On 4/17/11 5:43 AM, "Avi Kivity" <a...@redhat.com> wrote: >On 04/16/2011 02:58 AM, Ritchie, Stuart wrote: >> > >> >You can do this with ivshmem today. You give it a path to a shared >> >memory file, and then there's a path in sysfs that you can mmap() in >> >userspace in the guest. >> >> Please correct me if I am wrong, but with ivshmem you must to manage >>your >> world within a single, fixed size region. I appreciate the simplicity >>of >> mapping the whole region all in one go, but our requirements are a bit >> different. Even if you could pass multiple -device ivshmem instances, >> it's still a fixed environment. Right? >> > >You could place a read-only filesystem (say iso9660) in the region and >mount it; it will then appear as a complete filesystem.
We've thought about formatting the region as a ramdisk, but the block layer shields mmap() from the storage, thus requiring a data copy into the page-cache. The great thing about ramfs/tmpfs is the data is used in-place; we'd lose that when going with a ramdisk or other real filesystem. --Stuart ============================================================ The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any reproduction, dissemination or distribution of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. Thank you. Tellabs ============================================================
