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Sean Christopherson a18bdaca46 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 23:00:18 +09:00
arch KVM: nVMX: Emulate NOPs in L2, and PAUSE if it's not intercepted 2023-05-11 23:00:18 +09:00
block blk-crypto: make blk_crypto_evict_key() more robust 2023-05-11 23:00:16 +09:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: api - Demote BUG_ON() in crypto_unregister_alg() to a WARN_ON() 2023-05-11 23:00:17 +09:00
Documentation riscv: Move early dtb mapping into the fixmap region 2023-05-01 08:23:24 +09:00
drivers crypto: safexcel - Cleanup ring IRQ workqueues on load failure 2023-05-11 23:00:17 +09:00
fs reiserfs: Add security prefix to xattr name in reiserfs_security_write() 2023-05-11 23:00:17 +09:00
include tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystem 2023-05-11 23:00:16 +09:00
init kbuild: Add CONFIG_PAHOLE_VERSION 2023-02-25 12:06:45 +01:00
io_uring io_uring: avoid null-ptr-deref in io_arm_poll_handler 2023-03-22 13:31:37 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel rcu: Avoid stack overflow due to __rcu_irq_enter_check_tick() being kprobe-ed 2023-05-11 23:00:17 +09:00
lib kobject: Fix slab-out-of-bounds in fill_kobj_path() 2023-03-10 09:39:35 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/page_alloc: fix potential deadlock on zonelist_update_seq seqlock 2023-04-26 13:51:55 +02:00
net bluetooth: Perform careful capability checks in hci_sock_ioctl() 2023-05-01 08:23:23 +09:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2022-12-31 13:14:31 +01:00
scripts ASN.1: Fix check for strdup() success 2023-04-26 13:51:56 +02:00
security IMA: allow/fix UML builds 2023-05-11 23:00:16 +09:00
sound ASoC: Intel: bytcr_rt5640: Add quirk for the Acer Iconia One 7 B1-750 2023-05-11 23:00:15 +09:00
tools selftests mount: Fix mount_setattr_test builds failed 2023-05-11 23:00:15 +09:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: fix memoryleak in kvm_init() 2023-03-17 08:49:04 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +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: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 counter: Internalize sysfs interface code 2023-04-20 12:13:55 +02:00
Makefile Linux 5.15.110 2023-05-01 08:23:24 +09:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.