Virtualization - Oct 2021 - [PATCH v5 16/16] x86/tdx: Add cmdline option to force use of ioremap_host_shared

> Presumably bios code is in arch/x86 and drivers/acpi, right?
> Up to 200 calls the majority of which is likely private ...
Yes.
> I don't have better ideas but the current setup will just
> result in people making their guests vulnerable whenever they
> want to allow device pass-through.

Yes that's true. For current TDX our target is virtual devices only. But 
if pass through usage will be really wide spread we may need to revisit.


-Andi

On Mon, Oct 11, 2021 at 10:35:18AM -0700, Andi Kleen
wrote:
> 
> > Presumably bios code is in arch/x86 and drivers/acpi, right?
> > Up to 200 calls the majority of which is likely private ...
> 
> Yes.
> 
> > I don't have better ideas but the current setup will just
> > result in people making their guests vulnerable whenever they
> > want to allow device pass-through.
> 
> 
> Yes that's true. For current TDX our target is virtual devices only.
But if
> pass through usage will be really wide spread we may need to revisit.
> 
> 
> -Andi
I mean ... it's already wide spread. If we support it with TDX
it will be used with TDX. If we don't then I guess it won't,
exposing this kind of limitation in a userspace visible way isn't great
though. I guess it boils down to the fact that
ioremap_host_shared is just not a great interface, users simply
have no idea whether a given driver uses ioremap.

-- 
MST