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

[Artyom Tarasenko <atar4qemu@googlemail.com>]

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?

> 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.