From: Sean Christopherson Date: Mon, 2 Mar 2020 23:56:56 +0000 (-0800) Subject: KVM: x86: Do kvm_cpuid_array capacity checks in terminal functions X-Git-Tag: libata-5.7-2020-04-09~64^2~89 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=7c7f9548108926dbf6776b1cfe748f7c617cfd36;p=linux-2.6-block.git KVM: x86: Do kvm_cpuid_array capacity checks in terminal functions 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 Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 214bcb3a5c1e..1934f5d6b731 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -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);