On 10/31/18 4:49 PM, Marc Orr wrote:
> + if (!boot_cpu_has(X86_FEATURE_FPU) || !boot_cpu_has(X86_FEATURE_FXSR)) {
> + printk(KERN_ERR "kvm: inadequate fpu\n");
> + r = -EOPNOTSUPP;
> + goto out;
> + }
It would be nice to have a comment about _why_ this is inadequate.
> r = -ENOMEM;
> + x86_fpu_cache = kmem_cache_create_usercopy(
> + "x86_fpu",
For now, this should probably be kvm_x86_fpu since it's not used as a
generic x86 thing, yet.
Also, why is this a "usercopy"? "fpu_kernel_xstate_size" includes (or
will soon include) supervisor state which can never be copied to
userspace. If this structure is going out to userspace, that tells me
we might instead want fpu_user_xstate_size, *or* we want the
non-usercopy variant.
