Re: [PATCH V3 6/6] libxl: Allocate MMIO params for GPIO device and update DT

[Oleksandr <olekstysh@xxxxxxxxx>]

On 04.08.22 10:01, Viresh Kumar wrote:

Hello Viresh


> This patch allocates Virtio MMIO params (IRQ and memory region) and pass
> them to the backend, also update Guest device-tree based on Virtio GPIO
> DT bindings [1].
>
> [1] 
> https://www.kernel.org/doc/Documentation/devicetree/bindings/gpio/gpio-virtio.yaml
>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
>   tools/libs/light/libxl_arm.c | 47 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 47 insertions(+)
>
> diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
> index 08a1499c9523..14b95087f027 100644
> --- a/tools/libs/light/libxl_arm.c
> +++ b/tools/libs/light/libxl_arm.c
> @@ -121,6 +121,15 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
>               return rc;
>       }
>   
> +    for (i = 0; i < d_config->num_gpios; i++) {
> +        libxl_device_gpio *gpio = &d_config->gpios[i];
> +
> +    int rc = alloc_virtio_mmio_params(gc, &gpio->base, &gpio->irq,
> +            &virtio_mmio_base, &virtio_mmio_irq);
> +    if (rc)
> +        return rc;
> +    }
> +
>       /*
>        * Every virtio-mmio device uses one emulated SPI. If Virtio devices are
>        * present, make sure that we allocate enough SPIs for them.
> @@ -974,6 +983,38 @@ static int make_virtio_mmio_node_i2c(libxl__gc *gc, void 
> *fdt, uint64_t base,
>       return fdt_end_node(fdt);
>   }
>   
> +static int make_virtio_mmio_node_gpio(libxl__gc *gc, void *fdt, uint64_t base,
> +                                      uint32_t irq)
> +{
> +    int res;
> +
> +    res = make_virtio_mmio_node_common(gc, fdt, base, irq);
> +    if (res) return res;
> +
> +    res = fdt_begin_node(fdt, "gpio");
> +    if (res) return res;
> +
> +    res = fdt_property_compat(gc, fdt, 1, "virtio,device29");
> +    if (res) return res;
> +
> +    res = fdt_property(fdt, "gpio-controller", NULL, 0);
> +    if (res) return res;
> +
> +    res = fdt_property_cell(fdt, "#gpio-cells", 2);
> +    if (res) return res;
> +
> +    res = fdt_property(fdt, "interrupt-controller", NULL, 0);
> +    if (res) return res;
> +
> +    res = fdt_property_cell(fdt, "#interrupt-cells", 2);
> +    if (res) return res;
> +
> +    res = fdt_end_node(fdt);
> +    if (res) return res;
> +
> +    return fdt_end_node(fdt);
> +}
> +
>   static const struct arch_info *get_arch_info(libxl__gc *gc,
>                                                const struct xc_dom_image *dom)
>   {
> @@ -1305,6 +1346,12 @@ static int libxl__prepare_dtb(libxl__gc *gc, 
> libxl_domain_config *d_config,
>               FDT( make_virtio_mmio_node_i2c(gc, fdt, i2c->base, i2c->irq) );
>           }
>   
> +        for (i = 0; i < d_config->num_gpios; i++) {
> +            libxl_device_gpio *gpio = &d_config->gpios[i];
> +
> +            FDT( make_virtio_mmio_node_gpio(gc, fdt, gpio->base, gpio->irq) );
> +        }
> +
>           if (pfdt)
>               FDT( copy_partial_fdt(gc, fdt, pfdt) );
I think that patch needs to be updated taking into the account 
suggestions provided for two previous patches (of course, if you agree 
with them).
If so, the make_virtio_mmio_node_gpio() should gain "uint32_t 
backend_domid" argument, etc. And we need to make sure that 
make_xen_iommu_node() will be called for virtio gpio.

Something like the diff on top of current patch below (not tested):

diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
index 9bd8d49f3c..54756b3dd5 100644
--- a/tools/libs/light/libxl_arm.c
+++ b/tools/libs/light/libxl_arm.c
@@ -986,11 +986,11 @@ static int make_virtio_mmio_node_i2c(libxl__gc 
*gc, void *fdt, uint64_t base,
 }

 static int make_virtio_mmio_node_gpio(libxl__gc *gc, void *fdt, 
uint64_t base,
-                                      uint32_t irq)
+                                      uint32_t irq, uint32_t backend_domid)
 {
     int res;

-    res = make_virtio_mmio_node_common(gc, fdt, base, irq);
+    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid);
     if (res) return res;

     res = fdt_begin_node(fdt, "gpio");
@@ -1350,8 +1350,11 @@ next_resize:

         for (i = 0; i < d_config->num_gpios; i++) {
             libxl_device_gpio *gpio = &d_config->gpios[i];
+            if (gpio->backend_domid != LIBXL_TOOLSTACK_DOMID)
+                iommu_needed = true;

-            FDT( make_virtio_mmio_node_gpio(gc, fdt, gpio->base, 
gpio->irq) );
+            FDT( make_virtio_mmio_node_gpio(gc, fdt, gpio->base, gpio->irq,
+ gpio->backend_domid) );
         }

         /*

Other changes look good.


>   
--
Regards,

Oleksandr Tyshchenko