On Wed, Mar 31, 2010 at 02:25:35PM -0700, Chris Wright wrote: > * Neil Horman (nhorman at tuxdriver.com) wrote: > > Flush iommu during shutdown > > > > When using an iommu, its possible, if a kdump kernel boot follows a primary > > kernel crash, that dma operations might still be in flight from the previous > > kernel during the kdump kernel boot. This can lead to memory corruption, > > crashes, and other erroneous behavior, specifically I've seen it manifest during > > a kdump boot as endless iommu error log entries of the form: > > AMD-Vi: Event logged [IO_PAGE_FAULT device=00:14.1 domain=0x000d > > address=0x000000000245a0c0 flags=0x0070] > > We've already fixed this problem once before, so some code shift must > have brought it back. Personally, I prefer to do this on the bringup > path than the teardown path. Besides keeping the teardown path as > simple as possible (goal is to get to kdump kernel asap), there's also > reason to competely flush on startup in genernal in case BIOS has done > anything unsavory. Can we flush domains (all the I/O TLBs assciated with each domain), during initialization? I think all the domain data built by previous kernel will be lost and new kernel will have no idea about. Thanks Vivek
