KVM: x86: Do kvm_cpuid_array capacity checks in terminal functions (7c7f9548) · Commits · 戴 / test

Perform the capacity checks on the userspace provided kvm_cpuid_array in the lower __do_cpuid_func() and __do_cpuid_func_emulated(). Pre-checking the array in do_cpuid_func() no longer adds value now that __do_cpuid_func() has been trimmed down to size, i.e. doesn't invoke a big pile of retpolined functions before doing anything useful. Note, __do_cpuid_func() already checks the array capacity via do_host_cpuid(), "moving" the check to __do_cpuid_func() simply means removing a WARN_ON(). Suggested-by:

Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/cpuid.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -473,8 +473,12 @@ static struct kvm_cpuid_entry2 do_host_cpuid(struct kvm_cpuid_array array,

		static int __do_cpuid_func_emulated(struct kvm_cpuid_array *array, u32 func)
		{
		struct kvm_cpuid_entry2 *entry = &array->entries[array->nent];
		struct kvm_cpuid_entry2 *entry;

		if (array->nent >= array->maxnent)
		return -E2BIG;

		entry = &array->entries[array->nent];
		entry->function = func;
		entry->index = 0;
		entry->flags = 0;
		@@ -511,7 +515,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
		r = -E2BIG;

		entry = do_host_cpuid(array, function, 0);
		if (WARN_ON(!entry))
		if (!entry)
		goto out;

		switch (function) {
		@@ -782,9 +786,6 @@ out:
		static int do_cpuid_func(struct kvm_cpuid_array *array, u32 func,
		unsigned int type)
		{
		if (array->nent >= array->maxnent)
		return -E2BIG;

		if (type == KVM_GET_EMULATED_CPUID)
		return __do_cpuid_func_emulated(array, func);

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