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Bug #8623

IMMU_CONTIG_PADDR is broken for cookies with more than one page

Added by Hans Rosenfeld over 3 years ago. Updated over 3 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Hans Rosenfeld
Category:
kernel
Start date:
2017-09-07
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:
needs-triage
Gerrit CR:

Description

The macro IMMU_CONTIG_PADDR() is used to check whether a physical address would be contiguously following the physical memory block described by a cookie. Yet the macro doesn't look at the number of pages in a cookie, so whenever a cookie already has 2 pages it will return false even if the physical address is contiguous.

This leads to the use of a unnecessarily high number of cookies, and in the worst case may trigger #8622.

#1

Updated by Hans Rosenfeld over 3 years ago

Webrev: https://grumpf.hope-2000.org/illumos-8622-8623-8625/

The fix was tested on a system with IOMMU enabled. As expected the number of used cookies went down drastically as contiguous physical addresses were now correctly detected as such.

This change has been in illumos-joyent since around June.

#2

Updated by Electric Monk over 3 years ago

  • Status changed from New to Closed
  • % Done changed from 0 to 100

git commit 2cedd8f0ecbd2b29bf0aac72bb8b7413b0326938

commit  2cedd8f0ecbd2b29bf0aac72bb8b7413b0326938
Author: Hans Rosenfeld <hans.rosenfeld@joyent.com>
Date:   2017-09-20T18:35:31.000Z

    8622 panic in PTE_set_all()
    8623 IMMU_CONTIG_PADDR is broken for cookies with more than one page
    8625 nvme causes bad free panic in IOMMU
    Reviewed by: Robert Mustacchi <rm@joyent.com>
    Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
    Approved by: Garrett D'Amore <garrett@damore.org>

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