Re: [RFC v3 1/6] xen/arm: Add basic save/restore support for ARM

[Wei Huang <w1.huang@samsung.com>]

On 05/14/2014 05:37 AM, Ian Campbell wrote:
> On Thu, 2014-05-08 at 16:18 -0500, Wei Huang wrote:
>> This patch implements a basic framework for ARM guest
>> save/restore. It defines a HVM save header for ARM guests
>> and correponding arch_ save/load functions. These functions
>
> "corresponding"
>
>> are hooked up with domain control hypercalls (gethvmcontext
>> and sethvmcontext). The hypercalls become a common code path to
>> both x86 and ARM. As a result of merging, the x86 specific
>> header saving code is moved to x86 sub-directory.
>>
>> Signed-off-by: Evgeny Fedotov <e.fedotov@samsung.com>
>> Signed-off-by: Wei Huang <w1.huang@samsung.com>
>
> Other than the comments already made by others this is looking good to
> me.
>
>> [...]
>> +#define HVM_ARM_FILE_MAGIC   0x92385520
>
> OOI where did that number come from? (often these are a few ASCII
> characters etc, I'm just curious)
No idea. I inherited from old patch. It doesn't seem to be meaningful 
ASCII string to me.
>
>> +#define HVM_ARM_FILE_VERSION 0x00000001
>> +
>> +/* Note: For compilation purpose hvm_save_header name is the same as x86,
>> + * but layout is different. */
>> +struct hvm_save_header
>> +{
>> +    uint32_t magic;             /* Must be HVM_ARM_FILE_MAGIC */
>> +    uint32_t version;           /* File format version */
>> +    uint32_t cpuinfo;           /* Record MIDR_EL1 info of saving machine */
>
> Is the size of this struct the same for arm32 and arm64?
The size is the same on arm32 and arm64.
>
> Ian.
>
>