On 10/7/22 09:50, Peter Maydell wrote:
On Fri, 7 Oct 2022 at 17:45, Richard Henderson
<richard.hender...@linaro.org> wrote:
On 10/7/22 06:47, Peter Maydell wrote:
Are there definitely no code paths where we might try to do
a page table walk with the iothread already locked ?
I'll double-check, but another possibility is to simply perform the atomic
operation on
the low 32-bits, where both AF and DB are located. Another trick I learned
from x86...
Doesn't that cause a problem where we don't detect that some other
CPU wrote to the high 32 bits of the descriptor ? We're supposed to
be using those high 32 bits, not the ones we have in hand...
Hmm, yes. Which now makes me wonder if the x86 case is in fact buggy...
If we do need the iothread lock, we could do it the way that
io_readx() does, I guess, where we track whether we needed to
lock it or not.
yes.
r~
