[PATCH v2 2/6] KVM: arm64: Move GICv3 broken SEIS implementation detection to a CPU errrata
From: Marc Zyngier <maz@kernel.org>
Date: 2026-07-21 17:08:06
Also in:
kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Using is_midr_in_range_list() in a noinstr function isn't a good idea. And yet kvm_compute_ich_hcr_trap_bits() is doing that by calling vgic_v3_broken_seis(). Move all the broken SEIS detection logic to the errata detection framework, and use a new ARM64_WORKAROUND_GICv3_BROKEN_SEIS cap to indicate that we're running on broken CPUs. This reuses the MIDR list used for IMPDEF PMU detection, which has a 100% overlap with the SEIS stuff... Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kernel/cpu_errata.c | 17 +++++++++++++++-- arch/arm64/kvm/vgic/vgic-v3.c | 26 +++----------------------- arch/arm64/tools/cpucaps | 1 + 3 files changed, 19 insertions(+), 25 deletions(-)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 1995e1198648e..78e4e105f6ab5 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c@@ -272,7 +272,7 @@ has_neoverse_n1_erratum_1542419(const struct arm64_cpu_capabilities *entry, return is_midr_in_range(&range) && has_dic; } -static const struct midr_range impdef_pmuv3_cpus[] = { +static const struct midr_range apple_cpus[] = { MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM), MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM), MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_PRO),
@@ -301,7 +301,14 @@ static bool has_impdef_pmuv3(const struct arm64_cpu_capabilities *entry, int sco if (pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF) return false; - return is_midr_in_range_list(impdef_pmuv3_cpus); + return is_midr_in_range_list(apple_cpus); +} + +static bool has_broken_gic_v3_seis(const struct arm64_cpu_capabilities *entry, int scope) +{ + return (is_kernel_in_hyp_mode() && + is_midr_in_range_list(apple_cpus) && + (read_sysreg_s(SYS_ICH_VTR_EL2) & ICH_VTR_EL2_SEIS)); } static void cpu_enable_impdef_pmuv3_traps(const struct arm64_cpu_capabilities *__unused)
@@ -1009,6 +1016,12 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .matches = has_impdef_pmuv3, .cpu_enable = cpu_enable_impdef_pmuv3_traps, }, + { + .desc = "Known broken GICv3 SEIS implementation", + .capability = ARM64_WORKAROUND_GICv3_BROKEN_SEIS, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_broken_gic_v3_seis, + }, { } };
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 9e841e7afd4a7..0991a649a5d1e 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c@@ -809,27 +809,9 @@ static int __init early_gicv4_enable(char *buf) } early_param("kvm-arm.vgic_v4_enable", early_gicv4_enable); -static const struct midr_range broken_seis[] = { - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM), - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM), - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_PRO), - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_PRO), - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_MAX), - MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_MAX), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD_PRO), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE_PRO), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD_MAX), - MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE_MAX), - {}, -}; - -static bool vgic_v3_broken_seis(void) +static __always_inline bool vgic_v3_broken_seis(void) { - return (is_kernel_in_hyp_mode() && - is_midr_in_range_list(broken_seis) && - (read_sysreg_s(SYS_ICH_VTR_EL2) & ICH_VTR_EL2_SEIS)); + return cpus_have_cap(ARM64_WORKAROUND_GICv3_BROKEN_SEIS); } void noinstr kvm_compute_ich_hcr_trap_bits(struct alt_instr *alt,
@@ -959,10 +941,8 @@ int vgic_v3_probe(const struct gic_kvm_info *info) if (has_v2) static_branch_enable(&vgic_v3_has_v2_compat); - if (vgic_v3_broken_seis()) { - kvm_info("GICv3 with broken locally generated SEI\n"); + if (vgic_v3_broken_seis()) kvm_vgic_global_state.ich_vtr_el2 &= ~ICH_VTR_EL2_SEIS; - } vgic_v3_enable_cpuif_traps();
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 9b85a84f6fd49..50373264ecde8 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps@@ -121,6 +121,7 @@ WORKAROUND_CAVIUM_TX2_219_TVM WORKAROUND_CLEAN_CACHE WORKAROUND_DEVICE_LOAD_ACQUIRE WORKAROUND_DISABLE_CNP +WORKAROUND_GICv3_BROKEN_SEIS WORKAROUND_PMUV3_IMPDEF_TRAPS WORKAROUND_QCOM_FALKOR_E1003 WORKAROUND_QCOM_ORYON_CNTVOFF
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2.47.3