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Nicholas Piggin cf0b0e3712 KVM: PPC: Book3S HV: Prevent POWER7/8 TLB flush flushing SLB
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
2021-11-24 21:00:36 +11:00
arch KVM: PPC: Book3S HV: Prevent POWER7/8 TLB flush flushing SLB 2021-11-24 21:00:36 +11:00
block blk-mq: don't insert FUA request with data into scheduler queue 2021-11-19 06:28:18 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
Documentation Power management fixes for 5.16-rc2 2021-11-18 14:46:28 -08:00
drivers Pin control fixes for the v5.16 kernel series: 2021-11-20 10:59:03 -08:00
fs pstore/blk: Use "%lu" to format unsigned long 2021-11-21 09:44:19 -08:00
include Merge branch 'akpm' (patches from Andrew) 2021-11-20 13:17:24 -08:00
init kbuild: Fix -Wimplicit-fallthrough=5 error for GCC 5.x and 6.x 2021-11-14 18:59:49 -08:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-11-20 10:35:54 -08:00
kernel Tracing fixes: 2021-11-19 13:50:48 -08:00
lib kasan: test: silence intentional read overflow warnings 2021-11-20 10:35:54 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm kmap_local: don't assume kmap PTEs are linear arrays in memory 2021-11-20 10:35:54 -08:00
net Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
samples s390 updates for 5.16-rc2 2021-11-20 10:55:50 -08:00
scripts coccinelle patches for 5.16-rc1 2021-11-13 10:45:17 -08:00
security net,lsm,selinux: revert the security_sctp_assoc_established() hook 2021-11-14 12:21:53 +00:00
sound sound fixes for 5.16-rc1 2021-11-12 12:17:30 -08:00
tools perf tools fixes for 5.16: 1st batch 2021-11-19 12:47:29 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt Merge branch 'kvm-5.16-fixes' into kvm-master 2021-11-18 02:11:57 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap MAINTAINERS: update email address of Christian Borntraeger 2021-11-18 17:50:54 +01:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS s390 updates for 5.16-rc2 2021-11-20 10:55:50 -08:00
Makefile Linux 5.16-rc2 2021-11-21 13:47:39 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.