Re: [RFC][PATCH] Cross Memory Attach

[Avi Kivity <avi@redhat.com>]

  On 09/15/2010 04:46 PM, Bryan Donlan wrote:
> On Wed, Sep 15, 2010 at 19:58, Avi Kivity<avi@redhat.com>  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).

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.