Hi Damien,
Thanks a lot for your inputs.
On 06/12/2021 00:12, Damien Le Moal wrote:
On 2021/12/03 20:11, Ayan Kumar Halder wrote:
Hi All,
I am trying to run linux as a DomU guest on Xen with AHCI assigned to it.
I can confirm that SATA works (ie able to detect sdb) as a Dom0 guest.
However, it does not work as a DomU guest.
Hardware :- ZCU102 board and it has two sata ports
Kernel :- 5.10
I have enabled the debug logs in drivers/ata
1. Logs from dom0 (where SATA works) https://pastebin.com/2BhMDq47
2. Logs from domU (where SATA does not work) https://pastebin.com/fE8WZnZ0
Can some help me to answer these questions
1. What does this mean "1st FIS failed" ?
2. In the dom0 logs, PORT_SCR_ERR = 0x41d0002 whereas in domU logs,
PORT_SCR_ERR = 0. Does it give some hints ?
3. Any other issues or hints to debug this ?
I can confirm that in domU scenario, we do not get any interrupts from
the device. What might be going wrong here ?
That would be the first thing to check since without interrupts you will not get
any command completion. Commands will timeout and probe will not work.
And this IRQ problem is Xen territory, not ata.
I am actually debugging the interrupts from the Xen's side. I can
confirm that do_IRQ() (Xen's irq handler) does not receive AHCI
interrupts. It does get invoked for interrupts from serial and other
devices.
I have seen commands being timed out which is due to the iRQ issue. But
suprisingly, ahci probe is successful.
The 1st FIS failed error may be due to some problems with AHCI PCI bar/register
accesses, which may not be working. This I think points again to Xen setup with
domU, which may not have the necessary access rights to get IRQ and PCI bar
accesses ? (I have no experience with Xen)
This is the device tree https://pastebin.com/HtdLx63v . I think it is
not related to PCI bus. Please correct me if mistaken.
I have the necessary debug support from Xen. Can you let me know what
bits I can debug from SATA side (for eg reading a particular register)
which will confirm if SATA has been programmed correctly or not ?
- Ayan
Thanks in advance.
Kind regards,
Ayan
