Re: [RFC/RFT PATCH 0/2] x86: sgx_vepc: implement ioctl to EREMOVE all pages

Jarkko Sakkinen
2021-09-14T17:40:52Z

On Tue, 2021-09-14 at 19:07 +0200, Paolo Bonzini wrote:
> On 14/09/21 18:42, Jarkko Sakkinen wrote:
> > > Let's wait for this patch to be accepted first. I'll wait a little more
> > > for Jarkko and Dave to comment on this, and include your "Tested-by".
> > >
> > > I will also add cond_resched() on the final submission.
> > Why these would be conflicting tasks? I.e. why could not QEMU use
> > what is available now and move forward using better mechanism, when
> > they are available?
>
> The implementation using close/open is quite ugly (destroying and
> recreating the memory block breaks a few levels of abstractions), so
> it's not really something I'd like to commit.

OK, so the driving reason for SGX_IOC_VEPC_RESET is the complex dance
with opening, closing and mmapping() stuff, especially when dealing
with multiple sections for one VM? OK, I think I can understand this,
given how notorious it might be to get stable in the user space.

Please just document this use case some way (if I got it right) to
the commit message of the next version, and I think this starts to
make much more sense.

/Jarkko