Re: [RFC PATCH v3 00/27] KVM SGX virtualization support

Sean Christopherson
2021-02-03T23:33:49Z

On Thu, Feb 04, 2021, Kai Huang wrote:
> On Wed, 2021-02-03 at 09:46 -0800, Dave Hansen wrote:
> > On 2/3/21 9:43 AM, Paolo Bonzini wrote:
> > > On 03/02/21 18:36, Sean Christopherson wrote:
> > > > I'm not at all opposed to preventing KVM from accessing EPC, but I
> > > > really don't want to add a special check in KVM to avoid reading EPC.
> > > > KVM generally isn't aware of physical backings, and the relevant KVM
> > > > code is shared between all architectures.
> > >
> > > Yeah, special casing KVM is almost always the wrong thing to do.
> > > Anything that KVM can do, other subsystems will do as well.
> >
> > Agreed. Thwarting ioremap itself seems like the right way to go.
>
> This sounds irrelevant to KVM SGX, thus I won't include it to KVM SGX series.

I would say it's relevant, but a pre-existing bug. Same net effect on what's
needed for this series..

I say it's a pre-existing bug, because I'm pretty sure KVM can be coerced into
accessing the EPC by handing KVM a memslot that's backed by an enclave that was
created by host userspace (via /dev/sgx_enclave).