Re: [RFC PATCH] docs/about/deprecated: Deprecate 32-bit host systems

Daniel P. Berrangé <berrange(a)redhat.com&gt; writes: > On Mon, Jan 30, 2023 at 11:47:02AM +0000, Peter Maydell wrote: >> On Mon, 30 Jan 2023 at 11:44, Thomas Huth <thuth(a)redhat.com&gt; wrote: >>> >>> Testing 32-bit host OS support takes a lot of precious time during the QEMU >>> contiguous integration tests, and considering that many OS vendors stopped >>> shipping 32-bit variants of their OS distributions and most hardware from >>> the past >10 years is capable of 64-bit >> >> True for x86, not necessarily true for other architectures. >> Are you proposing to deprecate x86 32-bit, or all 32-bit? >> I'm not entirely sure about whether we're yet at a point where >> I'd want to deprecate-and-drop 32-bit arm host support. > > Do we have a feeling on which aspects of 32-bit cause us the support > burden ? The boring stuff like compiler errors from mismatched integer > sizes is mostly quick & easy to detect simply through a cross compile. > > I vaguely recall someone mentioned problems with atomic ops in the past, > or was it 128-bit ints, caused implications for the codebase ? Atomic operations on > TARGET_BIT_SIZE and cputlb when TCG_OVERSIZED_GUEST is set. Also the core TCG code and a bunch of the backends have TARGET_LONG_BITS > TCG_TARGET_REG_BITS ifdefs peppered throughout.