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Filename Latest commit message Latest commit date
Sean Christopherson db209f39f1 KVM: x86: Fail emulation during EMULTYPE_SKIP on any exception
[ Upstream commit 17122c06b86c9f77f45b86b8e62c3ed440847a59 ]

Treat any exception during instruction decode for EMULTYPE_SKIP as a
"full" emulation failure, i.e. signal failure instead of queuing the
exception.  When decoding purely to skip an instruction, KVM and/or the
CPU has already done some amount of emulation that cannot be unwound,
e.g. on an EPT misconfig VM-Exit KVM has already processeed the emulated
MMIO.  KVM already does this if a #UD is encountered, but not for other
exceptions, e.g. if a #PF is encountered during fetch.

In SVM's soft-injection use case, queueing the exception is particularly
problematic as queueing exceptions while injecting events can put KVM
into an infinite loop due to bailing from VM-Enter to service the newly
pending exception.  E.g. multiple warnings to detect such behavior fire:

  ------------[ cut here ]------------
  WARNING: CPU: 3 PID: 1017 at arch/x86/kvm/x86.c:9873 kvm_arch_vcpu_ioctl_run+0x1de5/0x20a0 [kvm]
  Modules linked in: kvm_amd ccp kvm irqbypass
  CPU: 3 PID: 1017 Comm: svm_nested_soft Not tainted 6.0.0-rc1+ #220
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:kvm_arch_vcpu_ioctl_run+0x1de5/0x20a0 [kvm]
  Call Trace:
   kvm_vcpu_ioctl+0x223/0x6d0 [kvm]
   __x64_sys_ioctl+0x85/0xc0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
  ---[ end trace 0000000000000000 ]---
  ------------[ cut here ]------------
  WARNING: CPU: 3 PID: 1017 at arch/x86/kvm/x86.c:9987 kvm_arch_vcpu_ioctl_run+0x12a3/0x20a0 [kvm]
  Modules linked in: kvm_amd ccp kvm irqbypass
  CPU: 3 PID: 1017 Comm: svm_nested_soft Tainted: G        W          6.0.0-rc1+ #220
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:kvm_arch_vcpu_ioctl_run+0x12a3/0x20a0 [kvm]
  Call Trace:
   kvm_vcpu_ioctl+0x223/0x6d0 [kvm]
   __x64_sys_ioctl+0x85/0xc0
   do_syscall_64+0x2b/0x50
   entry_SYSCALL_64_after_hwframe+0x46/0xb0
  ---[ end trace 0000000000000000 ]---

Fixes: 6ea6e84309 ("KVM: x86: inject exceptions produced by x86_decode_insn")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220930233632.1725475-1-seanjc@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-25 11:53:26 +01:00
arch KVM: x86: Fail emulation during EMULTYPE_SKIP on any exception 2023-02-25 11:53:26 +01:00
block blk-cgroup: fix missing pd_online_fn() while activating policy 2023-02-06 07:52:48 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation docs: Fix path paste-o for /sys/kernel/warn_count 2023-02-06 07:52:50 +01:00
drivers wifi: rtl8xxxu: gen2: Turn on the rate control 2023-02-25 11:53:25 +01:00
fs nilfs2: fix underflow in second superblock position calculations 2023-02-22 12:50:41 +01:00
include random: always mix cycle counter in add_latent_entropy() 2023-02-25 11:53:25 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel sched/psi: Fix use-after-free in ep_remove_wait_queue() 2023-02-22 12:50:39 +01:00
lib netlink: prevent potential spectre v1 gadgets 2023-02-06 07:52:45 +01:00
LICENSES
mm Revert "mm: Always release pages to the buddy allocator in memblock_free_late()." 2023-02-22 12:50:39 +01:00
net net: sched: sch: Fix off by one in htb_activate_prios() 2023-02-22 12:50:42 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts ftrace/scripts: Update the instructions for ftrace-bisect.sh 2023-02-06 07:52:44 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-06 07:52:35 +01:00
sound ASoC: SOF: Intel: hda-dai: fix possible stream_tag leak 2023-02-22 12:50:42 +01:00
tools Revert "ipv4: Fix incorrect route flushing when source address is deleted" 2023-02-22 12:50:38 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS net/phy/mdio-i2c: Move header file to include/linux/mdio 2023-02-06 07:52:46 +01:00
Makefile Linux 5.4.232 2023-02-22 12:50:42 +01:00
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.