Re: [PATCH v4 11/16] Add live migration of VMware's hyper-call RPC

[Don Slutz <dslutz@verizon.com>]

On 09/12/14 09:54, Boris Ostrovsky wrote:
> On 09/11/2014 02:36 PM, Don Slutz wrote:
>> The VMware's hyper-call state is included in live migration and
>> save/restore.  Because the max size of the VMware guestinfo is
>> large, then data is compressed and expanded in the
>> vmport_save_domain_ctxt and vmport_load_domain_ctxt.
>>
>> Signed-off-by: Don Slutz <dslutz@verizon.com>
>> ---
>>


>> +
>> +    for ( i = 0; i < ctxt->used_guestinfo; i++ )
>> +    {
>> +        vmport_guestinfo_t *vg = vs->guestinfo[i];
>> +
>> +        if ( vg && vg->key_len )
>> +        {
>> +            guestinfo_size += sizeof(vg->key_len) + 
>> sizeof(vg->val_len) +
>> +                vg->key_len + vg->val_len;
>> +            used_guestinfo++;
>> +            ASSERT(sizeof(vg->key_len) == 1);
>> +            *p++ = (char) vg->key_len;
>> +            ASSERT(sizeof(vg->val_len) == 1);
>> +            *p++ = (char) vg->val_len;
>> +            if ( vg->key_len )
>
> You ASSERTed that vg->key_len is 1 so you may not need the 'if'. (And 
> in NDEBUG version the worst that could happen is you do memcpy(,,0), 
> which is safe).
>

You seem to have missed the sizeof() in there.   So vg->key_len can be 
zero.  But I will agree
that the if could be dropped.

>> +            {
>> +                memcpy(p, vg->key_data, vg->key_len);
>> +                p += vg->key_len;
>> +                if ( vg->val_len )
>
> Same here.
>

Yes, the if is not needed.  Can drop if requested.

>> +                {
>> +                    memcpy(p, vg->val_data, vg->val_len);
>> +                    p += vg->val_len;
>> +                }
>> +            }
>> +        }
>> +    }
>> +    ctxt->used_guestinfo = used_guestinfo;
>> +
>> +    for ( i = 0; i < ctxt->used_guestinfo_jumbo; i++ )
>> +    {
>> +        vmport_guestinfo_jumbo_t *vgj =
>> +            vs->guestinfo_jumbo[i];
>> +        if ( vgj && vgj->key_len )
>> +        {
>> +            guestinfo_size += sizeof(vgj->key_len) + 
>> sizeof(vgj->val_len) +
>> +                vgj->key_len + vgj->val_len;
>> +            used_guestinfo_jumbo++;
>> +            ASSERT(sizeof(vgj->key_len) == 1);
>> +            *p++ = (char) vgj->key_len;
>> +            memcpy(p, &vgj->val_len, sizeof(vgj->val_len));
>> +            p += sizeof(vgj->val_len);
>> +            if ( vgj->key_len )
>
> And here.
>
> And do you need ASSERT(vgj->val_len ==1) as well? Also, In 
> vmport_load_domain_ctxt() you don't seem to be making this assertions. 
> I don't know whether this is on purpose.
>

In this case sizeof(vgj->val_len) != 1.

I will add ASSERTs there also.




>> +
>> +    if ( !vs )
>> +        return -ENOMEM;
>> +
>> +    /* Customized checking for entry since our entry is of variable 
>> length */
>> +    desc = (struct hvm_save_descriptor *)&h->data[h->cur];
>> +    if ( sizeof(*desc) > h->size - h->cur )
>> +    {
>> +        printk(XENLOG_G_WARNING
>> +               "HVM%d restore: not enough data left to read descriptor"
>> +               "for type %lu\n", d->domain_id,
>> +               HVM_SAVE_CODE(VMPORT));
>> +        return -1;
>
> Since in some cases you are returning proper error codes you should 
> return them everywhere.
>

Will adjust to proper error codes.

    -Don Slutz

> -boris
>
>