On Mon, Jul 19, 2021 at 11:02 AM Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> wrote: > We forward the whole PSCI function range, so it's either KVM or userspace. > If KVM manages PSCI and the guest calls an unimplemented function, that > returns directly to the guest without going to userspace. > > The concern is valid for any other range, though. If userspace enables the > HVC cap it receives function calls that at some point KVM might need to > handle itself. So we need some negotiation between user and KVM about the > specific HVC ranges that userspace can and will handle. Are we going to use KVM_CAPs for every interesting HVC range that userspace may want to trap? I wonder if a more generic interface for hypercall filtering would have merit to handle the aforementioned cases, and whatever else a VMM will want to intercept down the line. For example, x86 has the concept of 'MSR filtering', wherein userspace can specify a set of registers that it wants to intercept. Doing something similar for HVCs would avoid the need for a kernel change each time a VMM wishes to intercept a new hypercall. -- Thanks, Oliver _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
