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Marc Zyngier 9408013caa KVM: arm/arm64: Properly handle faulting of device mappings
commit 6d674e28f6 upstream.

A device mapping is normally always mapped at Stage-2, since there
is very little gain in having it faulted in.

Nonetheless, it is possible to end-up in a situation where the device
mapping has been removed from Stage-2 (userspace munmaped the VFIO
region, and the MMU notifier did its job), but present in a userspace
mapping (userpace has mapped it back at the same address). In such
a situation, the device mapping will be demand-paged as the guest
performs memory accesses.

This requires to be careful when dealing with mapping size, cache
management, and to handle potential execution of a device mapping.

Reported-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Alexandru Elisei <alexandru.elisei@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191211165651.7889-2-maz@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-31 16:46:24 +01:00
..
arm KVM: arm/arm64: Properly handle faulting of device mappings 2019-12-31 16:46:24 +01:00
Kconfig KVM: polling: add architecture backend to disable polling 2019-04-26 09:08:17 +02:00
async_pf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
async_pf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
coalesced_mmio.c KVM: coalesced_mmio: add bounds checking 2019-09-18 15:56:55 +02:00
coalesced_mmio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
eventfd.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
irqchip.c KVM/arm updates for 5.3 2019-07-11 15:14:16 +02:00
kvm_main.c KVM: Add a comment describing the /dev/kvm no_compat handling 2019-11-15 10:14:04 +01:00
vfio.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vfio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00