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Re: [Qemu-ppc] [PATCH v4 5/8] spapr: Consolidate cpu init code into a ro
Re: [Qemu-ppc] [PATCH v4 5/8] spapr: Consolidate cpu init code into a routine
Tue, 16 Jun 2015 15:40:05 +1000
On Mon, Jun 15, 2015 at 10:15:09AM +0200, Thomas Huth wrote:
> On Mon, 15 Jun 2015 16:59:08 +1000
> David Gibson <address@hidden> wrote:
> > On Fri, Jun 05, 2015 at 09:55:55AM +0530, Bharata B Rao wrote:
> > > Factor out bits of sPAPR specific CPU initialization code into
> > > a separate routine so that it can be called from CPU hotplug
> > > path too.
> > >
> > > While at this, use MSR_EP define instead of using 6 directly.
> > Don't do this please. MSR[EP] is an obsolete flag from 601. The
> > MSR[IP] flag that we're controlling here just happened to re-use the
> > same bit position, so using the existing MSR_EP define is misleading.
> Actually, I had the same discussion with Bharata already some weeks ago:
> > A symbolic name is good, but you should create a new one for MSR[IP]
> > instead.
> ... and I had to realize that IP = EP. IP likely stands for "interrupt
> prefix" (I guess), and EP simply means "exception prefix", so just two
> words for the same meaning. It's just the "on 601" comment in QEMU that
> is completely misleading. So IMHO it should be fine to keep the
> "MSR_EP" here (and maybe update the comment in cpu.h with a separate
I don't entirely agree. Yes EP and IP have related functions - it's
pretty common in ppc history that when an MSR bit is re-used it's for
something similar (for example IS/IR). But MSR[IP] is still a
different name from MSR[EP], and I don't know if the semantics are
identical, though I'm sure they're similar.
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
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[Qemu-ppc] [PATCH v4 2/8] spapr: Support ibm, lrdr-capacity device tree property, Bharata B Rao, 2015/06/05
[Qemu-ppc] [PATCH v4 3/8] cpus: Add a macro to walk CPUs in reverse, Bharata B Rao, 2015/06/05
[Qemu-ppc] [PATCH v4 5/8] spapr: Consolidate cpu init code into a routine, Bharata B Rao, 2015/06/05
[Qemu-ppc] [PATCH v4 4/8] spapr: Reorganize CPU dt generation code, Bharata B Rao, 2015/06/05
[Qemu-ppc] [PATCH v4 6/8] ppc: Update cpu_model in MachineState, Bharata B Rao, 2015/06/05
[Qemu-ppc] [PATCH v4 7/8] xics_kvm: Don't enable KVM_CAP_IRQ_XICS if already enabled, Bharata B Rao, 2015/06/05
- Re: [Qemu-ppc] [PATCH v4 1/8] spapr: Consider max_cpus during xics initialization, (continued)