From: Sascha Bischoff Date: Thu, 28 Aug 2025 10:59:42 +0000 (+0000) Subject: arm64: cpucaps: Add GICv5 Legacy vCPU interface (GCIE_LEGACY) capability X-Git-Tag: v6.18-rc1~95^2~5^2~5^2~2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7847f51189343b29a24ca7edafb60a9032d5acf8;p=thirdparty%2Fkernel%2Flinux.git arm64: cpucaps: Add GICv5 Legacy vCPU interface (GCIE_LEGACY) capability Implement the GCIE_LEGACY capability as a system feature to be able to check for support from KVM. The type is explicitly ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE, which means that the capability is enabled early if all boot CPUs support it. Additionally, if this capability is enabled during boot, it prevents late onlining of CPUs that lack it, thereby avoiding potential mismatched configurations which would break KVM. Signed-off-by: Sascha Bischoff Reviewed-by: Suzuki K Poulose Reviewed-by: Oliver Upton Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index ef269a5a37e12..770a41fa7214d 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2539,6 +2539,15 @@ test_has_mpam_hcr(const struct arm64_cpu_capabilities *entry, int scope) return idr & MPAMIDR_EL1_HAS_HCR; } +static bool +test_has_gicv5_legacy(const struct arm64_cpu_capabilities *entry, int scope) +{ + if (!this_cpu_has_cap(ARM64_HAS_GICV5_CPUIF)) + return false; + + return !!(read_sysreg_s(SYS_ICC_IDR0_EL1) & ICC_IDR0_EL1_GCIE_LEGACY); +} + static const struct arm64_cpu_capabilities arm64_features[] = { { .capability = ARM64_ALWAYS_BOOT, @@ -3156,6 +3165,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64PFR2_EL1, GCIE, IMP) }, + { + .desc = "GICv5 Legacy vCPU interface", + .type = ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE, + .capability = ARM64_HAS_GICV5_LEGACY, + .matches = test_has_gicv5_legacy, + }, {}, }; diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 9ff5cdbd27597..1b32c1232d28d 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -37,6 +37,7 @@ HAS_GENERIC_AUTH_ARCH_QARMA5 HAS_GENERIC_AUTH_IMP_DEF HAS_GICV3_CPUIF HAS_GICV5_CPUIF +HAS_GICV5_LEGACY HAS_GIC_PRIO_MASKING HAS_GIC_PRIO_RELAXED_SYNC HAS_HCR_NV1