[Stratos-dev] Re: [PATCH V3 4/6] libxl: arm: Split make_virtio_mmio_node()

On 04.08.22 10:01, Viresh Kumar wrote:

Hello Viresh

make_virtio_mmio_node() creates the DT node for simple MMIO devices currently, i.e. the ones that don't require any additional properties.

In order to allow using it for other complex device types, split the functionality into two, one where the fdt node isn't closed and the other one to create a simple DT node.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org

tools/libs/light/libxl_arm.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c index 2f64b9f0ebee..6a8c4d042bd9 100644 --- a/tools/libs/light/libxl_arm.c +++ b/tools/libs/light/libxl_arm.c @@ -900,9 +900,8 @@ static int make_xen_iommu_node(libxl__gc *gc, void *fdt) return 0; } -static int make_virtio_mmio_node(libxl__gc *gc, void *fdt,

•                             uint64_t base, uint32_t irq,
  

•                             uint32_t backend_domid)
  

+static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base,

•                                    uint32_t irq)
  

  { int res; gic_interrupt intr;

@@ -922,7 +921,15 @@ static int make_virtio_mmio_node(libxl__gc *gc, void *fdt, res = fdt_property_interrupts(gc, fdt, &intr, 1); if (res) return res;

• res = fdt_property(fdt, "dma-coherent", NULL, 0);

• return fdt_property(fdt, "dma-coherent", NULL, 0);

+}

+static int make_virtio_mmio_node_simple(libxl__gc *gc, void *fdt, uint64_t base,

•                                    uint32_t irq, uint32_t backend_domid)
  

+{

• int res;
• res = make_virtio_mmio_node_common(gc, fdt, base, irq); if (res) return res;

if (backend_domid != LIBXL_TOOLSTACK_DOMID) { @@ -935,10 +942,7 @@ static int make_virtio_mmio_node(libxl__gc *gc, void *fdt, if (res) return res; }

• res = fdt_end_node(fdt);
• if (res) return res;
• return 0;

• return fdt_end_node(fdt); }

static const struct arch_info *get_arch_info(libxl__gc *gc, @@ -1261,8 +1265,8 @@ static int libxl__prepare_dtb(libxl__gc *gc, libxl_domain_config *d_config, iommu_created = true; }

•            FDT( make_virtio_mmio_node(gc, fdt, disk->base, disk->irq,
  

•                                       disk->backend_domid) );
  

•            FDT( make_virtio_mmio_node_simple(gc, fdt, disk->base,
  

•                                        disk->irq, disk->backend_domid) );
          }
      }
  

[I failed to find a better place where to make a comment]

I think that the following chunk should be also moved to make_virtio_mmio_node_common() since it is not a virtio disk specific action, this "iommus" property pointing to "xen,grant-dma" IOMMU node is used to inform a guest that restricted memory access using Xen grant mappings needs to be enabled for the virtio device if it's backend is going to run in a non hardware domain, which I assume also applies for virtio i2c, etc.

if (backend_domid != LIBXL_TOOLSTACK_DOMID) {         uint32_t iommus_prop[2];

iommus_prop[0] = cpu_to_fdt32(GUEST_PHANDLE_IOMMU);         iommus_prop[1] = cpu_to_fdt32(backend_domid);

res = fdt_property(fdt, "iommus", iommus_prop, sizeof(iommus_prop));         if (res) return res;     }

This means that "uint32_t backend_domid" should be also passed as argument to make_virtio_mmio_node_common()

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 a98cfe708b..1a6ace3d8d 100644 --- a/tools/libs/light/libxl_arm.c +++ b/tools/libs/light/libxl_arm.c @@ -900,7 +900,7 @@ static int make_xen_iommu_node(libxl__gc *gc, void *fdt)  }

static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base, -                                        uint32_t irq) +                                        uint32_t irq, uint32_t backend_domid)  {      int res;      gic_interrupt intr; @@ -920,15 +920,7 @@ static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base,      res = fdt_property_interrupts(gc, fdt, &intr, 1);      if (res) return res;

-    return fdt_property(fdt, "dma-coherent", NULL, 0); -} - -static int make_virtio_mmio_node_simple(libxl__gc *gc, void *fdt, uint64_t base, -                                        uint32_t irq, uint32_t backend_domid) -{ -    int res; - -    res = make_virtio_mmio_node_common(gc, fdt, base, irq); +    res = fdt_property(fdt, "dma-coherent", NULL, 0);      if (res) return res;

if (backend_domid != LIBXL_TOOLSTACK_DOMID) { @@ -941,6 +933,17 @@ static int make_virtio_mmio_node_simple(libxl__gc *gc, void *fdt, uint64_t base,          if (res) return res;      }

+    return res; +} + +static int make_virtio_mmio_node_simple(libxl__gc *gc, void *fdt, uint64_t base, +                                        uint32_t irq, uint32_t backend_domid) +{ +    int res; + +    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid); +    if (res) return res; +      return fdt_end_node(fdt);  }

Other changes look good.