On Tue, 2021-01-26 at 07:49 -0800, Dave Hansen wrote: > On 1/26/21 1:30 AM, Kai Huang wrote: > > From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > > > SGX virtualization requires to allocate "raw" EPC and use it as "virtual > > EPC" for SGX guest. Unlike EPC used by SGX driver, virtual EPC doesn't > > track how EPC pages are used in VM, e.g. (de)construction of enclaves, > > so it cannot guarantee EREMOVE success, e.g. it doesn't have a priori > > knowledge of which pages are SECS with non-zero child counts. > > The grammar there is a bit questionable in spots. Here's a rewrite: > > SGX can accurately track how bare-metal enclave pages are used. This > enables SECS to be specifically targeted and EREMOVE'd only after all > child pages have been EREMOVE'd. This ensures that bare-metal SGX will > never encounter SGX_CHILD_PRESENT in normal operation. How about: "SGX driver can accurate track how enclave pages are used. This enables..." Since in another email, you mentioned that we should get rid of bare-metal driver, and Andy suggested we can just use SGX driver? > > Virtual EPC is different. The host does not track how EPC pages are > used by the guest, so it cannot guarantee EREMOVE success. It might, > for instance, encounter a SECS with a non-zero child count. > > Aside: Would it be *possible* for the host to figure out where the SECS > pages are? If not, we can say "host can not track" versus what I said: > "host does not track". Technically it is possible, so "host does not track" is more reasonable. > > > Add SGX_CHILD_PRESENT for use by SGX virtualization to assert EREMOVE > > failures are expected, but only due to SGX_CHILD_PRESENT. > > > > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > Acked-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> > > Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx> > > With the improved changelog: > > Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx> Thanks.
