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Filename Latest commit message Latest commit date
Sean Christopherson fac026dac0 KVM: x86/mmu: Treat invalid shadow pages as obsolete
Treat invalid shadow pages as obsolete to fix a bug where an obsolete
and invalid page with a non-zero root count could become non-obsolete
due to mmu_valid_gen wrapping.  The bug is largely theoretical with the
current code base, as an unsigned long will effectively never wrap on
64-bit KVM, and userspace would have to deliberately stall a vCPU in
order to keep an obsolete invalid page on the active list while
simultaneously modifying memslots billions of times to trigger a wrap.

The obvious alternative is to use a 64-bit value for mmu_valid_gen,
but it's actually desirable to go in the opposite direction, i.e. using
a smaller 8-bit value to reduce KVM's memory footprint by 8 bytes per
shadow page, and relying on proper treatment of invalid pages instead of
preventing the generation from wrapping.

Note, "Fixes" points at a commit that was at one point reverted, but has
since been restored.

Fixes: 5304b8d37c ("KVM: MMU: fast invalidate all pages")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-09-24 14:35:12 +02:00
arch KVM: x86/mmu: Treat invalid shadow pages as obsolete 2019-09-24 14:35:12 +02:00
block
certs
crypto
Documentation KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH 2019-09-24 13:37:13 +02:00
drivers - New Drivers 2019-09-23 19:37:49 -07:00
fs selinux/stable-5.4 PR 20190917 2019-09-23 11:21:04 -07:00
include cpu/SMT: create and export cpu_smt_possible() 2019-09-24 13:37:28 +02:00
init Modules updates for v5.4 2019-09-22 10:34:46 -07:00
ipc
kernel cpu/SMT: create and export cpu_smt_possible() 2019-09-24 13:37:28 +02:00
lib Modules updates for v5.4 2019-09-22 10:34:46 -07:00
LICENSES
mm
net
samples rpmsg updates for v5.4 2019-09-22 10:58:15 -07:00
scripts Modules updates for v5.4 2019-09-22 10:34:46 -07:00
security I have four patches for v5.4. Nothing is major. All but one are in 2019-09-23 14:25:45 -07:00
sound
tools KVM: selftests: hyperv_cpuid: add check for NoNonArchitecturalCoreSharing bit 2019-09-24 13:37:31 +02:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS - New Drivers 2019-09-23 19:37:49 -07:00
Makefile Modules updates for v5.4 2019-09-22 10:34:46 -07:00
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.