I understood what was said by the way about the permissions. I temporarily switched off SElinux. I think I just may not be entering the command correctly. If I put home/testa/image.dump I get Could not open 'image.dump' If I put /home/testa/image.dump I get Invalid char in expression from the first slash. Can someone who has gotten this to work please tell me how they typed out the entire command in full detail? I don't really care where it saves it, I just need the dump of the memory. I have tried this with various forms of the path: sudo virsh qemu-monitor-command --hmp Shawn 'pmemsave 0 536870912 image.dump' Regards, Shawn -----Original Message----- From: Eric Blake [mailto:eblake@xxxxxxxxxx] Sent: Tuesday, March 20, 2012 10:09 AM To: Shawn Davis Cc: libvirt-users@xxxxxxxxxx Subject: Re: qemu-monitor-command On 03/20/2012 07:30 AM, Shawn Davis wrote: > Hello Everyone, > > I am working on a grad school project for virtual introspection. I > have a vm running (with 512mb of memory) and want to access the > pmemsave function through virsh with the qemu-monitor-command. Why? I would just access it through the public API virDomainMemoryPeek instead, then you don't have to worry about the nuances. Alas, virDomainMemoryPeek has not yet been wired into virsh (patches welcome!), so you'll have to access it through a custom C program, or through one of the other language bindings such as python or perl. > virsh qemu-monitor-command --hmp Shawn 'pmemsave 0 536870912 image.dump' > > Shawn is the name of my vm and image.dump is the name of my output > file. No matter what I do, I keep getting: Could not open 'image.dump' That's because when you do raw pass-through like this, you are asking qemu to open the relative pathname 'image.dump', relative to the current working directory of qemu, which isn't necessarily the current working directory of your virsh process. Furthermore, if you are accessing a remote connection (such as -c qemu+ssh://remote/system), the file name is relative to the remote system, but you probably want the file to appear on the machine where you are running virsh. Finally, if SELinux is in effect, you have to ensure that qemu has proper permissions, including SELinux label, to open() the file; this is something that libvirt can do for you via the virDomainMemoryPeek API, but if you go through qemu-monitor-command, you are on your own. -- Eric Blake eblake@xxxxxxxxxx +1-919-301-3266 Libvirt virtualization library http://libvirt.org
