| Message ID | 20200302235709.27467-54-sean.j.christopherson@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: Introduce KVM cpu caps | expand |
Sean Christopherson <sean.j.christopherson@intel.com> writes: > 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> > --- > arch/x86/kvm/cpuid.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index eebd7f613f67..f879fcbd6fb2 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -478,8 +478,12 @@ 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; > @@ -516,7 +520,7 @@ 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) { > @@ -787,9 +791,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) > 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); Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index eebd7f613f67..f879fcbd6fb2 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -478,8 +478,12 @@ 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; @@ -516,7 +520,7 @@ 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) { @@ -787,9 +791,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function) 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);
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> --- arch/x86/kvm/cpuid.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)