Re: [Qemu-devel] [Qemu-ppc] [PATCH 3/5] target-ppc: Synchronize more SPRs to KVM using ONE_REG interface

[David Gibson]

On Wed, Jan 23, 2013 at 11:52:54AM -0600, Scott Wood wrote:
> On 01/22/2013 11:04:59 PM, David Gibson wrote:
> >diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> >index 2f4f068..e84b993 100644
> >--- a/target-ppc/kvm.c
> >+++ b/target-ppc/kvm.c
> >@@ -60,7 +60,7 @@ static int cap_booke_sregs;
> > static int cap_ppc_smt;
> > static int cap_ppc_rma;
> > static int cap_spapr_tce;
> >-static int cap_hior;
> >+static int cap_one_reg;
> >
> > /* XXX We have a race condition where we actually have a level
> >triggered
> >  *     interrupt, but the infrastructure can't expose that yet,
> >so the guest
> >@@ -89,7 +89,11 @@ int kvm_arch_init(KVMState *s)
> >     cap_ppc_smt = kvm_check_extension(s, KVM_CAP_PPC_SMT);
> >     cap_ppc_rma = kvm_check_extension(s, KVM_CAP_PPC_RMA);
> >     cap_spapr_tce = kvm_check_extension(s, KVM_CAP_SPAPR_TCE);
> >-    cap_hior = kvm_check_extension(s, KVM_CAP_PPC_HIOR);
> >+    /* This capability is misnamed - it was introduced with the
> >+     * KVM_SET_ONE_REG ioctl(), which at the time only supported the
> >+     * HIOR.  We don't want a different capability for every register
> >+     * the interface can support though. */
> >+    cap_one_reg = kvm_check_extension(s, KVM_CAP_PPC_HIOR);
> 
> So what happens when we want to use onereg for booke, which doesn't
> have KVM_CAP_PPC_HIOR?  Into what variable would we put a check for
> KVM_CAP_ONE_REG?

Drat, good point.  There is no KVM_CAP_ONE_REG, that's the problem.  I
guess I'll have to leave cap_hior as it is, and just not have a
capability check.

> IMHO this should stay as cap_hior and merge the above comment with
> the comment where you check cap_hior, regarding not all registers
> necessarily being supported.

I'm not sure quite what you mean by this.

-- 
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_!
http://www.ozlabs.org/~dgibson

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