Commit b0c756fe authored by Kristina Martsenko's avatar Kristina Martsenko Committed by Catalin Marinas
Browse files

arm64: cpufeature: detect FEAT_HCX 



Detect if the system has the new HCRX_EL2 register added in ARMv8.7/9.2,
so that subsequent patches can check for its presence.

KVM currently relies on the register being present on all CPUs (or
none), so the kernel will panic if that is not the case. Fortunately no
such systems currently exist, but this can be revisited if they appear.
Note that the kernel will not panic if CONFIG_KVM is disabled.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarKristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20230509142235.3284028-3-kristina.martsenko@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent af94aad4

arch/arm64/kernel/cpufeature.c

+8 −0
Original line number Diff line number Diff line
@@ -364,6 +364,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = { 
static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_TIDCP1_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_AFP_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_HCX_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_ETS_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_TWED_SHIFT, 4, 0),

	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_XNX_SHIFT, 4, 0),
@@ -2309,6 +2310,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { 
		.type = ARM64_CPUCAP_SYSTEM_FEATURE,

		.matches = is_kvm_protected_mode,

	},

	{

		.desc = "HCRX_EL2 register",

		.capability = ARM64_HAS_HCX,

		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,

		.matches = has_cpuid_feature,

		ARM64_CPUID_FIELDS(ID_AA64MMFR1_EL1, HCX, IMP)

	},

#endif

	{

		.desc = "Kernel page table isolation (KPTI)",

arch/arm64/tools/cpucaps

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ HAS_GENERIC_AUTH_IMP_DEF 
HAS_GIC_CPUIF_SYSREGS

HAS_GIC_PRIO_MASKING

HAS_GIC_PRIO_RELAXED_SYNC

HAS_HCX

HAS_LDAPR

HAS_LSE_ATOMICS

HAS_NESTED_VIRT