Re: [PATCH 0/4] X86: Alias isa-bios area and clean up

[Michael S. Tsirkin]

On Mon, Apr 22, 2024 at 10:06:21PM +0200, Bernhard Beschow wrote:
> This series changes the "isa-bios" MemoryRegion to be an alias rather than a
> copy in the pflash case. This fixes issuing pflash commands in the isa-bios
> region which matches real hardware and which some real-world legacy bioses I'm
> running rely on. Furthermore, aliasing in the isa-bios area is already the
> current behavior in the bios (a.k.a. ROM) case, so this series consolidates
> behavior.
> 
> The consolidateion results in duplicate code which is resolved in the second
> half (patches 3 and 4) in this series.
> 
> Question: AFAIU, patch 2 changes the behavior for SEV-enabled guests since the
> isa-bios area is now encrypted. Does this need compat machinery or is it a
> bugfix?

When in doubt, do a compat thing.

> Testing done:
> * `make check` with qemu-system-x86_64 (QEMU 8.2.2) installed. All tests
>   including migration tests pass.
> * `make check-avocado`
> 
> Best regards,
> Bernhard
> 
> Bernhard Beschow (4):
>   hw/i386/pc_sysfw: Remove unused parameter from pc_isa_bios_init()
>   hw/i386/pc_sysfw: Alias rather than copy isa-bios region
>   hw/i386/x86: Eliminate two if statements in x86_bios_rom_init()
>   hw/i386: Consolidate isa-bios creation
> 
>  include/hw/i386/x86.h |  2 ++
>  hw/i386/pc_sysfw.c    | 38 ++++----------------------------------
>  hw/i386/x86.c         | 35 +++++++++++++++++++----------------
>  3 files changed, 25 insertions(+), 50 deletions(-)
> 
> -- 
> 2.44.0
>