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7fe2cd4e1a
FEAT_Debugv8p9 is incorrectly defined against ID_AA64DFR0_EL1.PMUVer
instead of ID_AA64DFR0_EL1.DebugVer. All three consumers of the macro
gate features that are architecturally tied to FEAT_Debugv8p9
(DebugVer = 0b1011, DDI0487 M.b A2.2.10):
- HDFGRTR2_EL2.nMDSELR_EL1, HDFGWTR2_EL2.nMDSELR_EL1: MDSELR_EL1
is present only when FEAT_Debugv8p9 is implemented (D24.3.21).
- MDCR_EL2.EBWE: the Extended Breakpoint and Watchpoint Enable bit
is RES0 unless FEAT_Debugv8p9 is implemented (D24.3.17).
Neither register has any dependency on PMUVer.
FEAT_Debugv8p9 and FEAT_PMUv3p9 are independent. Per DDI0487 M.b
A2.2.10, FEAT_Debugv8p9 is unconditionally mandatory from Armv8.9,
whereas FEAT_PMUv3p9 is mandatory only when FEAT_PMUv3 is implemented.
An Armv8.9 CPU without a PMU has DebugVer = 0b1011 but PMUVer = 0b0000,
so the wrong field check would cause KVM to incorrectly treat EBWE and
MDSELR_EL1 as RES0 on such hardware.
Fixes: 4bc0fe0898 ("KVM: arm64: Add sanitisation for FEAT_FGT2 registers")
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260424084908.370776-2-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org