KVM: x86: Extract code for generating per-entry emulated CPUID information

Extract the meat of __do_cpuid_func_emulated() into a separate helper,
cpuid_func_emulated(), so that cpuid_func_emulated() can be used with a
single CPUID entry.  This will allow marking emulated features as fully
supported in the guest cpu_caps without needing to hardcode the set of
emulated features in multiple locations.

No functional change intended.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20241128013424.4096668-43-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ad8e33f3555329f1e1f0d73fa372f42d97260e57..a4d24d04f0b188a575569db42a5d6335d653fb00 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1213,14 +1213,10 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,
        return entry;
 }
 
-static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
+static int cpuid_func_emulated(struct kvm_cpuid_entry2 *entry, u32 func)
 {
-       struct kvm_cpuid_entry2 *entry;
-
-       if (array->nent >= array->maxnent)
-               return -E2BIG;
+       memset(entry, 0, sizeof(*entry));
 
-       entry = &array->entries[array->nent];
        entry->function = func;
        entry->index = 0;
        entry->flags = 0;
@@ -1228,23 +1224,27 @@ static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
        switch (func) {
        case 0:
                entry->eax = 7;
-               ++array->nent;
-               break;
+               return 1;
        case 1:
                entry->ecx = feature_bit(MOVBE);
-               ++array->nent;
-               break;
+               return 1;
        case 7:
                entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
                entry->eax = 0;
                if (kvm_cpu_cap_has(X86_FEATURE_RDTSCP))
                        entry->ecx = feature_bit(RDPID);
-               ++array->nent;
-               break;
+               return 1;
        default:
-               break;
+               return 0;
        }
+}
+
+static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
+{
+       if (array->nent >= array->maxnent)
+               return -E2BIG;
 
+       array->nent += cpuid_func_emulated(&array->entries[array->nent], func);
        return 0;
 }