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Sean Christopherson f01c5f1ae9 KVM: nVMX: Emulate NOPs in L2, and PAUSE if it's not intercepted
commit 4984563823 upstream.

Extend VMX's nested intercept logic for emulated instructions to handle
"pause" interception, in quotes because KVM's emulator doesn't filter out
NOPs when checking for nested intercepts.  Failure to allow emulation of
NOPs results in KVM injecting a #UD into L2 on any NOP that collides with
the emulator's definition of PAUSE, i.e. on all single-byte NOPs.

For PAUSE itself, honor L1's PAUSE-exiting control, but ignore PLE to
avoid unnecessarily injecting a #UD into L2.  Per the SDM, the first
execution of PAUSE after VM-Entry is treated as the beginning of a new
loop, i.e. will never trigger a PLE VM-Exit, and so L1 can't expect any
given execution of PAUSE to deterministically exit.

  ... the processor considers this execution to be the first execution of
  PAUSE in a loop. (It also does so for the first execution of PAUSE at
  CPL 0 after VM entry.)

All that said, the PLE side of things is currently a moot point, as KVM
doesn't expose PLE to L1.

Note, vmx_check_intercept() is still wildly broken when L1 wants to
intercept an instruction, as KVM injects a #UD instead of synthesizing a
nested VM-Exit.  That issue extends far beyond NOP/PAUSE and needs far
more effort to fix, i.e. is a problem for the future.

Fixes: 07721feee4 ("KVM: nVMX: Don't emulate instructions in guest mode")
Cc: Mathias Krause <minipli@grsecurity.net>
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20230405002359.418138-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2023-05-11 23:03:03 +09:00
arch KVM: nVMX: Emulate NOPs in L2, and PAUSE if it's not intercepted 2023-05-11 23:03:03 +09:00
block blk-crypto: make blk_crypto_evict_key() more robust 2023-05-11 23:03:01 +09:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: api - Demote BUG_ON() in crypto_unregister_alg() to a WARN_ON() 2023-05-11 23:03:02 +09:00
Documentation blk-crypto: don't use struct request_queue for public interfaces 2023-05-11 23:03:00 +09:00
drivers crypto: ccp - Don't initialize CCP for PSP 0x1649 2023-05-11 23:03:02 +09:00
fs reiserfs: Add security prefix to xattr name in reiserfs_security_write() 2023-05-11 23:03:02 +09:00
include tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem 2023-05-11 23:03:01 +09:00
init gcc: disable '-Warray-bounds' for gcc-13 too 2023-04-26 14:28:43 +02:00
io_uring io_uring: fix memory leak when removing provided buffers 2023-04-13 16:55:31 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed 2023-05-11 23:03:02 +09:00
lib maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug 2023-04-26 14:28:39 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/mempolicy: fix use-after-free of VMA iterator 2023-05-01 08:26:27 +09:00
net bluetooth: Perform careful capability checks in hci_sock_ioctl() 2023-05-01 08:26:27 +09:00
rust rust: kernel: Mark rust_fmt_argument as extern "C" 2023-04-26 14:28:38 +02:00
samples ftrace: Export ftrace_free_filter() to modules 2023-02-01 08:34:37 +01:00
scripts ASN.1: Fix check for strdup() success 2023-04-26 14:28:44 +02:00
security IMA: allow/fix UML builds 2023-05-11 23:02:59 +09:00
sound ASoC: amd: ps: update the acp clock source. 2023-05-11 23:02:59 +09:00
tools selftests mount: Fix mount_setattr_test builds failed 2023-05-11 23:02:58 +09:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:34:11 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS audit: update the mailing list in MAINTAINERS 2023-02-25 11:25:42 +01:00
Makefile Linux 6.1.27 2023-05-01 08:26:28 +09:00
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.