Revision 86f7e90ce840aa1db407d3ea6e9b3a52b2ce923c authored by Oliver Upton on 29 February 2020, 19:30:14 UTC, committed by Paolo Bonzini on 01 March 2020, 18:26:31 UTC
KVM emulates UMIP on hardware that doesn't support it by setting the
'descriptor table exiting' VM-execution control and performing
instruction emulation. When running nested, this emulation is broken as
KVM refuses to emulate L2 instructions by default.
Correct this regression by allowing the emulation of descriptor table
instructions if L1 hasn't requested 'descriptor table exiting'.
Fixes: 07721feee46b ("KVM: nVMX: Don't emulate instructions in guest mode")
Reported-by: Jan Kiszka <jan.kiszka@web.de>
Cc: stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent e951445
Kconfig.ubsan
# SPDX-License-Identifier: GPL-2.0-only
config ARCH_HAS_UBSAN_SANITIZE_ALL
bool
config UBSAN
bool "Undefined behaviour sanity checker"
help
This option enables undefined behaviour sanity checker
Compile-time instrumentation is used to detect various undefined
behaviours in runtime. Various types of checks may be enabled
via boot parameter ubsan_handle
(see: Documentation/dev-tools/ubsan.rst).
config UBSAN_SANITIZE_ALL
bool "Enable instrumentation for the entire kernel"
depends on UBSAN
depends on ARCH_HAS_UBSAN_SANITIZE_ALL
# We build with -Wno-maybe-uninitilzed, but we still want to
# use -Wmaybe-uninitilized in allmodconfig builds.
# So dependsy bellow used to disable this option in allmodconfig
depends on !COMPILE_TEST
default y
help
This option activates instrumentation for the entire kernel.
If you don't enable this option, you have to explicitly specify
UBSAN_SANITIZE := y for the files/directories you want to check for UB.
Enabling this option will get kernel image size increased
significantly.
config UBSAN_NO_ALIGNMENT
bool "Disable checking of pointers alignment"
depends on UBSAN
default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
help
This option disables the check of unaligned memory accesses.
This option should be used when building allmodconfig.
Disabling this option on architectures that support unaligned
accesses may produce a lot of false positives.
config UBSAN_ALIGNMENT
def_bool !UBSAN_NO_ALIGNMENT
config TEST_UBSAN
tristate "Module for testing for undefined behavior detection"
depends on m && UBSAN
help
This is a test module for UBSAN.
It triggers various undefined behavior, and detect it.
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