mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity
1,150,271 Commits 103 Branches 5,016 Tags 5.4 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
Go to file
Tao Su 43cea54109 KVM: x86: Clear bit12 of ICR after APIC-write VM-exit 
commit 629d3698f6 upstream.

When IPI virtualization is enabled, a WARN is triggered if bit12 of ICR
MSR is set after APIC-write VM-exit. The reason is kvm_apic_send_ipi()
thinks the APIC_ICR_BUSY bit should be cleared because KVM has no delay,
but kvm_apic_write_nodecode() doesn't clear the APIC_ICR_BUSY bit.

Under the x2APIC section, regarding ICR, the SDM says:

  It remains readable only to aid in debugging; however, software should
  not assume the value returned by reading the ICR is the last written
  value.

I.e. the guest is allowed to set bit 12.  However, the SDM also gives KVM
free reign to do whatever it wants with the bit, so long as KVM's behavior
doesn't confuse userspace or break KVM's ABI.

Clear bit 12 so that it reads back as '0'. This approach is safer than
"do nothing" and is consistent with the case where IPI virtualization is
disabled or not supported, i.e.,

  handle_fastpath_set_x2apic_icr_irqoff() -> kvm_x2apic_icr_write()

Opportunistically replace the TODO with a comment calling out that eating
the write is likely faster than a conditional branch around the busy bit.

Link: https://lore.kernel.org/all/ZPj6iF0Q7iynn62p@google.com/
Fixes: 5413bcba7e ("KVM: x86: Add support for vICR APIC-write VM-Exits in x2APIC mode")
Cc: stable@vger.kernel.org
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Link: https://lore.kernel.org/r/20230914055504.151365-1-tao1.su@linux.intel.com
[sean: tweak changelog, replace TODO with comment, drop local "val"]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2023-11-28 17:07:08 +00:00
Documentation smp,csd: Throw an error if a CSD lock is stuck for too long 2023-11-28 17:06:55 +00:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
arch KVM: x86: Clear bit12 of ICR after APIC-write VM-exit 2023-11-28 17:07:08 +00:00
block blk-core: use pr_warn_ratelimited() in bio_check_ro() 2023-11-20 11:52:17 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 17:06:58 +00:00
drivers scsi: qla2xxx: Fix system crash due to bad pointer access 2023-11-28 17:07:07 +00:00
fs cifs: fix check of rc in function generate_smb3signingkey 2023-11-28 17:07:07 +00:00
include netfilter: nf_tables: fix pointer math issue in nft_byteorder_eval() 2023-11-28 17:07:05 +00:00
init sched/psi: Select KERNFS as needed 2023-09-13 09:42:28 +02:00
io_uring io_uring/net: ensure socket is marked connected on connect retry 2023-11-20 11:52:18 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel bpf: Fix precision tracking for BPF_ALU | BPF_TO_BE | BPF_END 2023-11-28 17:07:07 +00:00
lib lib/generic-radix-tree.c: Don't overflow in peek() 2023-11-28 17:06:54 +00:00
mm filemap: add filemap_get_folios_tag() 2023-11-20 11:52:09 +01:00
net netfilter: nf_tables: fix pointer math issue in nft_byteorder_eval() 2023-11-28 17:07:05 +00:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples fprobe: Pass entry_data to handlers 2023-10-25 12:03:12 +02:00
scripts randstruct: Fix gcc-plugin performance mode to stay in group 2023-11-28 17:07:07 +00:00
security apparmor: fix invalid reference on profile->disconnected 2023-11-20 11:52:09 +01:00
sound ALSA: hda/realtek: Add quirk for ASUS UX7602ZM 2023-11-28 17:07:03 +00:00
tools perf intel-pt: Fix async branch flags 2023-11-28 17:07:07 +00:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add() 2023-09-13 09:42:46 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig
…
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes
…
.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 devlink: move code to a dedicated directory 2023-08-30 16:11:00 +02:00
Makefile Linux 6.1.63 2023-11-20 11:52:19 +01:00
README
…

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.