On Thu, 23 Feb 2023 03:58:47 +0000, Yu Zhao <yuzhao@xxxxxxxxxx> wrote: > > On Fri, Feb 17, 2023 at 2:00 AM Marc Zyngier <maz@xxxxxxxxxx> wrote: > > > > On Fri, 17 Feb 2023 04:21:28 +0000, > > Yu Zhao <yuzhao@xxxxxxxxxx> wrote: > > > > > > On Thu, Feb 16, 2023 at 9:12 PM Yu Zhao <yuzhao@xxxxxxxxxx> wrote: > > > > > > > > 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. > > > 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. > 2. Laptops: only a very limited number of Chromebooks run VMs, namely > ACRVM. No other major Linux laptop vendors. Again, your employer disagree. > 3. Desktops: no major Linux desktop vendors. My desktop disagree (I send this from my arm64 desktop VM ). > 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. > 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. Hopefully your patches are better than your market analysis... M. -- Without deviation from the norm, progress is not possible.
