Subject: Re: [PATCH 2/3] KVM: PPC: Fix vmx/vsx mixup in mmio emulation

From: Fabiano Rosas <[email-masked]>
Date: Mon, 27 Dec 2021 14:28:28 -0300

Nicholas Piggin <[email-masked]> writes:

> Excerpts from Fabiano Rosas's message of December 24, 2021 7:15 am:
>> The MMIO emulation code for vector instructions is duplicated between
>> VSX and VMX. When emulating VMX we should check the VMX copy size
>> instead of the VSX one.
>> 
>> Fixes: acc9eb9305fe ("KVM: PPC: Reimplement LOAD_VMX/STORE_VMX instruction ...")
>> Signed-off-by: Fabiano Rosas <[email-masked]>
>
> Good catch. AFAIKS handle_vmx_store needs the same treatment? If you
> agree then

Half the bug now, half the bug next year... haha I'll send a v2.

aside:
All this duplication is kind of annoying. I'm looking into what it would
take to have quadword instruction emulation here as well (Alexey caught
a bug with syskaller) and the code would be really similar. I see that
x86 has a more generic implementation that maybe we could take advantage
of. See "f78146b0f923 (KVM: Fix page-crossing MMIO)"