Page Comparison

Attendees

• Mike
• Arnd
• Massami
• Shashi
• Alex
• Bill
• Mathieu
• Matt  (Arm)
• Stefano (Xilinx)
• Mark
• Joakim
• Jean-Phillip
• Illias
• Bill
• Randy
• Sumit
• Bogdan (NXP)
• Srivasa Srivatsa (QC)
• Ruchika
• Souvick
• Diana (NXP)
• Ed Doxat (Arm)
• Pratik
• Vincent

Goals

• Get a view of the  engineering support available to work on Stratos

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Update on the demo progress

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Introduction to cheri and some thoughts on its relevance to Stratos

Workign with Arm : been running 10 years

Steffano : cherification is adding  capabilities : Joakim yes

Arnd : not sensible to try with Linux, it cant work with t 128 bits

Lots of questions about what happens to pointers across security boundaries (sycalls into kernels, pointers between device/driver, moving to secure world etc).

Please ping Joakim - slides LINKBeen working on if you have questions

The current state of  VirtIO-MMU / Limited Memory Sharing

Slides:

Arnd: discussed 3 different approaches - do they all suck? Which to start prototyping?

Option 1: host manages shared memory, use swiotlb to force use of shared memory

Option 2: guest uses IOMMU, signals pages meant for access, no copying, expensive transactions updating iommu?

Option 3: new virtquue design, shared memory part of queue (inline).

Steffano: can we increase the size of the queue? Arnd: it involves changing the binary layout of the queue

Steffano: had to increase ring size for 9pfs implementation - needed to go to 2Mb (up from 512K)

Arnd: having large queues risks cache thrashing.

Alex: Does swiotlb always imply copying Arnd: yes

Stefano: what about virtio managing page allocation?

Alex: sees the complexities with existing devices, talked about video - size it for

Stefano: what about expanding option 3 but allowing bigger sizes queus appropriate to the device?

Arnd: Option 3 has s simplicity, but offers a allocation per device.

Srivista: our implementation currently is closer to option 1

What is the development platform ?

Action items