Commit-ID: 47bdf3378d62a627cfb8a54e1180c08d67078b61 Gitweb: http://git.kernel.org/tip/47bdf3378d62a627cfb8a54e1180c08d67078b61 Author: He Chen <[email protected]> AuthorDate: Fri, 11 Nov 2016 17:25:35 +0800 Committer: Thomas Gleixner <[email protected]> CommitDate: Wed, 16 Nov 2016 11:13:09 +0100
x86/cpuid: Provide get_scattered_cpuid_leaf() Sparse populated CPUID leafs are collected in a software provided leaf to avoid bloat of the x86_capability array, but there is no way to rebuild the real leafs (e.g. for KVM CPUID enumeration) other than rereading the CPUID leaf from the CPU. While this is possible it is problematic as it does not take software disabled features into account. If a feature is disabled on the host it should not be exposed to a guest either. Add get_scattered_cpuid_leaf() which rebuilds the leaf from the scattered cpuid table information and the active CPU features. [ tglx: Rewrote changelog ] Signed-off-by: He Chen <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Cc: Luwei Kang <[email protected]> Cc: [email protected] Cc: Radim Krčmář <[email protected]> Cc: Piotr Luc <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Paolo Bonzini <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> --- arch/x86/include/asm/processor.h | 3 +++ arch/x86/kernel/cpu/scattered.c | 49 ++++++++++++++++++++++++++++++---------- 2 files changed, 40 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 8f6ac5b..e7f8c62 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -189,6 +189,9 @@ extern void identify_secondary_cpu(struct cpuinfo_x86 *); extern void print_cpu_info(struct cpuinfo_x86 *); void print_cpu_msr(struct cpuinfo_x86 *); extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c); +extern u32 get_scattered_cpuid_leaf(unsigned int level, + unsigned int sub_leaf, + enum cpuid_regs_idx reg); extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c); extern void init_amd_cacheinfo(struct cpuinfo_x86 *c); diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index dbb470e..d1316f9 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -17,24 +17,25 @@ struct cpuid_bit { u32 sub_leaf; }; +/* Please keep the leaf sorted by cpuid_bit.level for faster search. */ +static const struct cpuid_bit cpuid_bits[] = { + { X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 }, + { X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 }, + { X86_FEATURE_INTEL_PT, CPUID_EBX, 25, 0x00000007, 0 }, + { X86_FEATURE_AVX512_4VNNIW, CPUID_EDX, 2, 0x00000007, 0 }, + { X86_FEATURE_AVX512_4FMAPS, CPUID_EDX, 3, 0x00000007, 0 }, + { X86_FEATURE_HW_PSTATE, CPUID_EDX, 7, 0x80000007, 0 }, + { X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 }, + { X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 }, + { 0, 0, 0, 0, 0 } +}; + void init_scattered_cpuid_features(struct cpuinfo_x86 *c) { u32 max_level; u32 regs[4]; const struct cpuid_bit *cb; - static const struct cpuid_bit cpuid_bits[] = { - { X86_FEATURE_INTEL_PT, CPUID_EBX, 25, 0x00000007, 0 }, - { X86_FEATURE_AVX512_4VNNIW, CPUID_EDX, 2, 0x00000007, 0 }, - { X86_FEATURE_AVX512_4FMAPS, CPUID_EDX, 3, 0x00000007, 0 }, - { X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 }, - { X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 }, - { X86_FEATURE_HW_PSTATE, CPUID_EDX, 7, 0x80000007, 0 }, - { X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 }, - { X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 }, - { 0, 0, 0, 0, 0 } - }; - for (cb = cpuid_bits; cb->feature; cb++) { /* Verify that the level is valid */ @@ -51,3 +52,27 @@ void init_scattered_cpuid_features(struct cpuinfo_x86 *c) set_cpu_cap(c, cb->feature); } } + +u32 get_scattered_cpuid_leaf(unsigned int level, unsigned int sub_leaf, + enum cpuid_regs_idx reg) +{ + const struct cpuid_bit *cb; + u32 cpuid_val = 0; + + for (cb = cpuid_bits; cb->feature; cb++) { + + if (level > cb->level) + continue; + + if (level < cb->level) + break; + + if (reg == cb->reg && sub_leaf == cb->sub_leaf) { + if (cpu_has(&boot_cpu_data, cb->feature)) + cpuid_val |= BIT(cb->bit); + } + } + + return cpuid_val; +} +EXPORT_SYMBOL_GPL(get_scattered_cpuid_leaf);
