpected) SSCH for the
same device.
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-2-farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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Free the vfio_ccw_cmd_region on module exit.
Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions")
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Message-Id: <c0f39039d28af39ea2939391bf005e3495d890fd.1559576250.git.alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Otherwise, the guest can believe it's okay to start another I/O
and bump into the non-idle state. This results in a cc=2 (with
the asynchronous CSCH/HSCH code) returned to the guest, which is
unfortunate since everything is otherwise working normally.
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Message-Id: <20190514234248.36203-3-farman@linux.ibm.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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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Farhan Ali
Linus Torvalds
Eric Farman
Cornelia Huck
Pierre Morel
Sebastian Ott
Dong Jia Shi
Greg Kroah-Hartman
Sebastian Ott