https://github.com/torvalds/linux
Revision 23711a5e662c1a66e14cb9288e7dfd2b840efcd5 authored by Marc Zyngier on 10 November 2020, 14:13:06 UTC, committed by Marc Zyngier on 12 November 2020, 21:22:22 UTC
We now expose ID_AA64PFR0_EL1.CSV2=1 to guests running on hosts
that are immune to Spectre-v2, but that don't have this field set,
most likely because they predate the specification.

However, this prevents the migration of guests that have started on
a host the doesn't fake this CSV2 setting to one that does, as KVM
rejects the write to ID_AA64PFR0_EL2 on the grounds that it isn't
what is already there.

In order to fix this, allow userspace to set this field as long as
this doesn't result in a promising more than what is already there
(setting CSV2 to 0 is acceptable, but setting it to 1 when it is
already set to 0 isn't).

Fixes: e1026237f9067 ("KVM: arm64: Set CSV2 for guests on hardware unaffected by Spectre-v2")
Reported-by: Peng Liang <liangpeng10@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201110141308.451654-2-maz@kernel.org
1 parent 4f6b838
History
Tip revision: 23711a5e662c1a66e14cb9288e7dfd2b840efcd5 authored by Marc Zyngier on 10 November 2020, 14:13:06 UTC
KVM: arm64: Allow setting of ID_AA64PFR0_EL1.CSV2 from userspace
Tip revision: 23711a5
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.clang-format -rw-r--r-- 16.3 KB
.cocciconfig -rw-r--r-- 59 bytes
.get_maintainer.ignore -rw-r--r-- 71 bytes
.gitattributes -rw-r--r-- 62 bytes
.gitignore -rw-r--r-- 1.8 KB
.mailmap -rw-r--r-- 17.4 KB
COPYING -rw-r--r-- 496 bytes
CREDITS -rw-r--r-- 97.6 KB
Kbuild -rw-r--r-- 1.3 KB
Kconfig -rw-r--r-- 555 bytes
MAINTAINERS -rw-r--r-- 563.0 KB
Makefile -rw-r--r-- 62.7 KB
README -rw-r--r-- 727 bytes

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