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Filename Latest commit message Latest commit date
Nicholas Piggin 5c895828f4 KVM: PPC: Book3S HV: Prevent POWER7/8 TLB flush flushing SLB
commit cf0b0e3712f7af90006f8317ff27278094c2c128 upstream.

The POWER9 ERAT flush instruction is a SLBIA with IH=7, which is a
reserved value on POWER7/8. On POWER8 this invalidates the SLB entries
above index 0, similarly to SLBIA IH=0.

If the SLB entries are invalidated, and then the guest is bypassed, the
host SLB does not get re-loaded, so the bolted entries above 0 will be
lost. This can result in kernel stack access causing a SLB fault.

Kernel stack access causing a SLB fault was responsible for the infamous
mega bug (search "Fix SLB reload bug"). Although since commit
48e7b76957 ("powerpc/64s/hash: Convert SLB miss handlers to C") that
starts using the kernel stack in the SLB miss handler, it might only
result in an infinite loop of SLB faults. In any case it's a bug.

Fix this by only executing the instruction on >= POWER9 where IH=7 is
defined not to invalidate the SLB. POWER7/8 don't require this ERAT
flush.

Fixes: 5008711259 ("KVM: PPC: Book3S HV: Invalidate ERAT when flushing guest TLB entries")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211119031627.577853-1-npiggin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-01 09:23:28 +01:00
arch KVM: PPC: Book3S HV: Prevent POWER7/8 TLB flush flushing SLB 2021-12-01 09:23:28 +01:00
block block: remove inaccurate requeue check 2021-11-17 09:48:31 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation xen/balloon: add late_initcall_sync() for initial ballooning done 2021-11-17 09:48:25 +01:00
drivers xen: detect uninitialized xenbus in xenbus_init 2021-12-01 09:23:28 +01:00
fs btrfs: fix memory ordering between normal and ordered work functions 2021-11-26 10:47:21 +01:00
include ALSA: hda: hdac_ext_stream: fix potential locking issues 2021-11-26 10:47:23 +01:00
init
ipc ipc: WARN if trying to remove ipc object which is absent 2021-11-26 10:47:21 +01:00
kernel perf/core: Avoid put_page() when GUP fails 2021-11-26 10:47:22 +01:00
lib lib/xz: Validate the value before assigning it to an enum variable 2021-11-17 09:48:31 +01:00
LICENSES
mm hugetlbfs: flush TLBs correctly after huge_pmd_unshare 2021-11-26 10:47:23 +01:00
net net: nexthop: fix null pointer dereference when IPv6 is not enabled 2021-12-01 09:23:27 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts leaking_addresses: Always print a trailing newline 2021-11-17 09:48:31 +01:00
security fortify: Explicitly disable Clang support 2021-11-21 13:38:50 +01:00
sound ALSA: ctxfi: Fix out-of-range access 2021-12-01 09:23:28 +01:00
tools perf tests: Remove bash construct from record+zstd_comp_decomp.sh 2021-11-26 10:47:18 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.162 2021-11-26 10:47:23 +01:00
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.