KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT

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FGUs don't actually require hardware support, so don't gate fgt trap
config insertion on FGT. This is the only action required to allow FGUs
always, as kvm_calculate_traps() already computes the FGU bits with or
without FEAT_FGT.

This also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1
without FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the
course-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(),
which expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF
will be injected without needing the specific handler.

Fixes: f5a5a406b4 ("KVM: arm64: Propagate and handle Fine-Grained UNDEF bits")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Wei-Lin Chang <weilin.chang@arm.com>
Link: https://patch.msgid.link/20260929090031.3829185-2-fuad.tabba@linux.dev
[oliver: Take Wei-Lin's suggested changelog]
Signed-off-by: Oliver Upton <oupton@kernel.org>

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Fuad Tabba 2026-09-29 10:00:28 +01:00 • committed by Oliver Upton

parent 751f464156

commit 4bdd2b3a70

1 changed files with 0 additions and 3 deletions

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arch/arm64/kvm/emulate-nested.c

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