Re: [Qemu-devel] BUG: Re: [PATCH v3 11/14] ioport: Switch dispatching to memory core layer

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Ok. So.

What broke is...
I could try explaining but backtraces are lot better :)

Shortly - virtio_pci_config_ops.endianness was ignored before (was bad but
we had a workaround in spapr_io_ops), now it works so double swap happens
and everything gets broken.

If we talk about VGA (in powerpc, it is all about powerpc), I guess
memory_region_iorange_write() will go through mr->ops->old_portio branch
and won't do any byte swapping (so spapr_io_ops will do the job), so we are
fine here. I do not understand yet why it works on mac99 though, too late
here :)

h_logical_store is a hypercall for system firmware to do cache inhibited
read/write.


This is with the patch applied (git checkout  b40acf9):


#0  virtqueue_init (vq=0x11014ac0) at
/home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio.c:90
#1  0x0000000010371f28 in virtio_queue_set_addr (vdev=0x11019dd0, n=0x0,
addr=0xd0fb0000000)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio.c:662
#2  0x00000000102027f0 in virtio_ioport_write (opaque=0x11019580, addr=0x8,
val=0xd0fb0000)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio-pci.c:278
#3  0x0000000010202f08 in virtio_pci_config_write (opaque=0x11019580,
addr=0x8, val=0xd0fb0000, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio-pci.c:416
#4  0x000000001037e220 in memory_region_write_accessor (opaque=0x11019c78,
addr=0x8, value=0x1fffff0edc00,
    size=0x4, shift=0x0, mask=0xffffffff) at
/home/alexey/pcipassthru/qemu-impreza/memory.c:364
#5  0x000000001037e36c in access_with_adjusted_size (addr=0x8,
value=0x1fffff0edc00, size=0x4,
    access_size_min=0x1, access_size_max=0x4, access=
    @0x1069df40: 0x1037e164 <memory_region_write_accessor>, opaque=0x11019c78)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:396
#6  0x0000000010380b5c in memory_region_dispatch_write (mr=0x11019c78,
addr=0x8, data=0xd0fb0000, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:905
#7  0x0000000010383fa4 in io_mem_write (mr=0x11019c78, addr=0x8,
val=0xfbd0, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:1608
#8  0x00000000102e2fdc in address_space_rw (as=0x10ef4350
<address_space_io>, addr=0x48,
    buf=0x1fffff0edde0 "", len=0x4, is_write=0x1) at
/home/alexey/pcipassthru/qemu-impreza/exec.c:1918
#9  0x00000000102e33c8 in address_space_write (as=0x10ef4350
<address_space_io>, addr=0x48,
    buf=0x1fffff0edde0 "", len=0x4) at
/home/alexey/pcipassthru/qemu-impreza/exec.c:1969
#10 0x0000000010375754 in cpu_outl (addr=0x48, val=0xfbd0)
    at /home/alexey/pcipassthru/qemu-impreza/ioport.c:309
#11 0x0000000010358240 in spapr_io_write (opaque=0x11016a00, addr=0x48,
data=0xfbd0, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/hw/ppc/spapr_pci.c:468
#12 0x000000001037e220 in memory_region_write_accessor (opaque=0x110191f8,
addr=0x48, value=0x1fffff0ee060,
    size=0x4, shift=0x0, mask=0xffffffff) at
/home/alexey/pcipassthru/qemu-impreza/memory.c:364
#13 0x000000001037e36c in access_with_adjusted_size (addr=0x48,
value=0x1fffff0ee060, size=0x4,
    access_size_min=0x1, access_size_max=0x4, access=
    @0x1069df40: 0x1037e164 <memory_region_write_accessor>, opaque=0x110191f8)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:396
#14 0x0000000010380b5c in memory_region_dispatch_write (mr=0x110191f8,
addr=0x48, data=0xfbd0, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:905
#15 0x0000000010383fa4 in io_mem_write (mr=0x110191f8, addr=0x48,
val=0xd0fb0000, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:1608
#16 0x00000000102e47ac in stl_phys_internal (addr=0x10080000048,
val=0xd0fb0000, endian=
    DEVICE_NATIVE_ENDIAN) at /home/alexey/pcipassthru/qemu-impreza/exec.c:2420
#17 0x00000000102e48a8 in stl_phys (addr=0x10080000048, val=0xd0fb0000)
    at /home/alexey/pcipassthru/qemu-impreza/exec.c:2442
#18 0x0000000010354f1c in h_logical_store (cpu=0x1fffff0f0010,
spapr=0x10fe9510, opcode=0x40,
    args=0x1ffffffd0030) at
/home/alexey/pcipassthru/qemu-impreza/hw/ppc/spapr_hcall.c:570



