On 02.07.2010, at 21:10, Scott Wood wrote: > On Fri, 2 Jul 2010 20:47:44 +0200 > Alexander Graf <agraf@xxxxxxx> wrote: > >> >> On 02.07.2010, at 19:59, Hollis Blanchard wrote: >> >>> [Resending...] >>> >>> Please reconcile this with >>> http://www.linux-kvm.org/page/PowerPC_Hypercall_ABI, which has been >>> discussed in the (admittedly closed) Power.org embedded hypervisor >>> working group. Bear in mind that other hypervisors are already >>> implementing the documented ABI, so if you have concerns, you should >>> probably raise them with that audience... >> >> We can not use sc with LV=1 because that would break the KVM in >> something else case which is KVM's strong point on PPC. > > The current proposal involves the hypervisor specifying the hcall opcode > sequence in the device tree -- to allow either "sc 1" or "sc 0 plus > magic GPR" depending on whether you've got the hardware hypervisor > feature (hereafter HHV). Ah right, so you can still trap a hypercall with HHV. Makes sense. > > With HHV, "sc 0 plus magic GPR" just doesn't work, since it won't trap > to the hypervisor. "sc 1 plus magic GPR" might be problematic on some > non-HHV implementations, especially if you *do* have HHV but the > non-HHV hypervisor is running as an HHV guest. Yes, that's why I need sc 0 plus magic GPR in r0 and r3 - to accomodate for all the non-HHV cases. And it would be clever to have a way to expose the same functionality when we do use the HHV features. So, is that draft available anywhere? The wiki page Hollis pointed to is very vague. Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
