Re: [LSF/MM/BPF TOPIC] Virtual Machine Memory Passthrough

[Zhu Yanjun <zyjzyj2000@gmail.com>]

On Tue, Feb 21, 2023 at 12:32 AM Pasha Tatashin
<pasha.tatashin@soleen.com> wrote:
>
> Hello,
>
> As a part of an ongoing work of replacing some containerized work load
> with virtual machines within Google, I have worked on making the
> memory translations faster.
>
> I would like to propose the following topic for this year's LSF/MM/BPF:
>
> Discuss  a set of techniques that can improve the guest performance,
> memory footprint overhead, observability, and manageability of virtual
> machines by hypervirtualizing the guest memory to the extreme. The end
> goal is to allow very lightweight virtual machines to be closer in
> performance to the containers.
>
> The following items are going to be discussed in this topic:
> - Reducing the cost of SLAT page table translations.

Intel's implementation of SLAT, known as Extended Page Table (EPT),
was introduced in the Nehalem microarchitecture found in certain Core
i7, Core i5, and Core i3 processors.
ARM's virtualization extensions support SLAT, known as Stage-2
page-tables provided by a Stage-2 MMU. The guest uses the Stage-1 MMU.
Support was added as optional in the ARMv7ve architecture and is also
supported in the ARMv8 (32-bit and 64-bit) architectures.
I am interested in this. Hope we have a better solution to reduce the
cost of SLAT.

> - Reducing the memory footprint overhead.
> - Reducing the memory management overhead.
> - Increasing the observability of guest memory.
>