Bug 219850

Description of problem:

Using "xm mem-set Domain-0 2000000000" will pretend it did set
the value , ignoring the fact there is not even remotely this amount
of memory in the system.

Version-Release number of selected component (if applicable):

RHEL5 / B2 rev 2747 and 2836 

How reproducible:

Always

Steps to Reproduce:
1. "xm list" to display current value of "Mem" for Domain-0
2. "xm mem-set Domain-0 2000000000" to set a (bogus) large value
3. "xm list" will now claim Domain-0 has been ballooned up 2000000000
  
Actual results:

"xm list" will display bogus value for Domain-0

Expected results:

Xen should prevent the user from setting a bogus value for Domain-0
It should return an error if a value is selected which is larger than
the available memory

Additional info:

Sample session

[root@woodie ~]# xm list
Name                                      ID Mem(MiB) VCPUs State   Time(s)
Domain-0                                   0     2048     8 r-----  17125.8
rhel4pv-x86_64                            13     2048     1 -b----     89.9
rhel4u4esfv-x86_64                         2     2048     2 -b----   6838.6
rhel5b2vm01                                3     2048     2 -b----    820.2
rhel5b2vm02                               12     2048     1 -b----    167.5
[root@woodie ~]# xm mem-set 0 2000000000
[root@woodie ~]# xm list
Name                                      ID Mem(MiB) VCPUs State   Time(s)
Domain-0                                   0 2000000000     8 r-----  17132.1
rhel4pv-x86_64                            13     2048     1 -b----     89.9
rhel4u4esfv-x86_64                         2     2048     2 -b----   6839.0
rhel5b2vm01                                3     2048     2 -b----    820.2
rhel5b2vm02                               12     2048     1 -b----    167.5

Entries in /var/log/xen/xend.log

[2006-12-15 09:55:21 xend.XendDomainInfo 4110] DEBUG (XendDomainInfo:1014)
Setting memory target of domain Domain-0 (0) to 2048 MiB.
[2006-12-15 09:55:28 xend.XendDomainInfo 4110] DEBUG (XendDomainInfo:1014)
Setting memory target of domain Domain-0 (0) to 2000000000 MiB.

Entries from "xm dmesg"

(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (322 of 512)
(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (126 of 375)
(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (271 of 512)
(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (196 of 512)
(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (44 of 256)
(XEN) (file=memory.c, line=119) Could not allocate order=0 extent: id=0
memflags=0 (120 of 512)
8<---- snip 8<-----