KVM: arm64: Skip cache maintenance for non-cacheable pKVM mappings

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The pKVM flush path walks its own pkvm_mappings list and cleans the
data cache for every mapping, unlike the generic stage-2 walker it
shadows, which skips non-cacheable leaves. Cleaning the cacheable
alias of a non-cacheable mapping is pointless and can corrupt a
device endpoint. Record whether a mapping is non-cacheable in spare
bits of nr_pages and skip cache maintenance for it.

Fixes: e912efed48 ("KVM: arm64: Introduce the EL1 pKVM MMU")
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Bradley Morgan <include@grrlz.net>
[tabba: use Marc's anonymous bitfield in place of the open-coded mask and helpers]
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Tested-by: Bradley Morgan <include@grrlz.net> # On pixel 7, Android 17 CP2A.260705.006
Test: Bradley Morgan <include@grrlz.net> # On QEMU arm64 host
Link: https://patch.msgid.link/20260717130317.1953574-2-fuad.tabba@linux.dev
Signed-off-by: Oliver Upton <oupton@kernel.org>

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Bradley Morgan 2026-07-17 14:03:11 +01:00 • committed by Oliver Upton

parent 734dc8c01c

commit fff4eb33ff

2 changed files with 13 additions and 7 deletions

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5

arch/arm64/include/asm/kvm_pkvm.h

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15

arch/arm64/kvm/pkvm.c

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