On Thu, 01 Dec 2022 18:44:56 +0100 Janis Schoetterl-Glausch scgl@linux.ibm.com wrote:
please also document -EOPNOTSUPP
I'd add "* -EOPNOTSUPP: should never occur", then, that ok with you?
no, also explain in which conditions it is returned
something like: * -EOPNOTSUPP: if the memslot is not writable (should never occour)
- */
+int cmpxchg_guest_abs_with_key(struct kvm *kvm, gpa_t gpa, int len,
__uint128_t *old_p, __uint128_t new,u8 access_key)+{
- gfn_t gfn = gpa >> PAGE_SHIFT;
- struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
exchange the above two lines (reverse christmas tree)
Is this a hard requirement? Since there is a dependency. If I do the initialization further down, the order wouldn't actually change.
ahhhhh right, I had missed that
keep it as it is, of course
[...]
I really dislike repeating the same code 5 times, but I guess there was no other way?
I could use the function called by cmpxchg_user_key directly, but Heiko won't agree to that. A macro would work too, of course, not sure if I prefer that tho.
ok so there is no other way, let's keep it as it is
[...]
To me it feels like KVM_S390_MEMOP_R_NO_XCHG is api surface and should be referenced here. cmpxchg_guest_abs_with_key isn't mem op specific (of course that's the only thing it is currently used for).
fair enough
if (copy_to_user(old_p, &old.raw[off_in_quad], mop->size))r = -EFAULT;}