Re: [patch 5/9] x86/ioport: Reduce ioperm impact for sane usage further
From: Linus Torvalds
Date: Thu Nov 07 2019 - 11:53:49 EST
On Thu, Nov 7, 2019 at 8:45 AM Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>
> Further a quick look shows that dosemu uses ioperm in a fine grained
> manner. From memory it would allow a handful of ports to allow directly
> accessing a device and depended on the rest of the port accesses to be
> disallowed so it could trap and emulate them.
Yes. Making ioperm() some all-or-nothing thing would be horribly bad,
and has no real advantages that I can see.
Linus