From 4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Sep 2026 10:00:28 +0100 Subject: [PATCH] KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT 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: f5a5a406b4b8b ("KVM: arm64: Propagate and handle Fine-Grained UNDEF bits") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba Reviewed-by: Wei-Lin Chang Link: https://patch.msgid.link/20260929090031.3829185-2-fuad.tabba@linux.dev [oliver: Take Wei-Lin's suggested changelog] Signed-off-by: Oliver Upton --- arch/arm64/kvm/emulate-nested.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c index 3806ff0920fe..f59d89d04eca 100644 --- a/arch/arm64/kvm/emulate-nested.c +++ b/arch/arm64/kvm/emulate-nested.c @@ -2386,9 +2386,6 @@ int __init populate_nv_trap_config(void) print_nv_trap_error(fgt, "FGT bit is reserved", ret); } - if (!cpus_have_final_cap(ARM64_HAS_FGT)) - continue; - prev = xa_store(&sr_forward_xa, enc, xa_mk_value(tc.val), GFP_KERNEL);