[PATCH v7 12/41] KVM: arm64: gic-v5: Sanitize ID_AA64PFR2_EL1.GCIE

[Mark Brown]

On Thu, Mar 19, 2026 at 03:52:50PM +0000, Sascha Bischoff wrote:
> Add in a sanitization function for ID_AA64PFR2_EL1, preserving the
> already-present behaviour for the FPMR, MTEFAR, and MTESTOREONLY
> fields. Add sanitisation for the GCIE field, which is set to IMP if
> the host supports a GICv5 guest and NI, otherwise.

We're also seeing an issue with this in the aarch32_id_regs test:

# selftests: kvm: aarch32_id_regs
# Random seed: 0x6b8b4567
# ==== Test Assertion Failure ====
#   arm64/aarch32_id_regs.c:25: read_sysreg_s((((3) << 19) | ((0) << 16) | ((0) << 12) | ((1) << 8) | ((1) << 5))) == 0
#   pid=3111 tid=3111 errno=4 - Interrupted system call
# sh: 1: addr2line: not found
#   0x10000000 != 0x0 (read_sysreg_s((((3) << 19) | ((0) << 16) | ((0) << 12) | ((1) << 8) | ((1) << 5))) != 0)
not ok 9 selftests: kvm: aarch32_id_regs # exit=254

which for some reason only manifests on TX2 of the platforms I've seen.

Bisect log:

git bisect start
# status: waiting for both good and bad commits
# bad: [e3d585ed3ff891a00c2284fef4be9cf8581735ab] Merge branch kvm-arm64/vgic-v5-ppi into kvmarm-master/next
git bisect bad e3d585ed3ff891a00c2284fef4be9cf8581735ab
# status: waiting for good commit(s), bad commit known
# good: [f338e77383789c0cae23ca3d48adcc5e9e137e3c] Linux 7.0-rc4
git bisect good f338e77383789c0cae23ca3d48adcc5e9e137e3c
# bad: [0a9f38bf612b195e04236d366ed9f769ce14cc27] KVM: arm64: selftests: Introduce a minimal GICv5 PPI selftest
git bisect bad 0a9f38bf612b195e04236d366ed9f769ce14cc27
# bad: [4d591252bacb2d004b7c7f5db439bfa23b552ee7] KVM: arm64: gic-v5: Implement PPI interrupt injection
git bisect bad 4d591252bacb2d004b7c7f5db439bfa23b552ee7
# good: [da92ff15ca4c5b0f75ec1cb3d2e275db2ff2c810] KVM: arm64: gic-v5: Add Arm copyright header
git bisect good da92ff15ca4c5b0f75ec1cb3d2e275db2ff2c810
# bad: [070543a85adce329672012a1fe35fa48c76e02d5] KVM: arm64: gic-v5: Trap and emulate ICC_IDR0_EL1 accesses
git bisect bad 070543a85adce329672012a1fe35fa48c76e02d5
# bad: [a258a383b91774ac646517ec1003a442964d8946] KVM: arm64: gic-v5: Sanitize ID_AA64PFR2_EL1.GCIE
git bisect bad a258a383b91774ac646517ec1003a442964d8946
# good: [f656807150e3e1c6f76cab918e5adfad6d881d58] KVM: arm64: gic-v5: Detect implemented PPIs on boot
git bisect good f656807150e3e1c6f76cab918e5adfad6d881d58
# first bad commit: [a258a383b91774ac646517ec1003a442964d8946] KVM: arm64: gic-v5: Sanitize ID_AA64PFR2_EL1.GCIE
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