[RFC 00/12] arm64: Add support for TLBI domains

[Marc Zyngier]

Hi Kristina,

On Thu, 01 Oct 2026 12:06:43 +0100,
Kristina Martšenko <kristina.martsenko at arm.com> wrote:

[...]

>   * It's also possible to use TLBI domains to limit a KVM guest's TLB
>     invalidations to CPUs where the guest has run. I'll try to include that in
>     the next version. This series only disables domains for guests.

My take on this is that just like MPAM, it makes little sense to
expose this to guests. As long as the L0 hypervisor has the means that
to scope TLBIs to the relevant domains (subset of CPUs to start with,
but hopefully SMMUs eventually), we're good.

>   * With this series a long-running process may eventually run on all CPUs and
>     just issue broadcast TLBIs. It may be worth periodically reducing the set
>     of CPUs but it's not clear when.

I had a think about that some time ago, and thought that you were sure
to be sub-optimal when the number of CPUs you have run on is greater
than the number of threads in your process.

But I'm sure there are better heuristics! ;-)

Thanks,

	M.

-- 
Jazz isn't dead. It just smells funny.