RE: [PATCH v4 5/7] hw/arm/virt: Add an SMMU_IO_LEN macro

[Shameerali Kolothum Thodi via]

> -----Original Message-----
> From: Jonathan Cameron <jonathan.came...@huawei.com>
> Sent: Monday, June 16, 2025 12:02 PM
> To: Shameerali Kolothum Thodi
> <shameerali.kolothum.th...@huawei.com>; Linuxarm
> <linux...@huawei.com>
> Cc: qemu-...@nongnu.org; qemu-devel@nongnu.org;
> eric.au...@redhat.com; peter.mayd...@linaro.org; j...@nvidia.com;
> nicol...@nvidia.com; ddut...@redhat.com; berra...@redhat.com;
> imamm...@redhat.com; nath...@nvidia.com; mo...@nvidia.com;
> smost...@google.com; Wangzhou (B) <wangzh...@hisilicon.com>;
> jiangkunkun <jiangkun...@huawei.com>; Jonathan Cameron
> <jonathan.came...@huawei.com>; zhangfei....@linaro.org
> Subject: Re: [PATCH v4 5/7] hw/arm/virt: Add an SMMU_IO_LEN macro
> 
> On Fri, 13 Jun 2025 15:44:47 +0100
> Shameer Kolothum <shameerali.kolothum.th...@huawei.com> wrote:
> 
> > From: Nicolin Chen <nicol...@nvidia.com>
> >
> > This is useful as the subsequent support for new SMMUv3 dev will also
> > use the same.
> >
> > Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
> > Reviewed-by: Donald Dutile <ddut...@redhat.com>
> > Reviewed-by: Eric Auger <eric.au...@redhat.com>
> > Tested-by: Nathan Chen <nath...@nvidia.com>
> > Signed-off-by: Shameer Kolothum
> <shameerali.kolothum.th...@huawei.com>
> > ---
> >  hw/arm/virt.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> > index 71b923f786..eeace4754d 100644
> > --- a/hw/arm/virt.c
> > +++ b/hw/arm/virt.c
> > @@ -146,6 +146,9 @@ static void arm_virt_compat_set(MachineClass
> *mc)
> >  #define LEGACY_RAMLIMIT_GB 255
> >  #define LEGACY_RAMLIMIT_BYTES (LEGACY_RAMLIMIT_GB * GiB)
> >
> > +/* MMIO region size for SMMUv3 */
> > +#define SMMU_IO_LEN 0x20000
> > +
> >  /* Addresses and sizes of our components.
> >   * 0..128MB is space for a flash device so we can run bootrom code such
> as UEFI.
> >   * 128MB..256MB is used for miscellaneous device I/O.
> > @@ -177,7 +180,7 @@ static const MemMapEntry base_memmap[] = {
> >      [VIRT_FW_CFG] =             { 0x09020000, 0x00000018 },
> >      [VIRT_GPIO] =               { 0x09030000, 0x00001000 },
> >      [VIRT_UART1] =              { 0x09040000, 0x00001000 },
> > -    [VIRT_SMMU] =               { 0x09050000, 0x00020000 },
> > +    [VIRT_SMMU] =               { 0x09050000, SMMU_IO_LEN },
> 
> This bit is fine.
> 
> >      [VIRT_PCDIMM_ACPI] =        { 0x09070000, MEMORY_HOTPLUG_IO_LEN
> },
> >      [VIRT_ACPI_GED] =           { 0x09080000, ACPI_GED_EVT_SEL_LEN },
> >      [VIRT_NVDIMM_ACPI] =        { 0x09090000, NVDIMM_ACPI_IO_LEN},
> > @@ -1447,7 +1450,6 @@ static void create_smmu(const
> VirtMachineState *vms,
> >      int irq =  vms->irqmap[VIRT_SMMU];
> >      int i;
> >      hwaddr base = vms->memmap[VIRT_SMMU].base;
> > -    hwaddr size = vms->memmap[VIRT_SMMU].size;
> >      DeviceState *dev;
> >
> >      if (vms->iommu != VIRT_IOMMU_SMMUV3 || !vms->iommu_phandle) {
> > @@ -1467,7 +1469,7 @@ static void create_smmu(const
> VirtMachineState *vms,
> >          sysbus_connect_irq(SYS_BUS_DEVICE(dev), i,
> >                             qdev_get_gpio_in(vms->gic, irq + i));
> >      }
> > -    create_smmuv3_dt_bindings(vms, base, size, irq);
> > +    create_smmuv3_dt_bindings(vms, base, SMMU_IO_LEN, irq);
> 
> This seems a little odd.  I guess it may make sense later, but for all other
> cases we only use the macros to define the base_memmap.
> 
> Perhaps delay this change until it is more obvious why?

Right, looking at this patch now, I think it is not necessary at the moment
to introduce this macro now. I will take another look and discard this
if it doesn't make sense.

Thanks,
Shameer