Scott Wood wrote: > On Fri, 17 Sep 2010 09:58:41 +0800 > "tiejun.chen" <tiejun.c...@windriver.com> wrote: > >> Scott Wood wrote: >>> The guest OS *is* the same as native Linux, as far as TLB handling is >>> concerned. >> Looks you means the TLB exception handler should be same between the native >> and >> the guest OS. Right? > > Yes.
I don't think so. The HY should assist the guest OS on MMU since I already point the guest OS have no authority to create a real TLB directly as I previously said. > >> Here I assume we're talking about e500mc since as far as I know for Freescale >> only e500mc is designed to support virtual machine based on ISA 2.0.6. > > Yes, though there's nothing preventing virtualization on cores without > category E.HV (KVM supports this) -- it's just slower. Absolutely. > >> I also know all TLB exceptions can direct to the guest OS when we enable >> EPCR[DTLBGS|ITLBGS|DSIGS|ISIGS]. But some TLB instructions (i.e. tlbwe )are >> the >> privileged instructions. So the guest OS always trap into the hypervisor and >> then the hypervisor should complete the real action with appropriate physical >> address. > > Yes, of course. But that's not the point. I was just using it as a > convenient example because that's what I've recently done ELF loading > with... There's no reason U-Boot couldn't do the same if its ELF > loader were updated to support device trees. Currently U-Boot loads > bootwrapperless uImages to physical address zero. I never doubt the U-boot can do this for uImage. But I think we're always talking about vmlinux, a bare Image. Here you already assume so many conditions for vmlinux before we were discussing. Such as bootwrapperlee uImage, its ELF loader can update/support dtb, the HY... I think this is just why I say we cannot boot vmlinux based on common boot loader if only change entry point of vmlinux. > > And FWIW, we have run setups where our hv loads Linux to true > physical zero (with the hv living elsewhere), not just guest physical. That's true. The HY should be allowed to access any address. Best Regards Tiejun > > -Scott > > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
