Zenbleed

jtk · July 2023

This could be a problem you care about. Zenbleed:

We now know that basic operations like strlen, memcpy and strcmp will use the vector registers - so we can effectively spy on those operations happening anywhere on the system! It doesn’t matter if they’re happening in other virtual machines, sandboxes, containers, processes, whatever!

linveo · July 2023

The blog post did a great job explaining what the problem is even to someone like me that does not work on low level programming. This is very interesting stuff.

yoursunny · July 2023

We now know that basic operations like strlen, memcpy and strcmp will use the vector registers - so we can effectively spy on those operations happening anywhere on the system! It doesn’t matter if they’re happening in other virtual machines, sandboxes, containers, processes, whatever!

This works because the register file is shared by everything on the same physical core. In fact, two hyperthreads even share the same physical register file.

Mentally strong provider always provisions dedicated cores, so that Zenbleed cannot affect across customers.

ZuckZwing · July 2023

@yoursunny said:
Mentally strong provider always provisions dedicated cores, so that Zenbleed cannot affect across customers.

Mentally strong customers always use Atom and Pentium, so that Zenbleed cannot affect them at all.

Neoon · July 2023

@yoursunny said:

We now know that basic operations like strlen, memcpy and strcmp will use the vector registers - so we can effectively spy on those operations happening anywhere on the system! It doesn’t matter if they’re happening in other virtual machines, sandboxes, containers, processes, whatever!

This works because the register file is shared by everything on the same physical core. In fact, two hyperthreads even share the same physical register file.

Mentally strong provider always provisions dedicated cores, so that Zenbleed cannot affect across customers.

Even if you have dedicated cores, does not mean they got pinned.

skorous · July 2023

Some of us need to be able to do floating-point operations though.

hornet · July 2023

@yoursunny said:

We now know that basic operations like strlen, memcpy and strcmp will use the vector registers - so we can effectively spy on those operations happening anywhere on the system! It doesn’t matter if they’re happening in other virtual machines, sandboxes, containers, processes, whatever!

This works because the register file is shared by everything on the same physical core. In fact, two hyperthreads even share the same physical register file.

Mentally strong provider always provisions dedicated cores, so that Zenbleed cannot affect across customers.

haha

Zenbleed

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