On 2018-11-02 10:01, Andy Lutomirski wrote:
On Fri, Nov 2, 2018 at 9:56 AM Jethro Beekman <jethro@xxxxxxxxxxxx> wrote:On 2018-11-02 09:52, Sean Christopherson wrote:On Fri, Nov 02, 2018 at 04:37:10PM +0000, Jethro Beekman wrote:On 2018-11-02 09:30, Sean Christopherson wrote:... The intended convention for EENTER is to have an ENCLU at the AEX target ... ... to further enforce that the AEX target needs to be ENCLU.Some SGX runtimes may want to use a different AEX target.To what end? Userspace gets no indication as to why the AEX occurred. And if exceptions are getting transfered to userspace the trampoline would effectively be handling only INTR, NMI, #MC and EPC #PF.Various reasons... Userspace may have established an exception handling convention with the enclave (by setting TCS.NSSA > 1) and may want to call EENTER instead of ERESUME.Ugh, I sincerely hope that a future ISA extension lets the kernel return directly back to enclave mode so that AEX events become entirely invisible to user code.
Can you explain how this would work for things like #BR/#DE/#UD that need to be fixed up by code running in the enclave before it can be resumed?
-- Jethro Beekman | Fortanix
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