Re: [kvm-devel] [PATCH] kvm_show_code for ROM code

[Avi K. <av...@qu...>]

Jan Kiszka wrote:
> Userland-located ROM memory is not available via kvm->physical_memory +
> guest_address. To let kvm_show_code also dump useful information when
> some problem in ROM (BIOS...) occurs, this patch first tries to obtain
> the memory content via the mmio_read callback - maybe not 100% clean,
> but works at least for the QEMU use case. If the callback complains
> about the given address, we then fall back to RAM access.
>
>   

kvm->physical_memory is actually broken, since nothing guarantees a 1:1 
(+offset) mapping.

Why not use ->mmio_read() all the time?  Sure it overloads the 
definition of mmio_read(), but worse things have happened.

-- 
Any sufficiently difficult bug is indistinguishable from a feature.