Re: git: 6171e026be11 - main - bhyve: add support for MTRR
Date: Tue, 18 Jan 2022 15:19:15 UTC
On 1/14/22 3:42 AM, Emmanuel Vadot wrote: > The branch main has been updated by manu: > > URL: https://cgit.FreeBSD.org/src/commit/?id=6171e026be11824495cebe8baf559af673a8e533 > > commit 6171e026be11824495cebe8baf559af673a8e533 > Author: Corvin Köhne <CorvinK@beckhoff.com> > AuthorDate: 2022-01-14 09:58:48 +0000 > Commit: Emmanuel Vadot <manu@FreeBSD.org> > CommitDate: 2022-01-14 11:41:44 +0000 > > bhyve: add support for MTRR > > Some guests or driver might depend on MTRR to work properly. E.g. the > nvidia gpu driver won't work without MTRR. > > Reviewed by: markj > MFC after: 2 weeks > Sponsored by: Beckhoff Automation GmbH & Co. KG > Differential Revision: https://reviews.freebsd.org/D33333 So this doesn't look like actual emulation, but more like a dummy version? That is, the values aren't initialized to the "normal" state (WB for guest RAM, UC- for everything else), and the state isn't enforced in any way (I think the only sane way to actually implement these would be to use MTRR to set PAT values in EPT entries if EPT even supports PAT). Perhaps this mostly doesn't matter since we don't directly map BARs in EPT anyway? (Though perhaps for passthrough we might in which case you'd want to honor these settings in those?) -- John Baldwin