On 22/08/2019 21:57, Rich Persaud wrote: >> On Aug 22, 2019, at 09:51, Andrew Cooper <andrew.coop...@citrix.com> wrote: >> >>> On 22/08/2019 03:06, Johnson, Ethan wrote: >>> >>> For HVM, obviously anything that can't be virtualized natively by the >>> hardware needs to be emulated by Xen/QEMU (since the guest kernel isn't >>> expected to be cooperative to issue PV hypercalls instead); but I would >>> expect emulation to be limited to the relatively small subset of the ISA >>> that VMX/SVM can't natively virtualize. Yet I see that x86_emulate.c >>> supports emulating just about everything. Under what circumstances does >>> Xen actually need to put all that emulation code to use? >> Introspection, as I said earlier, which is potentially any instruction. > Could introspection-specific emulation code be disabled via KConfig?
Not really. At the point something has trapped for emulation, we must complete it in a manner consistent with the x86 architecture, or the guest will crash. If you don't want emulation from introspection, don't start introspecting in the first place, at which point guest actions won't trap in the first place. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
