[PATCH v1 1/2] arm64/cpufeature: Add feature detection for fine grained traps
Mark Brown
broonie at kernel.org
Thu Oct 27 13:52:45 PDT 2022
Virtualisation support for SME depends on FEAT_FGT since it uses fine
grained traps to control access to SMPRI_EL1 and (for nVHE) TPIDR2_EL0
but systems have been encountered which implement SME without VHE. In
order to work around such systems we need to detect the absence of
FEAT_FGT, add detection in the cpufeature code.
Signed-off-by: Mark Brown <broonie at kernel.org>
---
arch/arm64/kernel/cpufeature.c | 11 +++++++++++
arch/arm64/tools/cpucaps | 1 +
2 files changed, 12 insertions(+)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6062454a9067..8ded72a8ccee 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2590,6 +2590,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.matches = has_cpuid_feature,
.min_field_value = 1,
},
+ {
+ .desc = "Fine Grained Traps",
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .capability = ARM64_HAS_FGT,
+ .sys_reg = SYS_ID_AA64MMFR0_EL1,
+ .sign = FTR_UNSIGNED,
+ .field_pos = ID_AA64MMFR0_EL1_FGT_SHIFT,
+ .field_width = ID_AA64MMFR0_EL1_FGT_WIDTH,
+ .min_field_value = ID_AA64MMFR0_EL1_FGT_IMP,
+ .matches = has_cpuid_feature,
+ },
#ifdef CONFIG_ARM64_SME
{
.desc = "Scalable Matrix Extension",
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index f1c0347ec31a..2553c7559412 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -23,6 +23,7 @@ HAS_DCPOP
HAS_E0PD
HAS_ECV
HAS_EPAN
+HAS_FGT
HAS_GENERIC_AUTH
HAS_GENERIC_AUTH_ARCH_QARMA3
HAS_GENERIC_AUTH_ARCH_QARMA5
--
2.30.2
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