On 11/02/17 00:14, Volodymyr Babchuk wrote:
Hello,
Hi Volodymyr,
This e-mail is sort of follow-up to the two threads: [1] (my thread about TEE interaction) and [2] (Edgar's thread regarding handling SMC calls in platform_hvc). I want to discuss more broad topic there. Obviously, there are growing number of SMC users and current state of SMC handling in Xen satisfies nobody. My team wants to handle SMCs in secure way, Xilinx wants to forward some calls directly to Secure Monitor, while allowing to handle other in userspace, etc. My proposition is to gather all requirements to SMC (and HVC) handling in one place (e.g. in this mail thread). After we' will have clear picture of what we want, we will be able to develop some solution, that will satisfy us all. At least, I hope so :) Also I want to remind, that there are ARM document called "SMC Calling Convention" [3]. According to it, any aarch64 hypervisor "must implement the Standard Secure and Hypervisor Service calls". At this moment XEN does not conform to this. So, lets get started with the requirements: 0. There are no much difference between SMC and HVC handling (at least according to SMCCC). 1. Hypervisor should at least provide own UUID and version while called by SMC/HVC
Do we need to reserve the UUID for Xen?
2. Hypervisor should forward some calls from dom0 directly to Secure Monitor (Xilinx use case) 3. Hypervisor should virtualize PSCI calls, CPU service calls, ARM architecture service calls, etc. 4. Hypervisor should handle TEE calls in a secure way (e.g. no untrusted handlers in Dom0 userspace). 5. Hypervisor should support multiple TEEs (at least at compilation time). 6. Hypervisor should do this as fast as possible (DRM playback use case). 7. All domains (including dom0) should be handled in the same way.
+1 here. Same path for all domains means less code and you it will get tested more
Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel