On Thu, Jun 03, 2010 at 02:41:38PM -0700, Tom Lyon wrote: > OK, in the interest of making progress, I am about to embark on the following: > > 1. Create a user-iommu-domain driver - opening it will give a new empty > domain. > Ultimately this can also populate sysfs with the state of its world, > which would > also be a good addition to the base iommu stuff. > If someone closes the fd while in use, the domain stays valid anyway > until users > drop off. > > 2. Add DOMAIN_SET and DOMAIN_UNSET ioctls to the vfio driver. Require that > a domain be set before using the VFIO_DMA_MAP_IOVA ioctl
Require domain to be set before you allow any access to the device: mmap, write, read. IMO this is the only safe way to make sure userspace does not corrupt memory, and this removes the need to special-case MSI memory, play with bus master enable and hope it can be cleared without reset, etc. > (this is the one > that KVM wants). Not sure I understand. I think that MAP should be done on the domain, not the device, this handles pinning pages correctly and this way you don't need any special checks. > However, the VFIO_DMA_MAP_ANYWHERE ioctl is the one > which uses the dma_sg interface which has no expicit control of domains. I > intend to keep it the way it is, but expect only non-hypervisor programs > would > want to use it. If we support MAP_IOVA, why is MAP_ANYWHERE useful? Can't non-hypervisors just pick an address? > 3. Clean up the docs and other nits that folks have found. > > Comments? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
