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    Subject[PATCH v2 03/66] KVM: x86: Simplify handling of Centaur CPUID leafs
    Date
    Refactor the handling of the Centaur-only CPUID leaf to detect the leaf
    via a runtime query instead of adding a one-off callback in the static
    array. When the callback was introduced, there were additional fields
    in the array's structs, and more importantly, retpoline wasn't a thing.

    No functional change intended.

    Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
    Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
    ---
    arch/x86/kvm/cpuid.c | 32 ++++++++++----------------------
    1 file changed, 10 insertions(+), 22 deletions(-)

    diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
    index f49fdd06f511..de52cbb46171 100644
    --- a/arch/x86/kvm/cpuid.c
    +++ b/arch/x86/kvm/cpuid.c
    @@ -829,15 +829,7 @@ static int do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 func,
    return __do_cpuid_func(entry, func, nent, maxnent);
    }

    -struct kvm_cpuid_param {
    - u32 func;
    - bool (*qualifier)(const struct kvm_cpuid_param *param);
    -};
    -
    -static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
    -{
    - return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
    -}
    +#define CENTAUR_CPUID_SIGNATURE 0xC0000000

    static int get_cpuid_func(struct kvm_cpuid_entry2 *entries, u32 func,
    int *nent, int maxnent, unsigned int type)
    @@ -845,6 +837,10 @@ static int get_cpuid_func(struct kvm_cpuid_entry2 *entries, u32 func,
    u32 limit;
    int r;

    + if (func == CENTAUR_CPUID_SIGNATURE &&
    + boot_cpu_data.x86_vendor != X86_VENDOR_CENTAUR)
    + return 0;
    +
    r = do_cpuid_func(&entries[*nent], func, nent, maxnent, type);
    if (r)
    return r;
    @@ -896,11 +892,8 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
    struct kvm_cpuid_entry2 *cpuid_entries;
    int nent = 0, r = -E2BIG, i;

    - static const struct kvm_cpuid_param param[] = {
    - { .func = 0 },
    - { .func = 0x80000000 },
    - { .func = 0xC0000000, .qualifier = is_centaur_cpu },
    - { .func = KVM_CPUID_SIGNATURE },
    + static const u32 funcs[] = {
    + 0, 0x80000000, CENTAUR_CPUID_SIGNATURE, KVM_CPUID_SIGNATURE,
    };

    if (cpuid->nent < 1)
    @@ -918,14 +911,9 @@ int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
    goto out;

    r = 0;
    - for (i = 0; i < ARRAY_SIZE(param); i++) {
    - const struct kvm_cpuid_param *ent = &param[i];
    -
    - if (ent->qualifier && !ent->qualifier(ent))
    - continue;
    -
    - r = get_cpuid_func(cpuid_entries, ent->func, &nent,
    - cpuid->nent, type);
    + for (i = 0; i < ARRAY_SIZE(funcs); i++) {
    + r = get_cpuid_func(cpuid_entries, funcs[i], &nent, cpuid->nent,
    + type);
    if (r)
    goto out_free;
    }
    --
    2.24.1
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