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Lai Jiangshan 6e1d849fa3 KVM: x86: Intercept LA57 to inject #GP fault when it's reserved
Unconditionally intercept changes to CR4.LA57 so that KVM correctly
injects a #GP fault if the guest attempts to set CR4.LA57 when it's
supported in hardware but not exposed to the guest.

Long term, KVM needs to properly handle CR4 bits that can be under guest
control but also may be reserved from the guest's perspective.  But, KVM
currently sets the CR4 guest/host mask only during vCPU creation, and
reworking flows to change that will take a bit of elbow grease.

Even if/when generic support for intercepting reserved bits exists, it's
probably not worth letting the guest set CR4.LA57 directly.  LA57 can't
be toggled while long mode is enabled, thus it's all but guaranteed to
be set once (maybe twice, e.g. by BIOS and kernel) during boot and never
touched again.  On the flip side, letting the guest own CR4.LA57 may
incur extra VMREADs.  In other words, this temporary "hack" is probably
also the right long term fix.

Fixes: fd8cb43373 ("KVM: MMU: Expose the LA57 feature to VM.")
Cc: stable@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
[sean: rewrote changelog]
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200930041659.28181-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-10-21 17:48:49 -04:00
arch KVM: x86: Intercept LA57 to inject #GP fault when it's reserved 2020-10-21 17:48:49 -04:00
block block-5.9-2020-09-04 2020-09-04 13:04:51 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation Documentation: kvm: fix some typos in cpuid.rst 2020-10-21 17:36:32 -04:00
drivers IOMMU Fixes for Linux v5.9-rc3 2020-09-06 11:58:15 -07:00
fs io_uring-5.9-2020-09-06 2020-09-06 12:10:27 -07:00
include kvm: x86: only provide PV features if enabled in guest's CPUID 2020-10-21 17:36:32 -04:00
init init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Misc fixes: 2020-09-06 10:28:00 -07:00
lib lib: Revert use of fallthrough pseudo-keyword in lib/ 2020-08-24 14:17:44 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm xen: branch for v5.9-rc4 2020-09-06 09:59:27 -07:00
net net/packet: fix overflow in tpacket_rcv 2020-09-04 11:56:02 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts Merge branch 'akpm' (patches from Andrew) 2020-09-05 13:28:40 -07:00
security treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools KVM: x86: do not attempt TSC synchronization on guest writes 2020-09-28 07:59:52 -04:00
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: use struct_size() and flex_array_size() helpers in kvm_io_bus_unregister_dev() 2020-09-28 07:57:17 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.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 .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
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 IOMMU Fixes for Linux v5.9-rc3 2020-09-06 11:58:15 -07:00
Makefile Linux 5.9-rc4 2020-09-06 17:11:40 -07:00
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.