Hi Stefano,
On 05.12.17 00:06, Stefano Stabellini wrote:
On Mon, 4 Dec 2017, Volodymyr Babchuk wrote:
= Xen command forwarding =
In the code below, it looks like Xen is forwarding everything to OP-TEE.
Are there some commands Xen should avoid forwarding? Should we have a
whitelist or a blacklist?
My code implements whitelists (at least, I hope so :-) ). It forwards
only known requests. If it does not know type of the request, it
returns error back to a caller.
Actually, see below:
+static bool optee_handle_smc(struct cpu_user_regs *regs)
+{
+
+ switch ( get_user_reg(regs, 0) )
+ {
+ case OPTEE_SMC_GET_SHM_CONFIG:
+ return handle_get_shm_config(regs);
+ case OPTEE_SMC_EXCHANGE_CAPABILITIES:
+ return handle_exchange_capabilities(regs);
+ case OPTEE_SMC_CALL_WITH_ARG:
+ return handle_std_call(regs);
+ case OPTEE_SMC_CALL_RETURN_FROM_RPC:
+ return handle_rpc(regs);
+ default:
+ return forward_call(regs);
+ }
+ return false;
+}
In the unknown ("default") case the smc is still forwarded. Am I missing
anything?
No, you are right. It is I who missed to complete this piece of code.
There should be a list of all known OPTEE_SMC_* commands, plus "return
false" in "default" case.
WBR,
--
Volodymyr Babchuk
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