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bhyve: allocate guest memory for graphics stolen memory

Description

bhyve: allocate guest memory for graphics stolen memory

The graphics stolen memory is only GPU accessible. So, we don't have to
copy any data to it as the guest will be unable to access it anyway. We
just have to allocate and reserve some memory. That's done by adding an
E820 entry for the graphics stolen memory. The guest firmware will pick
up the E820 and reserve this range.

Note that we try to reuse the host address as Intel states that newer
Tiger Lake platforms need this [1].

[1]
https://github.com/projectacrn/acrn-hypervisor/blob/e28d6fbfdfd556ff1bc3ff330e41d4ddbaa0f897/devicemodel/hw/pci/passthrough.c#L626-L629

Reviewed by: markj
MFC after: 1 week
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D40059

Details

Provenance
corvinkAuthored on May 11 2023, 9:10 AM
Reviewer
markj
Differential Revision
D40059: bhyve: allocate guest memory for graphics stolen memory
Parents
rG4a9bf50f408e: bhyve: read out graphics stolen memory address and size
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