[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-ppc] [QEMU-PPC] [PATCH 2/2] target/ppc/spapr: Add SPAPR_CAP_CC
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [QEMU-PPC] [PATCH 2/2] target/ppc/spapr: Add SPAPR_CAP_CCF_ASSIST |
Date: |
Mon, 4 Mar 2019 11:52:58 +1100 |
User-agent: |
Mutt/1.11.3 (2019-02-01) |
On Fri, Mar 01, 2019 at 03:26:45PM +1100, Suraj Jitindar Singh wrote:
> On Fri, 2019-03-01 at 14:19 +1100, Suraj Jitindar Singh wrote:
> > Introduce a new spapr_cap SPAPR_CAP_CCF_ASSIST to be used to indicate
> > the requirement for a hw-assisted version of the count cache flush
> > workaround.
> >
> > The count cache flush workaround is a software workaround which can
> > be
> > used to flush the count cache on context switch. Some revisions of
> > hardware may have a hardware accelerated flush, in which case the
> > software flush can be shortened. This cap is used to set the
> > availability of such hardware acceleration for the count cache flush
> > routine.
> >
> > The availability of such hardware acceleration is indicated by the
> > H_CPU_CHAR_BCCTR_FLUSH_ASSIST flag being set in the characteristics
> > returned from the KVM_PPC_GET_CPU_CHAR ioctl.
> >
> > Signed-off-by: Suraj Jitindar Singh <address@hidden>
> > ---
> > hw/ppc/spapr.c | 2 ++
> > hw/ppc/spapr_caps.c | 25 +++++++++++++++++++++++++
> > hw/ppc/spapr_hcall.c | 3 +++
> > include/hw/ppc/spapr.h | 5 ++++-
> > target/ppc/kvm.c | 14 ++++++++++++++
> > target/ppc/kvm_ppc.h | 6 ++++++
> > 6 files changed, 54 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 1df324379f..708e18dcdf 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -2086,6 +2086,7 @@ static const VMStateDescription vmstate_spapr =
> > {
> > &vmstate_spapr_cap_nested_kvm_hv,
> > &vmstate_spapr_dtb,
> > &vmstate_spapr_cap_large_decr,
> > + &vmstate_spapr_cap_ccf_assist,
> > NULL
> > }
> > };
> > @@ -4319,6 +4320,7 @@ static void
> > spapr_machine_class_init(ObjectClass *oc, void *data)
> > smc->default_caps.caps[SPAPR_CAP_HPT_MAXPAGESIZE] = 16; /* 64kiB
> > */
> > smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
> > smc->default_caps.caps[SPAPR_CAP_LARGE_DECREMENTER] =
> > SPAPR_CAP_ON;
> > + smc->default_caps.caps[SPAPR_CAP_CCF_ASSIST] = SPAPR_CAP_OFF;
> > spapr_caps_add_properties(smc, &error_abort);
> > smc->irq = &spapr_irq_xics;
> > smc->dr_phb_enabled = true;
> > diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
> > index 74a48a423a..f03f2f64e7 100644
> > --- a/hw/ppc/spapr_caps.c
> > +++ b/hw/ppc/spapr_caps.c
> > @@ -436,6 +436,21 @@ static void
> > cap_large_decr_cpu_apply(sPAPRMachineState *spapr,
> > ppc_store_lpcr(cpu, lpcr);
> > }
> >
> > +static void cap_ccf_assist_apply(sPAPRMachineState *spapr, uint8_t
> > val,
> > + Error **errp)
> > +{
> > + uint8_t kvm_val = kvmppc_get_cap_count_cache_flush_assist();
> > +
> > + if (tcg_enabled() && val) {
> > + /* TODO - for now only allow broken for TCG */
> > + error_setg(errp,
> > +"Requested count cache flush assist capability level not supported
> > by tcg, try cap-ccf-assist=off");
> > + } else if (kvm_enabled() && (val > kvm_val)) {
> > + error_setg(errp,
> > +"Requested count cache flush assist capability level not supported
> > by kvm, try cap-ccf-assist=off");
> > + }
>
> Actually, this should probably be non-fatal if the count cache flush
> routine isn't enabled
Since the new cap values aren't enabled by default, I've applied
anyway. You can make this error non-fatal in a followup.
--
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
signature.asc
Description: PGP signature
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-ppc] [QEMU-PPC] [PATCH 2/2] target/ppc/spapr: Add SPAPR_CAP_CCF_ASSIST,
David Gibson <=