Re: Design doc of adding ACPI support for arm64 on Xen - version 2

[Shannon Zhao <shannon.zhao@linaro.org>]

On 2015/8/12 17:11, Julien Grall wrote:
> On 12/08/2015 08:22, Shannon Zhao wrote:
>> Hi,
>
> Hi Shannon,
>
> It's not part of the design discussion and we are avoiding to mix
> discussion. Can you please create another thread (or at least renaming
> the subject)?
>
>> I'm working on re-spinning this patchset while encountering a werid
>> problem about xzalloc_bytes.
>>
>> Since I need to copy some ACPI tables, I need to allocate some memory
>> for it. So there are a few places calling xzalloc_bytes. And it fails at
>> the fifth one. The log is shown as following:
>
> Do you copy data in the newly allocated memory between 2 xzalloc_bytes?
>

No, I just use xzalloc_bytes to allocate some place and copy ACPI to the 
allocated place, modify the content, then call 
raw_copy_to_guest_flush_dcache to copy the modified tables to guest memory.

> The only thing I have in mind based on the log below is your are
> overriding the metadata of the memory allocator.
>
>> (XEN) *** LOADING DOMAIN 0 ***
>> (XEN) Loading kernel from boot module @ 00000008fa315000
>> (XEN) Allocating 1:1 mappings totalling 256MB for dom0:
>> (XEN) BANK[0] 0x00000090000000-0x000000a0000000 (256MB)
>> (XEN) Grant table range: 0x00000087e00000-0x00000087e5b000
>> (XEN) Loading zImage from 00000008fa315000 to
>> 0000000090080000-00000000909e0ec8
>> (XEN) Hypervisor Trap. HSR=0x96000044 EC=0x25 IL=1 Syndrome=0x44
>> (XEN) CPU0: Unexpected Trap: Hypervisor
>> (XEN) ----[ Xen-4.6-unstable  arm64  debug=y  Not tainted ]----
>> (XEN) CPU:    0
>> (XEN) PC:     0000000000238b78 xmem_pool_alloc+0x348/0x4b0
>> (XEN) LR:     0000000000238960
>> (XEN) SP:     00000000002bf4e0
>> (XEN) CPSR:   20000249 MODE:64-bit EL2h (Hypervisor, handler)
>>
>> (XEN) Xen call trace:
>> (XEN)    [<0000000000238b78>] xmem_pool_alloc+0x348/0x4b0 (PC)
>> (XEN)    [<0000000000238960>] xmem_pool_alloc+0x130/0x4b0 (LR)
>> (XEN)    [<0000000000239100>] _xmalloc+0xf4/0x290
>> (XEN)    [<00000000002392b0>] _xzalloc+0x14/0x38
>> (XEN)    [<0000000000245430>] construct_dom0+0xbc0/0x14cc
>> (XEN)    [<000000000028c4c4>] start_xen+0xbf4/0xcb0
>> (XEN)    [<000000000020060c>] paging+0x84/0xbc
>> (XEN)
>> (XEN)
>> (XEN) ****************************************
>> (XEN) Panic on CPU 0:
>> (XEN) CPU0: Unexpected Trap: Hypervisor
>> (XEN)
>> (XEN) ****************************************
>> (XEN)
>> (XEN) Reboot in five seconds...
>>
>
> Regards,
>

-- 
Shannon