Using edu driver under arm virt machine

[nobodynobody]

Hi everyone,

I'm new to this mailing list.

I'm trying to develop a custom qemu pci drivers using the edu drivers (hw/misc/edu.c) as a base.

I've done this before on x86_64 architecture without problem.

I have try to do the same on an arm VM running with virt machine.

the virt machine description:

https://www.qemu.org/docs/master/system/arm/virt.html

says that it support pci/pcie devices.

So I code a dummy pci device, usind edu drivers as a template.

I added the -device edu, to the command line of qemu-system-arm

and launched my vm.

the device appears with I do lspci:

# lspci -n

00:01.0 Class 0200: 1af4:1000

00:00.0 Class 0600: 1b36:0008

00:02.0 Class 00ff: 1234:11e8   <--- it's the edu drivers

it's memory seems mapped:

cat /sys/devices/platform/4010000000.pcie/pci0000:00/0000:00:02.0/resource

0x0000000010000000 0x00000000100fffff 0x0000000000040200

0x0000000000000000 0x0000000000000000 0x0000000000000000

0x0000000000000000 0x0000000000000000 0x0000000000000000

0x0000000000000000 0x0000000000000000 0x0000000000000000

so I try to put a breakpoint in edu_mmio_read & edu_mmio_write function, and map this zone , and write to it, as I did before on x86_64 vm.

But the breakpoint is never hit..????

I try to put breakpoint on other places in qemu, it works perfectly..

If I read to the mmio mapped memory with some generic tool like pcimem,

it returns 0xffffff ??

normally the address at offset 0 in mmio mapped memory of edu drivers should return 0x10000edu.

as the drivers source code shows:

   switch (addr) {

    case 0x00:

        val = 0x010000edu;

        break;

When I do the same on x86_64, it works perfectly, and the 0x10000edu value is returned as exepected...

I try everything possible, but impossible to communicate with the edu drivers via mmio mapped memory on arm architecture on virt machine...????!!!!

So my question is:

is the edu pci drivers usable on arm virt machine?

or does it need some specific qemu or kernel architecture...

I'm out of ideas... If someone can help me :)

best regards