bhyve: enlarge 64-bit PCI MMIO hole to 1 TiB
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Authored by tsoome on May 6 2026, 10:23 AM.

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bhyve

Summary

Default 32 GiB hole is insufficient for modern GPUs whose BAR1 (HBM
aperture) is 128 GiB each. Four H100 SXM5 GPUs need ~512 GiB of
prefetchable 64-bit PCI MMIO. Bump to 1 TiB for headroom, covering
future hardware like H200 (192 GiB/GPU).

Assisted-By: Claude Opus 4.7 (1M context)

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Repository

rG FreeBSD src repository

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Build Status

Buildable 72843
Build 69726: arc lint + arc unit

Event Timeline

tsoome created this revision.May 6 2026, 10:23 AM

Herald added a reviewer: bhyve. · View Herald TranscriptMay 6 2026, 10:23 AM

Herald added subscribers: bcran, rgrimes, imp. · View Herald Transcript

tsoome requested review of this revision.May 6 2026, 10:23 AM

Harbormaster completed remote builds in B72843: Diff 177293.May 6 2026, 10:23 AM

Was this change motivated by this comment in PR290920 and have you tested this patch somehow yet?
If not, I think that commenter would be more than willing to test it.

Revision Contents
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usr.sbin/

bhyve/

pci_emul.c

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Diff 177293

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bhyve: enlarge 64-bit PCI MMIO hole to 1 TiBNeeds ReviewPublicActions