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Filename Latest commit message Latest commit date
Eric Farman 575ad4ab20 vfio-ccw: Serialize FSM IDLE state with I/O completion
[ Upstream commit 2af7a834a435460d546f0cf0a8b8e4d259f1d910 ]

Today, the stacked call to vfio_ccw_sch_io_todo() does three things:

  1) Update a solicited IRB with CP information, and release the CP
     if the interrupt was the end of a START operation.
  2) Copy the IRB data into the io_region, under the protection of
     the io_mutex
  3) Reset the vfio-ccw FSM state to IDLE to acknowledge that
     vfio-ccw can accept more work.

The trouble is that step 3 is (A) invoked for both solicited and
unsolicited interrupts, and (B) sitting after the mutex for step 2.
This second piece becomes a problem if it processes an interrupt
for a CLEAR SUBCHANNEL while another thread initiates a START,
thus allowing the CP and FSM states to get out of sync. That is:

    CPU 1                           CPU 2
    fsm_do_clear()
    fsm_irq()
                                    fsm_io_request()
    vfio_ccw_sch_io_todo()
                                    fsm_io_helper()

Since the FSM state and CP should be kept in sync, let's make a
note when the CP is released, and rely on that as an indication
that the FSM should also be reset at the end of this routine and
open up the device for more work.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Acked-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20210511195631.3995081-4-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-16 11:59:33 +02:00
arch x86/kvm: Disable all PV features on crash 2021-06-10 13:37:16 +02:00
block blk-mq: Swap two calls in blk_mq_exit_queue() 2021-05-19 10:08:30 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation XArray: add xas_split 2021-06-10 13:37:14 +02:00
drivers vfio-ccw: Serialize FSM IDLE state with I/O completion 2021-06-16 11:59:33 +02:00
fs proc: Track /proc/$pid/attr/ opener mm_struct 2021-06-16 11:59:32 +02:00
include XArray: add xas_split 2021-06-10 13:37:14 +02:00
init pid: take a reference when initializing cad_pid 2021-06-10 13:37:11 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel bpf: No need to simulate speculative domain for immediates 2021-05-28 13:10:26 +02:00
lib lib/lz4: explicitly support in-place decompression 2021-06-10 13:37:16 +02:00
LICENSES
mm mm/filemap: fix storing to a THP shadow entry 2021-06-10 13:37:15 +02:00
net net/nfc/rawsock.c: fix a permission check bug 2021-06-16 11:59:33 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts scripts: switch explicitly to Python 3 2021-05-22 11:38:30 +02:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ASoC: Intel: bytcr_rt5640: Add quirk for the Lenovo Miix 3-830 tablet 2021-06-16 11:59:33 +02:00
tools perf jevents: Fix getting maximum number of fds 2021-06-03 08:59:08 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Initialize VCPU mdcr_el2 before loading it 2021-05-22 11:38:30 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.125 2021-06-10 13:37:17 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.