[Qemu-devel] [PATCH] hw/arm/virt: "bus-range"/end is off by one

[Qemu-devel] [PATCH] hw/arm/virt: "bus-range"/end is off by one

[Laszlo Ersek]

According to "PCI Bus Binding to IEEE Std 1275-1994", 3.1.2. Bus-specific
Properties for Bus Nodes, the second integer in "bus-range" is an
inclusive limit.

This seems to be consistent with several *.dtsi files in the kernel tree,
where examples like

  bus-range = <0 0>;

are visible.

In addition, the loop in gen_pci_parse_map_cfg_windows()
[drivers/pci/host/pci-host-generic.c] uses "bus_range->end" as an
inclusive limit.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---

Notes:
    Applies on top of target-arm.next.

 hw/arm/virt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index a2a5c96..ee77093 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -693,7 +693,8 @@ static void create_pcie(const VirtBoardInfo *vbi, qemu_irq *pic,
     qemu_fdt_setprop_string(vbi->fdt, nodename, "device_type", "pci");
     qemu_fdt_setprop_cell(vbi->fdt, nodename, "#address-cells", 3);
     qemu_fdt_setprop_cell(vbi->fdt, nodename, "#size-cells", 2);
-    qemu_fdt_setprop_cells(vbi->fdt, nodename, "bus-range", 0, nr_pcie_buses);
+    qemu_fdt_setprop_cells(vbi->fdt, nodename, "bus-range", 0,
+                           nr_pcie_buses - 1);
 
     qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",
                                  2, base_ecam, 2, size_ecam);
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH] hw/arm/virt: "bus-range"/end is off by one

[Wei Huang]

On 02/12/2015 12:50 PM, Laszlo Ersek wrote:
> According to "PCI Bus Binding to IEEE Std 1275-1994", 3.1.2. Bus-specific
> Properties for Bus Nodes, the second integer in "bus-range" is an
> inclusive limit.
> 
> This seems to be consistent with several *.dtsi files in the kernel tree,
> where examples like
> 
>   bus-range = <0 0>;
> 
> are visible.
> 
> In addition, the loop in gen_pci_parse_map_cfg_windows()
> [drivers/pci/host/pci-host-generic.c] uses "bus_range->end" as an
> inclusive limit.
> 
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>     Applies on top of target-arm.next.
> 
>  hw/arm/virt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index a2a5c96..ee77093 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -693,7 +693,8 @@ static void create_pcie(const VirtBoardInfo *vbi, qemu_irq *pic,
>      qemu_fdt_setprop_string(vbi->fdt, nodename, "device_type", "pci");
>      qemu_fdt_setprop_cell(vbi->fdt, nodename, "#address-cells", 3);
>      qemu_fdt_setprop_cell(vbi->fdt, nodename, "#size-cells", 2);
> -    qemu_fdt_setprop_cells(vbi->fdt, nodename, "bus-range", 0, nr_pcie_buses);
> +    qemu_fdt_setprop_cells(vbi->fdt, nodename, "bus-range", 0,
> +                           nr_pcie_buses - 1);
>  
>      qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",
>                                   2, base_ecam, 2, size_ecam);
> 

I instrumented a guest VM (of/of_pci.c) to print out the bus range.
Without this patch, bus_range->[start, end]=[0, 16]. So this patch makes
sense to me:

Reviewed-by: Wei Huang <wei@redhat.com>

Thanks,
-Wei

Re: [Qemu-devel] [PATCH] hw/arm/virt: "bus-range"/end is off by one

[Alexander Graf]

On 12.02.15 19:50, Laszlo Ersek wrote:
> According to "PCI Bus Binding to IEEE Std 1275-1994", 3.1.2. Bus-specific
> Properties for Bus Nodes, the second integer in "bus-range" is an
> inclusive limit.
> 
> This seems to be consistent with several *.dtsi files in the kernel tree,
> where examples like
> 
>   bus-range = <0 0>;
> 
> are visible.
> 
> In addition, the loop in gen_pci_parse_map_cfg_windows()
> [drivers/pci/host/pci-host-generic.c] uses "bus_range->end" as an
> inclusive limit.
> 
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Nice catch!

Reviewed-by: Alexander Graf <agraf@suse.de>


Alex

Re: [Qemu-devel] [PATCH] hw/arm/virt: "bus-range"/end is off by one

[Peter Maydell]

On 13 February 2015 at 01:12, Alexander Graf <agraf@suse.de> wrote:
>
>
> On 12.02.15 19:50, Laszlo Ersek wrote:
>> According to "PCI Bus Binding to IEEE Std 1275-1994", 3.1.2. Bus-specific
>> Properties for Bus Nodes, the second integer in "bus-range" is an
>> inclusive limit.
>>
>> This seems to be consistent with several *.dtsi files in the kernel tree,
>> where examples like
>>
>>   bus-range = <0 0>;
>>
>> are visible.
>>
>> In addition, the loop in gen_pci_parse_map_cfg_windows()
>> [drivers/pci/host/pci-host-generic.c] uses "bus_range->end" as an
>> inclusive limit.
>>
>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>
> Nice catch!
>
> Reviewed-by: Alexander Graf <agraf@suse.de>

Since I haven't pushed the pci patches yet I'll just squash
this fix in to them.

thanks
-- PMM