On Fri, Jun 22, 2007 at 03:32:53PM -0600, Eric W. Biederman wrote: > Alan Cox <[EMAIL PROTECTED]> writes: > > > You've got mapped live gart pages from the previous kernel. Even > > if you disable the gart before a memset you may well have the > > video card using gart translations and possibly live IOMMU > > mappings for devices using it via bus mastering - and those will > > cause you MCE exceptions with a corrupt cpu context flag (ie not > > nicely recoverable). > > The original plan (which we have not followed up on). Was to > reserve a chunk of any iommu for the kexec on panic kernel. Then to > just have the second kernel use that unused chunk. This is how we > treat the normal memory space and it seems a nice and simple > approach to this kind of problem. > > For a normal kexec we should shut everything down before the kernel > transition so it should not be an issue. > > YH do you think you can look at simply reserving a portion of the > iommu? And having the kexec on panic kernel use the reserved > portion?
How would this work with an isolation capable IOMMU which has different address spaces for different devices? (e.g., Calgary which is in mainline, Intel's VT-d which is coming soon, etc). Cheers, Muli - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
