[Qemu-devel] Re: sparc esp NetBSD-guest "sd3: mode sense (4) returned nonsense"

[Blue Swirl <blauwirbel@gmail.com>]

On Mon, Sep 14, 2009 at 7:29 PM, Artyom Tarasenko
<atar4qemu@googlemail.com> wrote:
> 2009/9/14 Blue Swirl <blauwirbel@gmail.com>:
>> On Mon, Sep 14, 2009 at 12:32 AM, Artyom Tarasenko
>> <atar4qemu@googlemail.com> wrote:
>>> From NetBSD source, it looks like HDD geometry detection should work
>>> under qemu: they call "mode sense" and "read capacity", and both
>>> commands are implemented in qemu's hw/scsi-disk.h. It doesn't work
>>> though, so NetBSD has to fabricate a disk geometry.
>>>
>>> To make debugging easier I tried to boot an older version - NetBSD
>>> 1.3.3. And put some extra debugging in esp.c:
>>>
>>> static uint32_t get_cmd(ESPState *s, uint8_t *buf)
>>> {
>>>    uint32_t dmalen;
>>>    int target;
>>>
>>>    target = s->wregs[ESP_WBUSID] & BUSID_DID;
>>>    if (s->dma) {
>>>        dmalen = s->rregs[ESP_TCLO] | (s->rregs[ESP_TCMID] << 8);
>>>        s->dma_memory_read(s->dma_opaque, buf, dmalen);
>>>    } else {
>>>        dmalen = s->ti_size;
>>>        memcpy(buf, s->ti_buf, dmalen);
>>> printf("NON-DMA rptr %d, wptr %d %2x (0) %2x %2x %2x %2x\n",
>>> s->ti_rptr, s-> ti_wptr, buf[0],buf[1], buf[2],buf[3], buf[4]);
>>>        buf[0] = 0;
>>>    }
>>>
>>> qemu-system-sparc -M SS-20 -nographic  -hda ~/sparc/miniroot-133.fs -m 64
>>> ...
>>> NON-DMA rptr 0, wptr 1 c0 (0)  0  0 1a  0
>>> Set ATN & Stop: cmdlen 3
>>> scsi-disk: Command: lun=0 tag=0x0 data=0x00 0x00 0x1a 0x00 0x04 0x00
>>> scsi-disk: Test Unit Ready
>>> scsi-disk: Command complete tag=0x0 status=0 sense=0
>>> sd3: mode sense (4) returned nonsense; using fictitious geometry
>>>
>>>
>>> NetBSD sent command "0x1a" via Set ATN & Stop, but it for some reason
>>> the command got padded and disk got "0x0 0x0 0x1a", no wonder that its
>>> output looks like a non-sense to NetBSD.
>>>
>>> Any ideas why does it happen?
>>>
>>
>> The problem could be in the DMA (sparc32_dma.c), or incorrect
>> programming of DMA or IOMMU DVMA by NetBSD, (or bug in iommu.c).
>
> Why DMA? It hits the else branch of "if (s->dma)". Does the command
> still get in via DMA?

Sorry, I missed that. But is the response also read without DMA?

>> All
>> my NetBSD <4.0 boot CDs crash because of a NMI from IOMMU (DMA tries
>> to access a page not in IOMMU tables). The changes in NetBSD
>> Sparc/ESP/DMA/IOMMU code from 3.x to 4.0 could be enlightening.
>
> Only indirect, because capacity reading doesn't work with NetBSD 4 as well.
>
> BTW is esp also used in non-sparc systems? AFAIR NCR53C9x chip was
> also used on some apple machines?
> One possibility to exclude esp from suspects would be to boot the same
> version of NetBSD on other qemu-guest arch.

At least MIPS Jazz machines use it.