[PATCH v3 15/22] arm64: capabilities: Change scope of VHE to Boot CPU feature
From: Dave.Martin@arm.com (Dave Martin)
Date: 2018-02-12 17:17:34
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On Fri, Feb 09, 2018 at 05:54:59PM +0000, Suzuki K Poulose wrote:
We expect all CPUs to be running at the same EL inside the kernel with or without VHE enabled and we have strict checks to ensure that any mismatch triggers a kernel panic. If VHE is enabled, we use the feature based on the boot CPU and all other CPUs should follow. This makes it a perfect candidate for a cpability
capability
quoted hunk ↗ jump to hunk
based on the boot CPU, which should be matched by all the CPUs (both when is ON and OFF). This saves us some not-so-pretty hooks and special code, just for verifying the conflict. Cc: Marc Zyngier <redacted> Cc: Dave Martin <dave.martin@arm.com> Cc: Will Deacon <redacted> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- arch/arm64/include/asm/cpufeature.h | 7 +++++++ arch/arm64/include/asm/virt.h | 6 ------ arch/arm64/kernel/cpufeature.c | 5 +++-- arch/arm64/kernel/smp.c | 38 ------------------------------------- 4 files changed, 10 insertions(+), 46 deletions(-)diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 5f56a8342065..dfce93f79ae7 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h@@ -276,6 +276,13 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; (ARM64_CPUCAP_SCOPE_LOCAL_CPU | \ ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU) +/* + * Critical CPU feature used early in the boot based on the boot CPU. + * The feature should be matched by all booting CPU (both miss and hit + * cases). + */ +#define ARM64_CPUCAP_CRITICAL_BOOT_CPU_FEATURE ARM64_CPUCAP_SCOPE_BOOT_CPU +
Nit: would it be consistent with the uses we already have for the word "strict" to use that word here? i.e., ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE. Or do you think that would be more confusing? Otherwise, "critical" sounds a bit like we depend on the capability being available. If "strict" doesn't fit though and no other option suggests itself, it's probably not worth changing this.
quoted hunk ↗ jump to hunk
struct arm64_cpu_capabilities { const char *desc; u16 capability;diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index c5f89442785c..9d1e24e030b3 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h@@ -102,12 +102,6 @@ static inline bool has_vhe(void) return false; } -#ifdef CONFIG_ARM64_VHE -extern void verify_cpu_run_el(void); -#else -static inline void verify_cpu_run_el(void) {} -#endif - #endif /* __ASSEMBLY__ */ #endif /* ! __ASM__VIRT_H */diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 7625e2962e2b..f66e66c79916 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c@@ -1016,11 +1016,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { }, #endif /* CONFIG_ARM64_PAN */ { +#ifdef CONFIG_ARM64_VHE .desc = "Virtualization Host Extensions", .capability = ARM64_HAS_VIRT_HOST_EXTN, - .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .type = ARM64_CPUCAP_CRITICAL_BOOT_CPU_FEATURE, .matches = runs_at_el2, .cpu_enable = cpu_copy_el2regs, +#endif
Shouldn't the #ifdef...#endif be outside the { ... },?
Otherwise this yields an empty block that will truncate the list in the
CONFIG_ARM64_VHE case...
Removal of this block for !CONFIG_ARM64_VHE is a change rather than just
refactoring, so the commit message should explain it.
[...]
Cheers
---Dave