Mappings with mode VM_MEMATTR_DEVICE and VM_MEMATTR_DEVICE_NP are unprotected
Imported busdma buffers in protected memory are always bounced
If EARLY_PRINTK is in use, the UART physical address must be in the unprotected address space

Diff Detail

Repository

rG FreeBSD src repository

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Unit

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Build Status

Buildable 72465
Build 69348: arc lint + arc unit

Event Timeline

sarah.walker2_arm.com created this revision.Apr 23 2026, 10:30 AM

Herald added a reviewer: andrew. · View Herald TranscriptApr 23 2026, 10:30 AM

Herald added a reviewer: andrew. · View Herald Transcript

Herald added a reviewer: manu. · View Herald Transcript

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sarah.walker2_arm.com requested review of this revision.Apr 23 2026, 10:30 AM

Harbormaster completed remote builds in B72465: Diff 176244.Apr 23 2026, 10:30 AM

sarah.walker2_arm.com added a parent revision: D56598: arm64: Add RSI detection for CCA.Apr 23 2026, 10:30 AM

sarah.walker2_arm.com added a child revision: D56600: arm64: Load SOCDEV_PA as a literal rather than an immediate.

sarah.walker2_arm.com mentioned this in D56520: arm64: Add CCA guest support.Apr 23 2026, 10:31 AM

andrew added reviewers: alc, markj, kib.Apr 23 2026, 3:49 PM

andrew added inline comments.

sys/arm64/arm64/efirt_machdep.c
232	Needs to be on `pa` not page table entry
sys/arm64/arm64/pmap.c
4223
5438–5439	This should be applied to `pa` as it may be wrong under FEAT_LPA2
5757	Is this correct when entering a large page, e.g. when `psind == 2` a level 2 block will be created

Address review comments

Harbormaster completed remote builds in B72488: Diff 176274.Apr 23 2026, 5:26 PM

andrew accepted this revision.May 5 2026, 2:02 PM

This revision is now accepted and ready to land.May 5 2026, 2:02 PM

Closed by commit rG56abdbc5f709: arm64: VM/PMAP changes for CCA guest support. · Explain WhyMay 12 2026, 4:56 PM

This revision was automatically updated to reflect the committed changes.

andrew added a commit: rG56abdbc5f709: arm64: VM/PMAP changes for CCA guest support.

I recently updated my Microsoft Dev Kit, and because of this change I'm seeing:

bus_dmamem_alloc failed to align memory properly.

The warning stems from an allocation by the nvme driver:

KDB: stack backtrace:
db_trace_self() at db_trace_self
db_trace_self_wrapper() at db_trace_self_wrapper+0x44
bounce_bus_dmamem_alloc() at bounce_bus_dmamem_alloc+0x258
nvme_ctrlr_start() at nvme_ctrlr_start+0xbc8
nvme_ctrlr_start_config_hook() at nvme_ctrlr_start_config_hook+0x5ec
run_interrupt_driven_config_hooks() at run_interrupt_driven_config_hooks+0x94
boot_run_interrupt_driven_config_hooks() at boot_run_interrupt_driven_config_hooks+0x30
mi_startup() at mi_startup+0x1ec
virtdone() at virtdone+0x70

An added printf reports:

vaddr: 0xffffa000847d3f40, paddr: 1047d3f40, alignment: 1000

In this case, the misalignment appears to be harmless because page size alignment isn't actually needed.

In D56599#1364175, @alc wrote:
I recently updated my Microsoft Dev Kit, and because of this change I'm seeing:
bus_dmamem_alloc failed to align memory properly.

Could you test https://reviews.freebsd.org/D59476 please?

jtranoleary_google.com mentioned this in D60384: gve: align dma buffers to requested boundary.Oct 6 2026, 9:29 PM