On 5/16/2017 12:46 AM, Jarkko Sakkinen wrote:
On Thu, May 11, 2017 at 08:28:37PM -0700, Andy Lutomirski wrote:
[resending due to some kind of kernel.org glitch -- sorry if anyone
gets duplicates]
On Thu, May 11, 2017 at 5:32 PM, Huang, Kai <kai.huang@xxxxxxxxxxxxxxx> wrote:
My current patch is based on this assumption. For KVM guest, naturally, we
will write the cached value to real MSRs when vcpu is scheduled in. For
host, SGX driver should write its own value to MSRs when it performs EINIT
for LE.
This seems unnecessarily slow (perhaps *extremely* slow) to me. I
would propose a totally different solution:
Have a percpu variable that stores the current SGXLEPUBKEYHASH along
with whatever lock is needed (probably just a mutex). Users of EINIT
will take the mutex, compare the percpu variable to the desired value,
and, if it's different, do WRMSR and update the percpu variable.
This is exactly what I've been suggesting internally: trap EINIT and
check the value and write conditionally.
I think this would be the best starting point.
OK. Assuming we are going to have this percpu variable for
IA32_SGXLEPUBKEYHASHn, I suppose KVM also will update guest's value to
this percpu variable after KVM writes guest's value to hardware MSR? And
host (SGX driver) need to do the same thing (check the value and write
conditionally), correct?
Thanks,
-Kai
/Jarkko
