Re: [Qemu-devel] [PATCH] linux-user: do setrlimit selectively

[Peter Maydell]

On 4 September 2018 at 23:02, Max Filippov <address@hidden> wrote:
> On Tue, Sep 4, 2018 at 2:13 PM, Peter Maydell <address@hidden> wrote:
>> I think the issue here is not related to 32-on-64 but to the fact
>> that we just pass through the memory rlimits. What we should ideally
>> be doing is tracking the actual guest memory allocations sufficiently
>> that we can then apply the rlimits at the QEMU level, so that guest
>> allocations that breach limits can be failed, without ever causing
>> QEMU's own alloactions to fail.
>
> In a sense we do it by limiting 32-bit guest to 32 or less bits of the address
> space, that's why it should be rather safe to just ignore setrlimit calls in
> 32-on-64 case.

I'm not sure why you think that we should treat 32-on-64 differently.
You could make a case for always ignoring setrlimit calls: if we
ever hit the limit it's as likely to be by failing a QEMU internal
allocation as a guest one, so not to imposing the limit at all
would avoid QEMU failing then. But that would apply in both the
32-on-64 and also 32-on-32 and 64-on-64 cases too.

thanks
-- PMM