Re: [PATCH v2] ata: ahci: Add mask_port_map module parameter

[Damien Le Moal <dlemoal@kernel.org>]

On 4/6/24 07:53, Conrad Kostecki wrote:
> Hi Damien,
> 
> Am 05.04.2024 14:51:43, "Damien Le Moal" <dlemoal@kernel.org> schrieb:
> 
>> <PATCH v2>
> i did run a test on my hardware.
> It seems to work and adjusting the port_map. But I noticed a difference, that
> those virtual hostXY ports are not marked as DUMMY.
> With the previous patch, only six ports reported "ahci" and rest "DUMMY".
> I am not sure, if that should also not happen with your patch?
> Conrad
> [   13.365573] ahci 0000:09:00.0: masking port_map 0xffffff3f -> 0x3f
> [   13.376511] ahci 0000:09:00.0: SSS flag set, parallel bus scan disabled
> [   13.395670] ahci 0000:09:00.0: AHCI 0001.0301 32 slots 32 ports 6 Gbps 0x3f
> impl SATA mode
> [   13.397111] ahci 0000:09:00.0: flags: 64bit ncq sntf stag pm led only pio
> sxs deso sadm sds apst
> [   13.593757] scsi host9: ahci
> [   13.597362] scsi host10: ahci
> [   13.600949] scsi host11: ahci
> [   13.604548] scsi host12: ahci
> [   13.612459] scsi host13: ahci
> [   13.616027] scsi host14: ahci
> [   13.616437] scsi host15: ahci
> [   13.616745] scsi host16: ahci
> [   13.617039] scsi host17: ahci
> [   13.617415] scsi host18: ahci
> [   13.617723] scsi host19: ahci
> [   13.637158] scsi host20: ahci
> [   13.640666] scsi host21: ahci
> [   13.651760] scsi host22: ahci
> [   13.652311] scsi host23: ahci
> [   13.652850] scsi host24: ahci
> [   13.656374] scsi host25: ahci
> [   13.664120] scsi host26: ahci
> [   13.664570] scsi host27: ahci
> [   13.686567] scsi host28: ahci
> [   13.690179] scsi host29: ahci
> [   13.697603] scsi host30: ahci
> [   13.698083] scsi host31: ahci
> [   13.698518] scsi host32: ahci
> [   13.701855] scsi host33: ahci
> [   13.702323] scsi host34: ahci
> [   13.702745] scsi host35: ahci
> [   13.721520] scsi host36: ahci
> [   13.725157] scsi host37: ahci
> [   13.736948] scsi host38: ahci
> [   13.737383] scsi host39: ahci
> [   13.748518] scsi host40: ahci

These messages are normal. ata port stucture which leads to a scsi host are
still created for dummy ports. So seeing all ports here as scsi hosts is
normal. However, after these messages, you should see a "ataX: DUMMY" message.

Example with a qemu VM with a 6-ports AHCI controller:

Using the ahci driver without any port map mask, I get:

[  318.739513] ahci 0000:00:1f.2: AHCI vers 0001.0000, 32 command slots, 1.5
Gbps, SATA mode
[  318.741283] ahci 0000:00:1f.2: 6/6 ports implemented (port mask 0x3f)
[  318.742619] ahci 0000:00:1f.2: flags: 64bit ncq only
[  318.759156] scsi host0: ahci
[  318.764098] scsi host1: ahci
[  318.788722] scsi host2: ahci
[  318.793502] scsi host3: ahci
[  318.797792] scsi host4: ahci
[  318.801843] scsi host5: ahci
[  318.804550] ata13: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16100
irq 40 lpm-pol 3
[  318.805753] ata14: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16180
irq 40 lpm-pol 3
[  318.807045] ata15: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16200
irq 40 lpm-pol 3
[  318.808322] ata16: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16280
irq 40 lpm-pol 3
[  318.809595] ata17: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16300
irq 40 lpm-pol 3
[  318.810829] ata18: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16380
irq 40 lpm-pol 3
...

On the same VM, if I rmmod ahci and modprobe it with mask_port_map=0x1
(enabling only the first port), I get:

[  362.257874] ahci 0000:00:1f.2: masking port_map 0x3f -> 0x1
[  362.260518] ahci 0000:00:1f.2: AHCI vers 0001.0000, 32 command slots, 1.5
Gbps, SATA mode
[  362.262477] ahci 0000:00:1f.2: 1/6 ports implemented (port mask 0x1)
[  362.263917] ahci 0000:00:1f.2: flags: 64bit ncq only
[  362.281765] scsi host0: ahci
[  362.286353] scsi host1: ahci
[  362.290785] scsi host2: ahci
[  362.301082] scsi host3: ahci
[  362.324192] scsi host4: ahci
[  362.329560] scsi host5: ahci
[  362.332692] ata19: SATA max UDMA/133 abar m4096@0xfea16000 port 0xfea16100
irq 40 lpm-pol 3
[  362.335041] ata20: DUMMY
[  362.335872] ata21: DUMMY
[  362.336828] ata22: DUMMY
[  362.337856] ata23: DUMMY
[  362.338660] ata24: DUMMY

So the last 5 ports are now dummies...

Can you confirm that you see this please ? Also, please confirm that boot time
is OK and faster with the port map mask.



-- 
Damien Le Moal
Western Digital Research