WSL2-Linux-Kernel

The source for the Linux kernel used in Windows Subsystem for Linux 2 (WSL2)

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Paolo Bonzini e3cdaab5ff KVM: x86: SVM: fix nested PAUSE filtering when L0 intercepts PAUSE Commit `74fd41ed16` ("KVM: x86: nSVM: support PAUSE filtering when L0 doesn't intercept PAUSE") introduced passthrough support for nested pause filtering, (when the host doesn't intercept PAUSE) (either disabled with kvm module param, or disabled with '-overcommit cpu-pm=on') Before this commit, L1 KVM didn't intercept PAUSE at all; afterwards, the feature was exposed as supported by KVM cpuid unconditionally, thus if L1 could try to use it even when the L0 KVM can't really support it. In this case the fallback caused KVM to intercept each PAUSE instruction; in some cases, such intercept can slow down the nested guest so much that it can fail to boot. Instead, before the problematic commit KVM was already setting both thresholds to 0 in vmcb02, but after the first userspace VM exit shrink_ple_window was called and would reset the pause_filter_count to the default value. To fix this, change the fallback strategy - ignore the guest threshold values, but use/update the host threshold values unless the guest specifically requests disabling PAUSE filtering (either simple or advanced). Also fix a minor bug: on nested VM exit, when PAUSE filter counter were copied back to vmcb01, a dirty bit was not set. Thanks a lot to Suravee Suthikulpanit for debugging this! Fixes: `74fd41ed16` ("KVM: x86: nSVM: support PAUSE filtering when L0 doesn't intercept PAUSE") Reported-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20220518072709.730031-1-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2022-06-09 10:52:21 -04:00
Documentation	KVM: arm64: Ignore 'kvm-arm.mode=protected' when using VHE	2022-06-09 13:24:02 +01:00
LICENSES	…
arch	KVM: x86: SVM: fix nested PAUSE filtering when L0 intercepts PAUSE	2022-06-09 10:52:21 -04:00
block	…
certs	…
crypto	…
drivers	…
fs	…
include	…
init	…
ipc	…
kernel	KVM/riscv fixes for 5.19, take #1	2022-06-09 09:45:00 -04:00
lib	…
mm	…
net	…
samples	…
scripts	…
security	…
sound	…
tools	KVM/riscv fixes for 5.19, take #1	2022-06-09 09:45:00 -04:00
usr	…
virt	KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un\|}blocking	2022-06-09 10:52:20 -04:00
.clang-format	…
.cocciconfig	…
.get_maintainer.ignore	…
.gitattributes	…
.gitignore	…
.mailmap	…
COPYING	…
CREDITS	…
Kbuild	…
Kconfig	…
MAINTAINERS	…
Makefile	…
README	…

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.