On Wed, Apr 08, 2015 at 04:45:24PM +0100, Andrew Cooper wrote:
On 08/04/15 15:47, Konrad Rzeszutek Wilk wrote:
Hey Jim, Andrew, and Ian,
This is libvirt v1.2.14 + three patches: c82a59b libxl: drop virDomainObj lock when destroying a domain a1c9d30 libxl: acquire a job when destroying a domain 5bd5406 libxl: Move job acquisition in libxlDomainStart to callers
For fun I've set up an guest with PCI passthrough and tried to save it (HAHAH) with an disastrous result (xc_save_helper was stuck). Probably due to outstanding DMA operations wreaking havoc.
Outstanding DMA wont make any difference. It isn't (and can't) be reflected in the logdirty bitmap, so libxc simply wont know about it.
xc_save_helper is blocked because it has called back into the libxl with the suspend_and_state() callback.
i.e. libxc has requested that libxl pause the domain, and that request is still outstanding.
The vcpu trace from the very bottom shows that the guest has not yet paused itself. 1 vcpu is blocked in the hypervisor while the other look to be in some spinlock code.
Except the guest is in '---ss- ' so it _should_ be paused by now.
~Andrew