KVM: x86: Refactor out-of-range logic to contain the madness (09c7431e) · Commits · 戴 / test

arch/x86/kvm/cpuid.c

+29 −18

Original line number	Diff line number	Diff line
		@@ -945,13 +945,19 @@ EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
		* - HyperV: 0x40000000 - 0x400000ff
		* - KVM: 0x40000100 - 0x400001ff
		*/
		static bool cpuid_function_in_range(struct kvm_vcpu *vcpu, u32 function)
		static struct kvm_cpuid_entry2 *
		get_out_of_range_cpuid_entry(struct kvm_vcpu vcpu, u32 fn_ptr, u32 index)
		{
		struct kvm_cpuid_entry2 basic, class;
		u32 function = *fn_ptr;

		basic = kvm_find_cpuid_entry(vcpu, 0, 0);
		if (!basic)
		return true;
		return NULL;

		if (is_guest_vendor_amd(basic->ebx, basic->ecx, basic->edx) \|\|
		is_guest_vendor_hygon(basic->ebx, basic->ecx, basic->edx))
		return NULL;

		if (function >= 0x40000000 && function <= 0x4fffffff)
		class = kvm_find_cpuid_entry(vcpu, function & 0xffffff00, 0);
		@@ -960,7 +966,23 @@ static bool cpuid_function_in_range(struct kvm_vcpu *vcpu, u32 function)
		else
		class = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);

		return class && function <= class->eax;
		if (class && function <= class->eax)
		return NULL;

		/*
		* Leaf specific adjustments are also applied when redirecting to the
		* max basic entry, e.g. if the max basic leaf is 0xb but there is no
		* entry for CPUID.0xb.index (see below), then the output value for EDX
		* needs to be pulled from CPUID.0xb.1.
		*/
		*fn_ptr = basic->eax;

		/*
		* The class does not exist or the requested function is out of range;
		* the effective CPUID entry is the max basic leaf. Note, the index of
		* the original requested leaf is observed!
		*/
		return kvm_find_cpuid_entry(vcpu, basic->eax, index);
		}

		bool kvm_cpuid(struct kvm_vcpu vcpu, u32 eax, u32 *ebx,
		@@ -968,25 +990,14 @@ bool kvm_cpuid(struct kvm_vcpu vcpu, u32 eax, u32 *ebx,
		{
		u32 orig_function = eax, function = eax, index = *ecx;
		struct kvm_cpuid_entry2 *entry;
		struct kvm_cpuid_entry2 *max;
		bool found;

		entry = kvm_find_cpuid_entry(vcpu, function, index);
		found = entry;
		/*
		* Intel CPUID semantics treats any query for an out-of-range
		* leaf as if the highest basic leaf (i.e. CPUID.0H:EAX) were
		* requested. AMD CPUID semantics returns all zeroes for any
		* undefined leaf, whether or not the leaf is in range.
		*/
		if (!entry && check_limit && !guest_cpuid_is_amd_or_hygon(vcpu) &&
		!cpuid_function_in_range(vcpu, function)) {
		max = kvm_find_cpuid_entry(vcpu, 0, 0);
		if (max) {
		function = max->eax;
		entry = kvm_find_cpuid_entry(vcpu, function, index);
		}
		}

		if (!entry && check_limit)
		entry = get_out_of_range_cpuid_entry(vcpu, &function, index);

		if (entry) {
		*eax = entry->eax;
		*ebx = entry->ebx;

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