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.

...

All of this extra work is required to make sure that "legacy" GICv3
guests based on QEMU transparently work on compatible GICv5 hosts
without modification.

I'm seeing a regression in -next in set_id_regs on a range of platforms,
including physical ones like the Toradex Verdin AM62 and i.MX8MP-EVK,
with a GICv3:

# ok 105 # SKIP MTE capability not supported, nothing to test
# ==== Test Assertion Failure ====
#   arm64/set_id_regs.c:651: test_reg_vals[encoding_to_range_idx(uc.args[2])] == uc.args[3]
#   pid=3573 tid=3573 errno=4 - Interrupted system call
#      1	0x0000000000403047: test_guest_reg_read at set_id_regs.c:651
#      2	0x00000000004024cb: main at set_id_regs.c:805
#      3	0x0000ffff9e85251b: ?? ??:0
#      4	0x0000ffff9e8525fb: ?? ??:0
#      5	0x00000000004027af: _start at ??:?
#   0x1111 != 0x1001111 (test_reg_vals[encoding_to_range_idx(uc.args[2])] != uc.args[3])
not ok 20 selftests: kvm: set_id_regs # exit=254

Platforms without a GICv3 appear unaffected.

Full log:

   https://lava.sirena.org.uk/scheduler/job/2584795#L4111

bisect log:

# bad: [0ec822710d040a1e4a13be04494dc9f0462f8ba7] Merge branch 'for-linux-next-fixes' of https://gitlab.freedesktop.org/drm/misc/kernel.git
# good: [0e4f8f1a3d081e834be5fd0a62bdb2554fadd307] Merge tag 'parisc-for-7.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
# good: [09e70e4f119ff650d24c96161fd2f62ac7e424b0] regmap: Synchronize cache for the page selector
git bisect start '0ec822710d040a1e4a13be04494dc9f0462f8ba7' '0e4f8f1a3d081e834be5fd0a62bdb2554fadd307' '09e70e4f119ff650d24c96161fd2f62ac7e424b0'
# test job: [09e70e4f119ff650d24c96161fd2f62ac7e424b0] https://lava.sirena.org.uk/scheduler/job/2565604
# test job: [0ec822710d040a1e4a13be04494dc9f0462f8ba7] https://lava.sirena.org.uk/scheduler/job/2584795
# bad: [0ec822710d040a1e4a13be04494dc9f0462f8ba7] Merge branch 'for-linux-next-fixes' of https://gitlab.freedesktop.org/drm/misc/kernel.git
git bisect bad 0ec822710d040a1e4a13be04494dc9f0462f8ba7
# test job: [a5d4dfaac4b2810ec2be80d2a9a1facce7dc554d] https://lava.sirena.org.uk/scheduler/job/2584889
# good: [a5d4dfaac4b2810ec2be80d2a9a1facce7dc554d] Merge branch 'mtd/fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git
git bisect good a5d4dfaac4b2810ec2be80d2a9a1facce7dc554d
# test job: [d04c0e637ff3323b010804dbfe349fb9c1309253] https://lava.sirena.org.uk/scheduler/job/2585075
# bad: [d04c0e637ff3323b010804dbfe349fb9c1309253] Merge branch 'dma-mapping-fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux.git
git bisect bad d04c0e637ff3323b010804dbfe349fb9c1309253
# test job: [e3d585ed3ff891a00c2284fef4be9cf8581735ab] https://lava.sirena.org.uk/scheduler/job/2585150
# bad: [e3d585ed3ff891a00c2284fef4be9cf8581735ab] Merge branch kvm-arm64/vgic-v5-ppi into kvmarm-master/next
git bisect bad e3d585ed3ff891a00c2284fef4be9cf8581735ab
# test job: [0a9f38bf612b195e04236d366ed9f769ce14cc27] https://lava.sirena.org.uk/scheduler/job/2585330
# bad: [0a9f38bf612b195e04236d366ed9f769ce14cc27] KVM: arm64: selftests: Introduce a minimal GICv5 PPI selftest
git bisect bad 0a9f38bf612b195e04236d366ed9f769ce14cc27
# test job: [4d591252bacb2d004b7c7f5db439bfa23b552ee7] https://lava.sirena.org.uk/scheduler/job/2585661
# bad: [4d591252bacb2d004b7c7f5db439bfa23b552ee7] KVM: arm64: gic-v5: Implement PPI interrupt injection
git bisect bad 4d591252bacb2d004b7c7f5db439bfa23b552ee7
# test job: [da92ff15ca4c5b0f75ec1cb3d2e275db2ff2c810] https://lava.sirena.org.uk/scheduler/job/2585906
# good: [da92ff15ca4c5b0f75ec1cb3d2e275db2ff2c810] KVM: arm64: gic-v5: Add Arm copyright header
git bisect good da92ff15ca4c5b0f75ec1cb3d2e275db2ff2c810
# test job: [070543a85adce329672012a1fe35fa48c76e02d5] https://lava.sirena.org.uk/scheduler/job/2586294
# bad: [070543a85adce329672012a1fe35fa48c76e02d5] KVM: arm64: gic-v5: Trap and emulate ICC_IDR0_EL1 accesses
git bisect bad 070543a85adce329672012a1fe35fa48c76e02d5
# test job: [a258a383b91774ac646517ec1003a442964d8946] https://lava.sirena.org.uk/scheduler/job/2586455
# bad: [a258a383b91774ac646517ec1003a442964d8946] KVM: arm64: gic-v5: Sanitize ID_AA64PFR2_EL1.GCIE
git bisect bad a258a383b91774ac646517ec1003a442964d8946
# test job: [f656807150e3e1c6f76cab918e5adfad6d881d58] https://lava.sirena.org.uk/scheduler/job/2586592
# 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