This is without this patch (i.e. git checkout  b40acf9^ ):

#0  virtqueue_init (vq=0x11014ac0) at
/home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio.c:90
#1  0x00000000103720e4 in virtio_queue_set_addr (vdev=0x11019dd0, n=0x0,
addr=0xffe2000)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio.c:662
#2  0x00000000102027f0 in virtio_ioport_write (opaque=0x11019580, addr=0x8,
val=0xffe2)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio-pci.c:278
#3  0x0000000010202f08 in virtio_pci_config_write (opaque=0x11019580,
addr=0x8, val=0xffe2, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/hw/virtio/virtio-pci.c:416
#4  0x000000001037dca8 in memory_region_write_accessor (opaque=0x11019c78,
addr=0x8, value=0x1fffff0edca8,
    size=0x4, shift=0x0, mask=0xffffffff) at
/home/alexey/pcipassthru/qemu-impreza/memory.c:364
#5  0x000000001037ddf4 in access_with_adjusted_size (addr=0x8,
value=0x1fffff0edca8, size=0x4,
    access_size_min=0x1, access_size_max=0x4, access=
    @0x1069def8: 0x1037dbec <memory_region_write_accessor>, opaque=0x11019c78)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:396
#6  0x000000001037e474 in memory_region_iorange_write
(iorange=0x1ffff0005430, offset=0x8, width=0x4,
    data=0xffe2) at /home/alexey/pcipassthru/qemu-impreza/memory.c:475
#7  0x00000000103750d4 in ioport_writel_thunk (opaque=0x1ffff0005430,
addr=0x48, data=0xffe2)
    at /home/alexey/pcipassthru/qemu-impreza/ioport.c:226
#8  0x0000000010374728 in ioport_write (index=0x2, address=0x48, data=0xffe2)
    at /home/alexey/pcipassthru/qemu-impreza/ioport.c:83
#9  0x0000000010375688 in cpu_outl (addr=0x48, val=0xffe2)
    at /home/alexey/pcipassthru/qemu-impreza/ioport.c:296
#10 0x00000000103583fc in spapr_io_write (opaque=0x11016a00, addr=0x48,
data=0xffe2, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/hw/ppc/spapr_pci.c:468
#11 0x000000001037dca8 in memory_region_write_accessor (opaque=0x110191f8,
addr=0x48, value=0x1fffff0ee060,
    size=0x4, shift=0x0, mask=0xffffffff) at
/home/alexey/pcipassthru/qemu-impreza/memory.c:364
#12 0x000000001037ddf4 in access_with_adjusted_size (addr=0x48,
value=0x1fffff0ee060, size=0x4,
    access_size_min=0x1, access_size_max=0x4, access=
    @0x1069def8: 0x1037dbec <memory_region_write_accessor>, opaque=0x110191f8)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:396
#13 0x0000000010380c90 in memory_region_dispatch_write (mr=0x110191f8,
addr=0x48, data=0xffe2, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:993
#14 0x00000000103840d8 in io_mem_write (mr=0x110191f8, addr=0x48,
val=0xe2ff0000, size=0x4)
    at /home/alexey/pcipassthru/qemu-impreza/memory.c:1696
#15 0x00000000102e4968 in stl_phys_internal (addr=0x10080000048,
val=0xe2ff0000, endian=
    DEVICE_NATIVE_ENDIAN) at /home/alexey/pcipassthru/qemu-impreza/exec.c:2447
#16 0x00000000102e4a64 in stl_phys (addr=0x10080000048, val=0xe2ff0000)
    at /home/alexey/pcipassthru/qemu-impreza/exec.c:2469
#17 0x00000000103550d8 in h_logical_store (cpu=0x1fffff0f0010,
spapr=0x10fe9510, opcode=0x40,
    args=0x1ffffffd0030) at
/home/alexey/pcipassthru/qemu-impreza/hw/ppc/spapr_hcall.c:570
#18 0x0000000010355698 in spapr_hypercall (cpu=0x1fffff0f0010, opcode=0x40,
args=0x1ffffffd0030)
    at /home/alexey/pcipassthru/qemu-impreza/hw/ppc/spapr_hcall.c:689






