Re: [Xen-devel] [PATCH] xen/arm: vgic-v3: Fix the typo of GICD IRQ active status range

[Wei Xu <xuwei5@hisilicon.com>]

Hi Julien,

On 2020/1/7 23:12, Julien Grall wrote:
>
>
> On 07/01/2020 12:55, Wei Xu wrote:
>> Hi Julien,
>>> As only one entity should manage the UART (i.e Xen or Dom0), we 
>>> today assume this will be managed by Xen. Xen should expose a 
>>> partial virtual UART (only a few registers are emulating) to dom0 in 
>>> replacement.
>>>
>>> This is usually done by the UART driver. Looking at the log you 
>>> pasted in a separate e-mail:
>>>
>>> (XEN) Platform: Generic System
>>> (XEN) Unable to initialize acpi uart: -9
>>> (XEN) Bad console= option 'dtuart'
>>>
>>> So Xen didn't manage to initialize the uart. The -9 suggests, Xen 
>>> didn't find a driver for your UART. At the moment, Xen is only able 
>>> to detect pl011, sbsa, sbsa32 UART for ACPI. What is the type of the 
>>> UART used on your platform?
>>>
>>
>> Thanks!
>> Got it.
>> Our UART is 8250.
>
> You would need to teach the 8250 driver how to initialize the UART 
> with ACPI. It is not very difficult to do it, have a look at the pl011 
> version.
>
>>
>> Thanks!
>> It is not working even I changed the condition to " if ( 
>> acpi_disabled ) ".
>
> Doh, thank you for spotting the extra !.
>
>> My grub 2.04 configuration is as below:
>>
>>      xen_hypervisor /xen dom0_mem=4G acpi=force loglvl=all 
>> guest_loglvl=all
>>      xen_module /Image rdinit=/init  acpi=force noinitrd 
>> root=/dev/sdb1 rw
>>
>> The log with the condition " if ( acpi_disabled ) " is as following:
>>
>>      (XEN) Adding cpu 126 to runqueue 0
>>      (XEN) Adding cpu 127 to runqueue 0
>>      (XEN) alternatives: Patching with alt table 00000000002d4f48 -> 
>> 00000000002d5764
>>      (XEN) *** LOADING DOMAIN 0 ***
>>      (XEN) Loading d0 kernel from boot module @ 0000000016257000
>>      (XEN) Allocating 1:1 mappings totalling 4096MB for dom0:
>>      (XEN) BANK[0] 0x00000008000000-0x00000010000000 (128MB)
>>      (XEN) BANK[1] 0x00000020000000-0x00000038000000 (384MB)
>>      (XEN) BANK[2] 0x00000050000000-0x00000080000000 (768MB)
>>      (XEN) BANK[3] 0x00202000000000-0x00202080000000 (2048MB)
>>      (XEN) BANK[4] 0x002020b0000000-0x002020c0000000 (256MB)
>>      (XEN) BANK[5] 0x00202600000000-0x00202620000000 (512MB)
>>      (XEN) Grant table range: 0x000000181c7000-0x00000018207000
>>      (XEN) Allocating PPI 16 for event channel interrupt
>>      (XEN) Loading zImage from 0000000016257000 to 
>> 0000000008080000-0000000009981200
>>      (XEN) Loading d0 DTB to 0x000000000fe00000-0x000000000fe0025b
>>      (XEN) Initial low memory virq threshold set at 0x4000 pages.
>>      (XEN) Scrubbing Free RAM in background
>>      (XEN) Std. Loglevel: All
>>      (XEN) Guest Loglevel: All
>>      (XEN) *** Serial input to DOM0 (type 'CTRL-a' three times to 
>> switch input)
>>      (XEN) Data Abort Trap. Syndrome=0x6
>>      (XEN) Walking Hypervisor VA 0x10 on CPU0 via TTBR 
>> 0x00000000182ff000
>>      (XEN) 0TH[0x0] = 0x0000000018302f7f
>>      (XEN) 1ST[0x0] = 0x0000000018300f7f
>>      (XEN) 2ND[0x0] = 0x0000000000000000
>>      (XEN) CPU0: Unexpected Trap: Data Abort
>>      (XEN) ----[ Xen-4.13.0-rc  arm64  debug=y   Not tainted ]----
>>      (XEN) CPU:    0
>>      (XEN) PC:     00000000002b65c8 00000000002b65c8
>
> Can you look with addr2line what this PC refers to?
>

Sorry for the late reply!
The PC refers to fdt_num_mem_rsv during init_done.
But the device_tree_flattened is NULL that the data abort happened.

So I added below changes and the XEN dom0 can be booted.

     diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
     index 1e83351..1ab80a1 100644
     --- a/xen/arch/arm/setup.c
     +++ b/xen/arch/arm/setup.c
     @@ -392,7 +392,8 @@ void __init discard_initial_modules(void)
                   !mfn_valid(maddr_to_mfn(e)) )
                  continue;

     -        dt_unreserved_regions(s, e, init_domheap_pages, 0);
     +       if( acpi_disabled )
     +           dt_unreserved_regions(s, e, init_domheap_pages, 0);
          }

Thank you so much!

Best Regards,
Wei

> Cheers,
>



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