Re: [PATCH for-4.20 v3 2/4] x86/HVM: correct read/write split at page boundaries

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Jan 23, 2025 at 11:31:19AM +0100, Jan Beulich wrote:
> The MMIO cache is intended to have one entry used per independent memory
> access that an insn does. This, in particular, is supposed to be
> ignoring any page boundary crossing. Therefore when looking up a cache
> entry, the access'es starting (linear) address is relevant, not the one
> possibly advanced past a page boundary.
> 
> In order for the same offset-into-buffer variable to be usable in
> hvmemul_phys_mmio_access() for both the caller's buffer and the cache
> entry's it is further necessary to have the un-adjusted caller buffer
> passed into there.
> 
> Fixes: 2d527ba310dc ("x86/hvm: split all linear reads and writes at page 
> boundary")
> Reported-by: Manuel Andreas <manuel.andreas@xxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Thanks, Roger.