Hi David, On Wed, Jul 20, 2022 at 08:41:48PM +0200, David Hildenbrand wrote: > > + while (len) { > > + size_t block = MIN(len, sizeof(tmp)); > > + > > + qemu_guest_getrandom_nofail(tmp, block); > > + for (size_t i = 0; i < block; ++i) { > > + cpu_stb_data_ra(env, wrap_address(env, *buf_reg), > > tmp[i], ra); > > + *buf_reg = deposit64(*buf_reg, 0, reg_len, > > *buf_reg + 1); > > + --*len_reg; > > + } > > + len -= block; > > + } > > Yeah, that's better, although kind-off hard to read. > > We could process one guest page at a time, similar to how we handle > target/s390x/tcg/mem_helper.c:access_memset and friends nowadays. > > But I won't force you to do that ;) > > This here is good enough for now, with room for improvement regarding > efficiency. > > I did not review the doc in detail once again, maybe I get to that later > this week.
Alright, so we'll leave it be for now then and stick with this v3. The do_access_memset trick is clever, but sheesh, seems a bit overkill for here. On the real hardware, this instruction takes ~190us for every 32 byte chunk, so there's basically no way that we can possibly be worse than that. :) Jason