On 17.04.19 02:54, Eric Farman wrote: > Fix some warnings from smatch: > > arch/s390/kvm/interrupt.c:2310 get_io_adapter() warn: potential spectre issue 'kvm->arch.adapters' [r] (local cap) > arch/s390/kvm/interrupt.c:2341 register_io_adapter() warn: potential spectre issue 'dev->kvm->arch.adapters' [w] > > Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx> > --- > A recent patch from Paolo [1] acted as a reminder (thanks, Christian!) > that I had one for the s390 KVM code after some code reviews [2]. > Let's clean that up. > > [1] https://patchwork.kernel.org/patch/10895463/ > [2] https://patchwork.kernel.org/patch/10788565/#22484223 > --- > arch/s390/kvm/interrupt.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c > index 82162867f378..bfd55ad34a3e 100644 > --- a/arch/s390/kvm/interrupt.c > +++ b/arch/s390/kvm/interrupt.c > @@ -14,6 +14,7 @@ > #include <linux/kvm_host.h> > #include <linux/hrtimer.h> > #include <linux/mmu_context.h> > +#include <linux/nospec.h> > #include <linux/signal.h> > #include <linux/slab.h> > #include <linux/bitmap.h> > @@ -2307,6 +2308,7 @@ static struct s390_io_adapter *get_io_adapter(struct kvm *kvm, unsigned int id) > { > if (id >= MAX_S390_IO_ADAPTERS) > return NULL; > + id = array_index_nospec(id, MAX_S390_IO_ADAPTERS); > return kvm->arch.adapters[id]; return kvm->arch.adapters[array_index_nospec(id, MAX_S390_IO_ADAPTERS)]; should exactly fit into a single line if I am not wrong. > } > > @@ -2320,8 +2322,13 @@ static int register_io_adapter(struct kvm_device *dev, > (void __user *)attr->addr, sizeof(adapter_info))) > return -EFAULT; > > - if ((adapter_info.id >= MAX_S390_IO_ADAPTERS) || > - (dev->kvm->arch.adapters[adapter_info.id] != NULL)) > + if (adapter_info.id >= MAX_S390_IO_ADAPTERS) > + return -EINVAL; > + > + adapter_info.id = array_index_nospec(adapter_info.id, > + MAX_S390_IO_ADAPTERS); I dislike that we are modifying adapter_info here. Can you use a local variable instead? > + > + if (dev->kvm->arch.adapters[adapter_info.id] != NULL) > return -EINVAL; > > adapter = kzalloc(sizeof(*adapter), GFP_KERNEL); > -- Thanks, David / dhildenb
