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author | Oliver Upton <oliver.upton@linux.dev> | 2025-09-12 14:22:52 -0700 |
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committer | Marc Zyngier <maz@kernel.org> | 2025-09-19 14:01:35 +0100 |
commit | 7cbdb25bed4046dacf139cce25fad9ef39a04a5f (patch) | |
tree | a10ebebdf279a0e360bb6e97e80a0c0815b5ee82 /scripts/gdb/linux/timerlist.py | |
parent | 26785cf28bb10bc94b2a52820c8ba1b3cfc534e5 (diff) |
KVM: arm64: nv: Expose FEAT_ECBHB to NV-enabled VMs
The exact wording of the restrictions on branch prediction due to
FEAT_ECBHB in DDI0487L.b is as follows:
When FEAT_ECBHB is implemented, the branch history information created
in a context before an exception to a higher Exception level using
AArch64 cannot be used by code before that exception to exploitatively
control the execution of any indirect branches in code in a different
context after the exception.
While vEL2 and EL1 are multiplexed at EL1, they exist in different
hardware-described contexts as KVM uses different stage-2 MMUs to
represent the corresponding translation regimes. Additionally, exception
entries into vEL2 always imply a hardware exception entry into literal EL2
for the emulated regime change.
Given all of this, and the fact that FEAT_ECBHB places no limitation on
the EL of the protected context after the exception, we can claim
FEAT_ECBHB on supporting hardware.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'scripts/gdb/linux/timerlist.py')
0 files changed, 0 insertions, 0 deletions