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Claudio Imbrenda 63c71e83d5 KVM: s390: pv: leak the topmost page table when destroy fails
[ Upstream commit faa2f72cb3 ]

Each secure guest must have a unique ASCE (address space control
element); we must avoid that new guests use the same page for their
ASCE, to avoid errors.

Since the ASCE mostly consists of the address of the topmost page table
(plus some flags), we must not return that memory to the pool unless
the ASCE is no longer in use.

Only a successful Destroy Secure Configuration UVC will make the ASCE
reusable again.

If the Destroy Configuration UVC fails, the ASCE cannot be reused for a
secure guest (either for the ASCE or for other memory areas). To avoid
a collision, it must not be used again. This is a permanent error and
the page becomes in practice unusable, so we set it aside and leak it.
On failure we already leak other memory that belongs to the ultravisor
(i.e. the variable and base storage for a guest) and not leaking the
topmost page table was an oversight.

This error (and thus the leakage) should not happen unless the hardware
is broken or KVM has some unknown serious bug.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: 29b40f105e ("KVM: s390: protvirt: Add initial vm and cpu lifecycle handling")
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20220628135619.32410-2-imbrenda@linux.ibm.com
Message-Id: <20220628135619.32410-2-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2022-08-17 15:15:31 +02:00
arch KVM: s390: pv: leak the topmost page table when destroy fails 2022-08-17 15:15:31 +02:00
block blk-mq: don't create hctx debugfs dir until q->debugfs_dir is created 2022-08-17 15:14:16 +02:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation dt-bindings: mmc: sdhci-msm: Fix issues in yaml bindings 2022-08-17 15:15:30 +02:00
drivers mmc: block: Add single read for 4k sector cards 2022-08-17 15:15:31 +02:00
fs kernfs: fix potential NULL dereference in __kernfs_remove 2022-08-17 15:15:26 +02:00
include soundwire: revisit driver bind/unbind and callbacks 2022-08-17 15:15:28 +02:00
init stack: Declare {randomize_,}kstack_offset to fix Sparse warnings 2022-08-17 15:14:14 +02:00
io_uring io_uring: Don't require reinitable percpu_ref 2022-08-17 15:14:20 +02:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel wireguard: ratelimiter: use hrtimer in selftest 2022-08-17 15:14:59 +02:00
lib lib/test_hmm: avoid accessing uninitialized pages 2022-08-17 15:15:20 +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 get_nodes out of bound access 2022-08-17 15:15:26 +02:00
net dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock 2022-08-17 15:14:59 +02:00
samples sample: bpf: xdp_router_ipv4: Allow the kernel to send arp requests 2022-08-17 15:14:25 +02:00
scripts scripts/gdb: Fix gdb 'lx-symbols' command 2022-07-21 10:40:55 -07:00
security selinux: Add boundary check in put_entry() 2022-08-17 15:14:06 +02:00
sound devcoredump: remove the useless gfp_t parameter in dev_coredumpv and dev_coredumpm 2022-08-17 15:15:21 +02:00
tools rtla/utils: Use calloc and check the potential memory allocation failure 2022-08-17 15:15:30 +02:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: Don't set Accessed/Dirty bits for ZERO_PAGE 2022-08-17 15:15:21 +02:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +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 kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
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 io_uring: move to separate directory 2022-08-17 15:14:20 +02:00
Makefile io_uring: move to separate directory 2022-08-17 15:14:20 +02:00
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.