On 7/22/26 2:27 AM, Peter Xu wrote:
On Tue, Jul 21, 2026 at 03:37:53PM +1000, Gavin Shan wrote:
If Peter is fine with two variants for x86 and non-x86 architectures.
I can post (v4) for further review. That will be something like below
and let me know if there are any other improvements are needed.
I have a generic question on the "unaligned access for x86": I think the
question is about the one Michael raised here on unaligned access may break
x86 here:
https://lore.kernel.org/qemu-devel/[email protected]/
3. (theoretical concern) also on x86, unaligned accesses are
possible on guest and host, so converting an unaligned access to a
series of aligned ones can in theory break devices.
Is that a real problem we need to consider, or can we start with unified
approach and leave it for later?
I'm leaving this question to Michael.
PS: I apologize if I missed important piece of info along the way; I didn't
follow closely on the discussion on this topic in the past few weeks.
One thing to mention is, what we change should only need to affect
ram_device, AFAIU.. so most memcpy()/memmove() shouldn't be changed for any
arch when it's pure RAM.
It depends. This patch intends to fix issue [1] in the lower layer by using
the newly added accessors (qemu_ram_{copy, move}) on all directly accessible
regions including the regular (pure) RAM region. Otherwise, the newly added
accessors should be limited to ram_device regions only as you said.
[1]
https://lore.kernel.org/qemu-devel/[email protected]/
Thanks,
Gavin
