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James Morse 5dcd0fdbb4 KVM: arm64: Defer guest entry when an asynchronous exception is pending
SError that occur during world-switch's entry to the guest will be
accounted to the guest, as the exception is masked until we enter the
guest... but we want to attribute the SError as precisely as possible.

Reading DISR_EL1 before guest entry requires free registers, and using
ESB+DISR_EL1 to consume and read back the ESR would leave KVM holding
a host SError... We would rather leave the SError pending and let the
host take it once we exit world-switch. To do this, we need to defer
guest-entry if an SError is pending.

Read the ISR to see if SError (or an IRQ) is pending. If so fake an
exit. Place this check between __guest_enter()'s save of the host
registers, and restore of the guest's. SError that occur between
here and the eret into the guest must have affected the guest's
registers, which we can naturally attribute to the guest.

The dsb is needed to ensure any previous writes have been done before
we read ISR_EL1. On systems without the v8.2 RAS extensions this
doesn't give us anything as we can't contain errors, and the ESR bits
to describe the severity are all implementation-defined. Replace
this with a nop for these systems.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-07-05 13:03:30 +01:00
arch KVM: arm64: Defer guest entry when an asynchronous exception is pending 2019-07-05 13:03:30 +01:00
block block: fix page leak when merging to same page 2019-06-17 09:33:04 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
Documentation Char/Misc driver fixes for 5.2-rc6 2019-06-21 10:18:16 -07:00
drivers IOMMU Fix for v5.2-rc5: 2019-06-22 14:08:47 -07:00
fs More NFS client fixes for Linux 5.2 2019-06-21 13:45:41 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-21 22:23:35 -07:00
init Char/Misc driver fixes for 5.2-rc4 2019-06-08 12:50:36 -07:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
lib SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
net Bluetooth: Fix regression with minimum encryption key size alignment 2019-06-22 09:07:39 -07:00
samples SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
scripts treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
security SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tools SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
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.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap MAINTAINERS: Update my email address 2019-06-18 14:37:27 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Char/Misc driver fixes for 5.2-rc6 2019-06-21 10:18:16 -07:00
Makefile Linux 5.2-rc6 2019-06-22 16:01:36 -07:00
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.