Commit bcf600ca authored Mar 02, 2020 by Sean Christopherson Committed by Paolo Bonzini Mar 16, 2020

KVM: x86: Remove the unnecessary loop on CPUID 0x7 sub-leafs

Explicitly handle CPUID 0x7 sub-leaf 1. The kernel is currently aware
of exactly one feature in CPUID 0x7.1, which means there is room for
another 127 features before CPUID 0x7.2 will see the light of day, i.e.
the looping is likely to be dead code for years to come.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 09f628a0

arch/x86/kvm/cpuid.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -536,11 +536,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
		if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
		cpuid_entry_set(entry, X86_FEATURE_SPEC_CTRL_SSBD);

		for (i = 1, max_idx = entry->eax; i <= max_idx; i++) {
		if (WARN_ON_ONCE(i > 1))
		break;

		entry = do_host_cpuid(array, function, i);
		/* KVM only supports 0x7.0 and 0x7.1, capped above via min(). */
		if (entry->eax == 1) {
		entry = do_host_cpuid(array, function, 1);
		if (!entry)
		goto out;