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Differential D56518

vm: Add flags for unprotected allocations
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Authored by sarah.walker2_arm.com on Mon, Apr 20, 1:16 PM.
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kib
alc
markj
andrew
Summary

Unprotected allocations are intended to be accessible outside of the current
VM on systems such as Arm CCA.

Sponsored by: Arm Ltd

Diff Detail

Repository
rG FreeBSD src repository
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Build Status
Buildable 72433
Build 69316: arc lint + arc unit

Event Timeline

sarah.walker2_arm.com created this revision.Mon, Apr 20, 1:16 PM
Herald added a subscriber: imp. · View Herald TranscriptMon, Apr 20, 1:16 PM
sarah.walker2_arm.com requested review of this revision.Mon, Apr 20, 1:16 PM
Harbormaster completed remote builds in B72357: Diff 175892.Mon, Apr 20, 1:16 PM
sarah.walker2_arm.com added a child revision: D56519: busdma_bounce: Allocate bounce buffers as unprotected.Mon, Apr 20, 1:17 PM
andrew added reviewers: kib, alc, markj, andrew.Mon, Apr 20, 1:23 PM
markj added a comment.Mon, Apr 20, 2:28 PM

Why can't this flag be stored in the machine-dependent fields of the page, i.e., in some spare field of struct md_page?

sarah.walker2_arm.com updated this revision to Diff 175985.Tue, Apr 21, 1:59 PM

Remove PG_UNPROTECTED flag

Harbormaster completed remote builds in B72418: Diff 175985.Tue, Apr 21, 1:59 PM
sarah.walker2_arm.com added a comment.Tue, Apr 21, 2:00 PM
In D56518#1293767, @markj wrote:

Why can't this flag be stored in the machine-dependent fields of the page, i.e., in some spare field of struct md_page?

I'm assuming you were referring to PG_UNPROTECTED? On further examination it's not required, so the latest change removes it.

markj added inline comments.Tue, Apr 21, 2:53 PM
sys/vm/vm_page.h
537 ↗(On Diff #175985)

What's the purpose of VM_ALLOC_UNPROTECTED? vm_page_alloc_* don't do anything with it.

sarah.walker2_arm.com updated this revision to Diff 176091.Wed, Apr 22, 10:19 AM

Remove VM_ALLOC_UNPROTECTED.

Harbormaster completed remote builds in B72433: Diff 176091.Wed, Apr 22, 10:19 AM
sarah.walker2_arm.com added inline comments.Wed, Apr 22, 10:20 AM
sys/vm/vm_page.h
537 ↗(On Diff #175985)

You are correct, VM_ALLOC_UNPROTECTED no long serves a purpose. Removed.

markj accepted this revision.Wed, Apr 22, 1:05 PM

This seems fine, something similar will be needed on amd64 for, e.g., AMD SVE.

This revision is now accepted and ready to land.Wed, Apr 22, 1:05 PM
alc added a comment.Thu, Apr 23, 5:07 AM

Just out of curiosity, where are the pmap changes?

andrew added a comment.Thu, Apr 23, 7:05 AM
In D56518#1295709, @alc wrote:

Just out of curiosity, where are the pmap changes?

They are part of D56520. To mark the mapping as unprotected we set a bit in the physical address. The firmware tells us which bit to set on boot.

My understanding is Intel and AMD have similar schemes on their equivalent to Arm CCA.

Revision Contents
Changeset List

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sys/
sys/
1 line
vm/
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23 lines

Diff 176091

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sys/sys/malloc.h

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sys/vm/pmap.h

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sys/vm/vm_kern.c

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