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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-03-02 15:56:56 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 17:58:35 +0100 |
| commit | 7c7f9548108926dbf6776b1cfe748f7c617cfd36 (patch) | |
| tree | ed3301ab926340c9a83b7871cdc3fdff5edfa4d4 /arch/x86/kvm/cpuid.c | |
| parent | dd69cc2542f728179d5a0ae1c972813f88ab14aa (diff) | |
| download | lwn-7c7f9548108926dbf6776b1cfe748f7c617cfd36.tar.gz lwn-7c7f9548108926dbf6776b1cfe748f7c617cfd36.zip | |
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 <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 11 |
1 files changed, 6 insertions, 5 deletions
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); |