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Ben Gardon ed5e484b79 KVM: x86/mmu: Ensure forward progress when yielding in TDP MMU iter
In some functions the TDP iter risks not making forward progress if two
threads livelock yielding to one another. This is possible if two threads
are trying to execute wrprot_gfn_range. Each could write protect an entry
and then yield. This would reset the tdp_iter's walk over the paging
structure and the loop would end up repeating the same entry over and
over, preventing either thread from making forward progress.

Fix this issue by only yielding if the loop has made forward progress
since the last yield.

Fixes: a6a0b05da9 ("kvm: x86/mmu: Support dirty logging for the TDP MMU")
Reviewed-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>

Message-Id: <20210202185734.1680553-14-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04 05:27:40 -05:00
arch KVM: x86/mmu: Ensure forward progress when yielding in TDP MMU iter 2021-02-04 05:27:40 -05:00
block block-5.11-2021-01-10 2021-01-10 12:53:08 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Char/Misc driver fixes for 5.11-rc3 2021-01-10 12:24:33 -08:00
Documentation KVM: X86: Add the Document for KVM_CAP_X86_BUS_LOCK_EXIT 2021-02-04 05:27:22 -05:00
drivers KVM/SVM: add support for SEV attestation command 2021-02-04 05:27:20 -05:00
fs block-5.11-2021-01-10 2021-01-10 12:53:08 -08:00
include KVM: VMX: Enable bus lock VM exit 2021-02-04 05:27:21 -05:00
init Revert "init/console: Use ttynull as a fallback when there is no console" 2021-01-08 11:02:18 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel Staging driver fixes for 5.11-rc3 2021-01-10 12:28:07 -08:00
lib Kbuild fixes for v5.11 2021-01-10 13:24:55 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm: make wait_on_page_writeback() wait for multiple pending writebacks 2021-01-05 11:33:00 -08:00
net nexthop: Bounce NHA_GATEWAY in FDB nexthop groups 2021-01-07 18:47:18 -08:00
samples ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
scripts Kbuild fixes for v5.11 2021-01-10 13:24:55 -08:00
security Provide a fix for the incorrect handling of privilege 2020-12-24 14:08:43 -08:00
sound sound fixes for 5.11-rc3 2021-01-05 13:25:49 -08:00
tools selftest: kvm: x86: test KVM_GET_CPUID2 and guest visible CPUIDs against KVM_GET_SUPPORTED_CPUID 2021-02-04 05:27:36 -05:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: X86: use vzalloc() instead of vmalloc/memset 2021-02-04 05:27:15 -05:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.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: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-11 22:29:38 -08:00
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 Kbuild fixes for v5.11 2021-01-10 13:24:55 -08:00
Makefile Linux 5.11-rc3 2021-01-10 14:34:50 -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.