On 09/15/2010 04:46 PM, Bryan Donlan wrote:
On Wed, Sep 15, 2010 at 19:58, Avi Kivity<avi@xxxxxxxxxx> wrote:
Instead of those two syscalls, how about a vmfd(pid_t pid, ulong start,
ulong len) system call which returns an file descriptor that represents a
portion of the process address space. You can then use preadv() and
pwritev() to copy memory, and io_submit(IO_CMD_PREADV) and
io_submit(IO_CMD_PWRITEV) for asynchronous variants (especially useful with
a dma engine, since that adds latency).
With some care (and use of mmu_notifiers) you can even mmap() your vmfd and
access remote process memory directly.
Rather than introducing a new vmfd() API for this, why not just add
implementations for these more efficient operations to the existing
/proc/$pid/mem interface?
Yes, opening that file should be equivalent (and you could certainly
implement aio via dma for it).
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