On 6/7/19, 7:59 AM, " Ali Saidi" <alisaidi@xxxxxxxxxx> wrote: On 6/5/19, 7:20 AM, "Will Deacon" <will.deacon@xxxxxxx> wrote: On Tue, Jun 04, 2019 at 08:30:57PM +0000, Ali Saidi wrote: > AWS Graviton based systems provide an Arm SMC call in the vendor defined > hypervisor region to read random numbers from a HW TRNG and return them to the > guest. > > We've observed slower guest boot and especially reboot times due to lack of > entropy and providing access to a TRNG is meant to address this. Curious, but why this over something like virtio-rng? This interface allows us to provide the functionality from both EL2 and EL3 and support multiple different types of our instances which we unfortunately can't do with virt-io. Will, Any additional comments? Mark, Do you know when you'll have a chance to rebase arm64/smccc-cleanup? Thanks, Ali