On 07/19/2013 10:49 PM, Paolo Bonzini wrote:
> Il 19/07/2013 13:09, Alexey Kardashevskiy ha scritto:
>> Hi!
>>
>> This patch also breaks virtio on powerpc. I thought it was fixed
>> (reverted?) in the master branch from qemu.org but it is still there. What
>> did I miss?
> 
> It was not reverted, only the "DEVICE_LITTLE_ENDIAN" marking was.
> 
> Let me check if I can reproduce this, it looks like a endianness
> problems reading virtio-blk config space.
> 
> Paolo
> 
>> Trying to load:  from: disk ... virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> virtioblk_read: Access beyond end of device!
>> [many of those]
>>
>>
>>
>> On 07/11/2013 10:29 PM, Alexander Graf wrote:
>>>
>>> On 24.06.2013, at 08:07, Jan Kiszka wrote:
>>>
>>>> On 2013-06-23 22:50, Hervé Poussineau wrote:
>>>>> Jan Kiszka a écrit :
>>>>>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>>>>>
>>>>>> The current ioport dispatcher is a complex beast, mostly due to the
>>>>>> need to deal with old portio interface users. But we can overcome it
>>>>>> without converting all portio users by embedding the required base
>>>>>> address of a MemoryRegionPortio access into that data structure. That
>>>>>> removes the need to have the additional MemoryRegionIORange structure
>>>>>> in the loop on every access.
>>>>>>
>>>>>> To handle old portio memory ops, we simply install dispatching handlers
>>>>>> for portio memory regions when registering them with the memory core.
>>>>>> This removes the need for the old_portio field.
>>>>>>
>>>>>> We can drop the additional aliasing of ioport regions and also the
>>>>>> special address space listener. cpu_in and cpu_out now simply call
>>>>>> address_space_read/write. And we can concentrate portio handling in a
>>>>>> single source file.
>>>>>>
>>>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>>>> ---
>>>>>
>>>>> ...
>>>>>
>>>>>> +
>>>>>> +static void portio_write(void *opaque, hwaddr addr, uint64_t data,
>>>>>> +                         unsigned size)
>>>>>> +{
>>>>>> +    MemoryRegionPortioList *mrpio = opaque;
>>>>>> +    const MemoryRegionPortio *mrp = find_portio(mrpio, addr, size,
>>>>>> true);
>>>>>> +
>>>>>> +    if (mrp) {
>>>>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data);
>>>>>> +    } else if (size == 2) {
>>>>>> +        mrp = find_portio(mrpio, addr, 1, true);
>>>>>> +        assert(mrp);
>>>>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data & 0xff);
>>>>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr + 1, data
>>>>>>>> 8);
>>>>>> +    }
>>>>>> +}
>>>>>> +
>>>>>> +static const MemoryRegionOps portio_ops = {
>>>>>> +    .read = portio_read,
>>>>>> +    .write = portio_write,
>>>>>> +    .valid.unaligned = true,
>>>>>> +    .impl.unaligned = true,
>>>>>> +};
>>>>>> +
>>>>>
>>>>> You need to mark these operations as DEVICE_LITTLE_ENDIAN.
>>>>> In portio_write above, you clearly assume that data is in LE format.
>>>>
>>>> Anything behind PIO is little endian, of course. Will add this.
>>>
>>> This patch breaks VGA on PPC as it is in master today.
>>>
>>>
>>> Alex
>>>
>>>>
>>>>>
>>>>> This fixes PPC PReP emulation, which would otherwise be broken with this
>>>>> patchset.
>>>>
>>>> Thanks,
>>>> Jan
>>>>
>>>>
>>>
>>>
>>
>>
> 


-- 
Alexey