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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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47bdf3378d
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 <he.chen@linux.intel.com> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Luwei Kang <luwei.kang@intel.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Piotr Luc <Piotr.Luc@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Link: http://lkml.kernel.org/r/1478856336-9388-3-git-send-email-he.chen@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
79 lines
1.9 KiB
C
79 lines
1.9 KiB
C
/*
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* Routines to identify additional cpu features that are scattered in
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* cpuid space.
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*/
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#include <linux/cpu.h>
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#include <asm/pat.h>
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#include <asm/processor.h>
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#include <asm/apic.h>
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struct cpuid_bit {
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u16 feature;
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u8 reg;
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u8 bit;
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u32 level;
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u32 sub_leaf;
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};
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/* Please keep the leaf sorted by cpuid_bit.level for faster search. */
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static const struct cpuid_bit cpuid_bits[] = {
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{ X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 },
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{ X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 },
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{ X86_FEATURE_INTEL_PT, CPUID_EBX, 25, 0x00000007, 0 },
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{ X86_FEATURE_AVX512_4VNNIW, CPUID_EDX, 2, 0x00000007, 0 },
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{ X86_FEATURE_AVX512_4FMAPS, CPUID_EDX, 3, 0x00000007, 0 },
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{ X86_FEATURE_HW_PSTATE, CPUID_EDX, 7, 0x80000007, 0 },
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{ X86_FEATURE_CPB, CPUID_EDX, 9, 0x80000007, 0 },
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{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
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{ 0, 0, 0, 0, 0 }
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};
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void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
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{
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u32 max_level;
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u32 regs[4];
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const struct cpuid_bit *cb;
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for (cb = cpuid_bits; cb->feature; cb++) {
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/* Verify that the level is valid */
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max_level = cpuid_eax(cb->level & 0xffff0000);
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if (max_level < cb->level ||
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max_level > (cb->level | 0xffff))
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continue;
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cpuid_count(cb->level, cb->sub_leaf, ®s[CPUID_EAX],
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®s[CPUID_EBX], ®s[CPUID_ECX],
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®s[CPUID_EDX]);
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if (regs[cb->reg] & (1 << cb->bit))
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set_cpu_cap(c, cb->feature);
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}
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}
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u32 get_scattered_cpuid_leaf(unsigned int level, unsigned int sub_leaf,
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enum cpuid_regs_idx reg)
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{
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const struct cpuid_bit *cb;
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u32 cpuid_val = 0;
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for (cb = cpuid_bits; cb->feature; cb++) {
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if (level > cb->level)
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continue;
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if (level < cb->level)
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break;
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if (reg == cb->reg && sub_leaf == cb->sub_leaf) {
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if (cpu_has(&boot_cpu_data, cb->feature))
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cpuid_val |= BIT(cb->bit);
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}
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}
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return cpuid_val;
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}
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EXPORT_SYMBOL_GPL(get_scattered_cpuid_leaf);
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