The source for the Linux kernel used in Windows Subsystem for Linux 2 (WSL2)
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Paul Mackerras ae49dedaa9 KVM: PPC: Book3S HV: Handle non-present PTEs in page fault functions
Since cd758a9b57 "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT
page fault handler", it's been possible in fairly rare circumstances to
load a non-present PTE in kvmppc_book3s_hv_page_fault() when running a
guest on a POWER8 host.

Because that case wasn't checked for, we could misinterpret the non-present
PTE as being a cache-inhibited PTE.  That could mismatch with the
corresponding hash PTE, which would cause the function to fail with -EFAULT
a little further down.  That would propagate up to the KVM_RUN ioctl()
generally causing the KVM userspace (usually qemu) to fall over.

This addresses the problem by catching that case and returning to the guest
instead.

For completeness, this fixes the radix page fault handler in the same
way.  For radix this didn't cause any obvious misbehaviour, because we
ended up putting the non-present PTE into the guest's partition-scoped
page tables, leading immediately to another hypervisor data/instruction
storage interrupt, which would go through the page fault path again
and fix things up.

Fixes: cd758a9b57 "KVM: PPC: Book3S HV: Use __gfn_to_pfn_memslot in HPT page fault handler"
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1820402
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2020-04-21 09:23:41 +10:00
Documentation ARM: 2020-04-02 15:13:15 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch KVM: PPC: Book3S HV: Handle non-present PTEs in page fault functions 2020-04-21 09:23:41 +10:00
block Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2020-04-01 14:52:59 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-04-01 14:47:40 -07:00
drivers Merge branch 'akpm' (patches from Andrew) 2020-04-02 13:55:34 -07:00
fs Merge branch 'akpm' (patches from Andrew) 2020-04-02 13:55:34 -07:00
include ARM: 2020-04-02 15:13:15 -07:00
init Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-04-02 11:22:17 -07:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel Merge branch 'akpm' (patches from Andrew) 2020-04-02 13:55:34 -07:00
lib Merge branch 'akpm' (patches from Andrew) 2020-04-02 13:55:34 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2020-04-02 13:55:34 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-03-31 17:29:33 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-03-31 17:29:33 -07:00
scripts scripts/spelling.txt: add more spellings to spelling.txt 2020-04-02 09:35:25 -07:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-04-02 14:49:46 -07:00
sound Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-03-31 17:29:33 -07:00
tools ARM: 2020-04-02 15:13:15 -07:00
usr initramfs: restore default compression behavior 2020-03-17 09:50:37 +09:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 selftest/lkdtm: Use local .gitignore 2020-03-02 08:39:39 -07:00
.mailmap media updates for v5.7-rc1 2020-03-30 13:42:05 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS ARM: 2020-04-02 15:13:15 -07:00
Makefile Kbuild updates for v5.7 2020-03-31 16:03:39 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.