Re: [XEN PATCH] hvmloader: Enable MMIO and I/O decode, after all resource allocation

[Jan Beulich <jbeulich@xxxxxxxx>]

On 07.04.2020 10:25, Roger Pau Monné wrote:
> IMO forcefully disabling decodings (and enabling them afterwards if
> already enabled) and leaving bus mastering as-is would be better.

Limiting this to the "already enabled" case may not be enough:
Devices needed for guest booting may need them to be enabled
even if prior to BAR assignment they were turned off. That's
what a BIOS would typically do, too. I've seen quite a few
BIOS setups actually where one could chose whether the BIOS
would do so just for what it recognized as boot devices, or
for all of them.

Jan