On Thu, May 18, 2023 at 05:08:16PM -0700, Dave Hansen wrote: > On 5/18/23 17:04, alison.schofield@xxxxxxxxx wrote: > > The initial use case is the ACPI driver that needs to extend > > SRAT defined proximity domains to an entire CXL CFMWS Window[1]. > > Dumb question time: Why didn't the SRAT just cover this sucker in the > first place? Are we fixing up a BIOS bug or is there a legitimate > reason that the SRAT didn't cover it up front? > > There is no requirement that the BIOS describe (in the SRAT) all the HPA assigned to a CFMWS Window. The HPA range may not actually map to any memory at boot time. It can be persistent capacity or may be there to enable hot-plug. IIUC BIOS can pick and choose and define volatile regions wherever it pleases. So, no we're not fixing up a BIOS bug, nor doing a BIOS sanity check.
