On 24/12/25 19:34, Manos Pitsidianakis wrote:
On Wed, Dec 24, 2025 at 5:14 PM Philippe Mathieu-Daudé <[email protected]> wrote:Commit 500131154d6 ("exec.c: Add new address_space_ld*/st* functions") added a new API to fix a shortcoming of the ld/st*_phys() API, which does blind bus access, not reporting failure (and it also allow to provide transaction attributes). Later commit 42874d3a8c6 ("Switch non-CPU callers from ld/st*_phys to address_space_ld/st*") automatically converted the legacy uses to the new API, not precising transaction attributes (MEMTXATTRS_UNSPECIFIED) and ignoring the transation result (passing NULL pointer as MemTxResult). While this is a faithful replacement, without any logical change, we later realized better is to not use MEMTXATTRS_UNSPECIFIED or NULL MemTxResult, and adapt each call site on a pair basis, looking at the device model datasheet to do the correct behavior (which is unlikely to ignore transaction failures). Since this is quite some work, we defer that to device model maintainers. Meanwhile we introduce a definition, to allow a target which removed all legacy API call to prohibit further legacy API uses, named "TARGET_NOT_USING_LEGACY_LDST_PHYS_API".Personally the negation (i.e. TARGET_USING_LEGACY_LDST_PHYS_API) would make more sense since you're opting-in an API but that must be more complex to introduce I guess?
Not much more complex, this was the previous approach (allow all then opt out): https://lore.kernel.org/qemu-devel/[email protected]/ But Pierrick suggested the less aggressive approach, opting in, disturbing maintainers a bit less. In term of code churn I expect the same lines of code amount to change.
In any case: Reviewed-by: Manos Pitsidianakis <[email protected]>
Thanks!
