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

[Wei Xu <xuwei5@xxxxxxxxxxxxx>]

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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