On 15/11/2019 11.20, Janosch Frank wrote: > On 11/15/19 11:04 AM, Thomas Huth wrote: >> On 24/10/2019 13.40, Janosch Frank wrote: >>> If the host initialized the Ultravisor, we can set stfle bit 161 >>> (protected virtual IPL enhancements facility), which indicates, that >>> the IPL subcodes 8, 9 and are valid. These subcodes are used by a >>> normal guest to set/retrieve a IPIB of type 5 and transition into >>> protected mode. >>> >>> Once in protected mode, the VM will loose the facility bit, as each >> >> So should the bit be cleared in the host code again? ... I don't see >> this happening in this patch? >> >> Thomas > > No, KVM doesn't report stfle facilities in protected mode and we would > need to add it again in normal mode so just clearing it would be > pointless. In protected mode 8-10 do not intercept, so there's nothing > we need to do. Ah, ok, that's what I've missed. Maybe replace "the VM will loose the facility bit" with "the ultravisor will conceal the facility bit" ? Thomas
