Hi Dongjiu Geng, On 28/08/17 11:38, Dongjiu Geng wrote: > ARMv8.2 adds a new bit HCR_EL2.TEA which controls to > route synchronous external aborts to EL2, and adds a > trap control bit HCR_EL2.TERR which controls to > trap all Non-secure EL1&0 error record accesses to EL2. > > This patch enables the two bits for the guest OS. > when an synchronous abort is generated in the guest OS, > it will trap to EL3 firmware, EL3 firmware will check the > HCR_EL2.TEA value to decide to jump to hypervisor or host > OS. (This is what you are using this for, the patch has nothing to do with EL3.) > Enabling HCR_EL2.TERR makes error record access > from guest trap to EL2. KVM already handles external aborts from lower exception levels, no more work needs doing for TEA. What happens when a guest access the RAS-Error-Record registers? Before we can set HCR_EL2.TERR I think we need to add some minimal emulation for the registers it traps. Most of them should be RAZ/WI, so it should be straightforward. (I think KVMs default is to emulate an undef for unknown traps). Eventually we will want to back this with a page of memory that lets Qemu/kvmtool configure what the guest can see. (i.e. the emulated machine's errors for kernel-first handling.) Thanks, James
