Re: [PATCH v2 8/8] hw/arm/virt: add ITS support in virt GIC

[shashi.mallela@linaro.org]

On Mon, 2021-04-19 at 13:46 +0100, Peter Maydell wrote:
> On Thu, 1 Apr 2021 at 03:42, Shashi Mallela <
> shashi.mallela@linaro.org> wrote:
> > Included creation of ITS as part of virt platform GIC
> > initialization.This Emulated ITS model now co-exists with kvm
> > ITS and is enabled in absence of kvm irq kernel support in a
> > platform.
> > 
> > Signed-off-by: Shashi Mallela <shashi.mallela@linaro.org>
> > ---
> >  hw/arm/virt.c        | 10 ++++++++--
> >  target/arm/kvm_arm.h |  4 ++--
> >  2 files changed, 10 insertions(+), 4 deletions(-)
> > 
> > diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> > index aa2bbd14e0..77cf2db90f 100644
> > --- a/hw/arm/virt.c
> > +++ b/hw/arm/virt.c
> > @@ -622,7 +622,7 @@ static void create_v2m(VirtMachineState *vms)
> >      vms->msi_controller = VIRT_MSI_CTRL_GICV2M;
> >  }
> > 
> > -static void create_gic(VirtMachineState *vms)
> > +static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
> >  {
> >      MachineState *ms = MACHINE(vms);
> >      /* We create a standalone GIC */
> > @@ -656,6 +656,12 @@ static void create_gic(VirtMachineState *vms)
> >                               nb_redist_regions);
> >          qdev_prop_set_uint32(vms->gic, "redist-region-count[0]",
> > redist0_count);
> > 
> > +        if (!kvm_irqchip_in_kernel()) {
> > +            object_property_set_link(OBJECT(vms->gic), "sysmem",
> > OBJECT(mem),
> > +                                     &error_fatal);
> > +            qdev_prop_set_bit(vms->gic, "has-lpi", true);
> > +        }
> > +
> >          if (nb_redist_regions == 2) {
> >              uint32_t redist1_capacity =
> >                      vms->memmap[VIRT_HIGH_GIC_REDIST2].size /
> > GICV3_REDIST_SIZE;
> > @@ -2039,7 +2045,7 @@ static void machvirt_init(MachineState
> > *machine)
> > 
> >      virt_flash_fdt(vms, sysmem, secure_sysmem ?: sysmem);
> > 
> > -    create_gic(vms);
> > +    create_gic(vms, sysmem);
> > 
> >      virt_cpu_post_init(vms, sysmem);
> > 
> > diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
> > index 34f8daa377..0613454975 100644
> > --- a/target/arm/kvm_arm.h
> > +++ b/target/arm/kvm_arm.h
> > @@ -525,8 +525,8 @@ static inline const char *its_class_name(void)
> >          /* KVM implementation requires this capability */
> >          return kvm_direct_msi_enabled() ? "arm-its-kvm" : NULL;
> >      } else {
> > -        /* Software emulation is not implemented yet */
> > -        return NULL;
> > +        /* Software emulation based model */
> > +        return "arm-gicv3-its";
> >      }
> >  }
> 
> This is OK as far as it goes, but I think we need to add the
> versioned-machine support so that only "virt-6.1" and later get the
> new ITS, and "virt-6.0" behave the same way (ie no ITS) as they did
> in older QEMU versions.
> 
> Have added versioned machine support to enable new ITS only for
> versions 6.1 and above
> thanks
> -- PMM