Re: [Qemu-devel] [QEMU-PPC] [PATCH V3 05/10] target/ppc: Add patb_entry to sPAPRMachineState

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

On Thu, 2017-02-23 at 14:50 +1100, David Gibson wrote:
> On Mon, Feb 20, 2017 at 03:04:33PM +1100, Suraj Jitindar Singh wrote:
> > 
> > ISA v3.00 adds the idea of a partition table which is used to store
> > the
> > address translation details for all partitions on the system. The
> > partition
> > table consists of double word entries indexed by partition id where
> > the second
> > double word contains the location of the process table in guest
> > memory. The
> > process table is registered by the guest via a h-call.
> > 
> > We need somewhere to store the address of the process table so we
> > add an entry
> > to the sPAPRMachineState struct called patb_entry to represent the
> > second
> > doubleword of a single partition table entry corresponding to the
> > current
> > guest. We need to store this value so we know if the guest is using
> > radix or
> > hash translation and the location of the corresponding process
> > table in guest
> > memory. Since we only have a single guest per qemu instance, we
> > only need one
> > entry.
> > 
> > Since the partition table is technically a hypervisor resource we
> > require that
> > access to it is abstracted by the virtual hypervisor through the
> > calls
> > [set/get]_patbe(). Currently the value of the entry is never set
> > (and thus
> You've removed set_patb() as requested, but haven't updated the
> commit
> message here.

Wooops... :)
> 
> > 
> > defaults to 0 indicating hash), but it will be required to both
> > implement
> > POWER9 kvm support and tcg radix support.
> > 
> > We also add this field to be migrated as part of the
> > sPAPRMachineState as we
> > will need it on the receiving side as the guest will never tell us
> > this
> > information again and we need it to perform translation.
> > 
> > Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> This looks fine, but will need some reworking to rebase on my
> hpt-cleanup patch series.  That might even obsolete the new vhc call.
> 
Yeah the plan is to make this series apply cleanly on your hpt-cleanup.
> > 
> > 
> > ---
> > 
> > V2->V3:
> > - Only add patbe to migration stream if non-zero
> > ---
> >  hw/ppc/spapr.c         | 29 +++++++++++++++++++++++++++++
> >  include/hw/ppc/spapr.h |  1 +
> >  target/ppc/cpu.h       |  1 +
> >  3 files changed, 31 insertions(+)
> > 
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index e465d7a..2fbf193 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1018,6 +1018,13 @@ static void
> > emulate_spapr_hypercall(PPCVirtualHypervisor *vhyp,
> >      }
> >  }
> >  
> > +static uint64_t spapr_get_patbe(PPCVirtualHypervisor *vhyp)
> > +{
> > +    sPAPRMachineState *spapr = SPAPR_MACHINE(vhyp);
> > +
> > +    return spapr->patb_entry;
> > +}
> > +
> >  #define HPTE(_table, _i)   (void *)(((uint64_t *)(_table)) + ((_i)
> > * 2))
> >  #define HPTE_VALID(_hpte)  (tswap64(*((uint64_t *)(_hpte))) &
> > HPTE64_V_VALID)
> >  #define HPTE_DIRTY(_hpte)  (tswap64(*((uint64_t *)(_hpte))) &
> > HPTE64_V_HPTE_DIRTY)
> > @@ -1141,6 +1148,8 @@ static void ppc_spapr_reset(void)
> >      /* Check for unknown sysbus devices */
> >      foreach_dynamic_sysbus_device(find_unknown_sysbus_device,
> > NULL);
> >  
> > +    spapr->patb_entry = 0;
> > +
> >      /* Allocate and/or reset the hash page table */
> >      spapr_reallocate_hpt(spapr,
> >                           spapr_hpt_shift_for_ramsize(machine-
> > >maxram_size),
> > @@ -1327,6 +1336,24 @@ static const VMStateDescription
> > vmstate_spapr_ov5_cas = {
> >      },
> >  };
> >  
> > +static bool spapr_patb_entry_needed(void *opaque)
> > +{
> > +    sPAPRMachineState *spapr = opaque;
> > +
> > +    return !!spapr->patb_entry;
> > +}
> > +
> > +static const VMStateDescription vmstate_spapr_patb_entry = {
> > +    .name = "spapr_patb_entry",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .needed = spapr_patb_entry_needed,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT64(patb_entry, sPAPRMachineState),
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> >  static const VMStateDescription vmstate_spapr = {
> >      .name = "spapr",
> >      .version_id = 3,
> > @@ -1344,6 +1371,7 @@ static const VMStateDescription vmstate_spapr
> > = {
> >      },
> >      .subsections = (const VMStateDescription*[]) {
> >          &vmstate_spapr_ov5_cas,
> > +        &vmstate_spapr_patb_entry,
> >          NULL
> >      }
> >  };
> > @@ -2733,6 +2761,7 @@ static void
> > spapr_machine_class_init(ObjectClass *oc, void *data)
> >      nc->nmi_monitor_handler = spapr_nmi;
> >      smc->phb_placement = spapr_phb_placement;
> >      vhc->hypercall = emulate_spapr_hypercall;
> > +    vhc->get_patbe = spapr_get_patbe;
> >  }
> >  
> >  static const TypeInfo spapr_machine_info = {
> > diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> > index a2d8964..c6a929a 100644
> > --- a/include/hw/ppc/spapr.h
> > +++ b/include/hw/ppc/spapr.h
> > @@ -63,6 +63,7 @@ struct sPAPRMachineState {
> >  
> >      void *htab;
> >      uint32_t htab_shift;
> > +    uint64_t patb_entry; /* Process tbl registed in
> > H_REGISTER_PROCESS_TABLE */
> >      hwaddr rma_size;
> >      int vrma_adjust;
> >      ssize_t rtas_size;
> > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
> > index 425e79d..684d632 100644
> > --- a/target/ppc/cpu.h
> > +++ b/target/ppc/cpu.h
> > @@ -1218,6 +1218,7 @@ struct PPCVirtualHypervisor {
> >  struct PPCVirtualHypervisorClass {
> >      InterfaceClass parent;
> >      void (*hypercall)(PPCVirtualHypervisor *vhyp, PowerPCCPU
> > *cpu);
> > +    uint64_t (*get_patbe)(PPCVirtualHypervisor *vhyp);
> >  };
> >  
> >  #define TYPE_PPC_VIRTUAL_HYPERVISOR "ppc-virtual-hypervisor"