On Thu, Feb 23, 2023 at 2:03 AM Marc Zyngier [off-list ref] wrote:

On Thu, 23 Feb 2023 03:58:47 +0000,
Yu Zhao [off-list ref] wrote:

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On Fri, Feb 17, 2023 at 2:00 AM Marc Zyngier [off-list ref] wrote:

quoted

On Fri, 17 Feb 2023 04:21:28 +0000,
Yu Zhao [off-list ref] wrote:

quoted

On Thu, Feb 16, 2023 at 9:12 PM Yu Zhao [off-list ref] wrote:

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This patch adds kvm_arch_test_clear_young() for the vast majority of
VMs that are not pKVM and run on hardware that sets the accessed bit
in KVM page tables.

I'm really interested in how you can back this statement. 90% of the
HW I have access to is not FEAT_HWAFDB capable, either because it
predates the feature or because the feature is too buggy to be useful.

This is my expericen too -- most devices are pre v8.2.

And yet you have no issue writing the above. Puzzling.

That's best to my knowledge. Mind enlightening me?

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Do you have numbers?

Let's do a quick market survey by segment. The following only applies
to ARM CPUs:

1. Phones: none of the major Android phone vendors sell phones running
VMs; no other major Linux phone vendors.

Maybe you should have a reality check and look at what your own
employer is shipping.

Which model? I'll look it up and see how/how I missed it.

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2. Laptops: only a very limited number of Chromebooks run VMs, namely
ACRVM. No other major Linux laptop vendors.

Again, your employer disagree.

What do you mean? Sorry, I'm a little surprised here... I do know *a
lot* about Chromebooks.

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3. Desktops: no major Linux desktop vendors.

My desktop disagree (I send this from my arm64 desktop VM ).

A model number please?

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4. Embedded/IoT/Router: no major Linux vendors run VMs (Android Auto
can be a VM guest on QNX host).

This email is brought to you via a router VM on an arm64 box.

More details?

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5. Cloud: this is where the vast majority VMs come from. Among the
vendors available to the general public, Ampere is the biggest player.
Here [1] is a list of its customers. The A-bit works well even on its
EVT products (Neoverse cores).

Just the phone stuff dwarfs the number of cloud hosts.

Please point me to something that I can work on so that I wouldn't
sound so ignorant next time.