On 7/9/20 3:13 PM, Greg Kurz wrote: > On Thu, 9 Jul 2020 14:21:04 +0200 > Philippe Mathieu-Daudé <phi...@redhat.com> wrote: > >> On 7/9/20 12:55 PM, Greg Kurz wrote: >>> On Thu, 9 Jul 2020 12:18:06 +0200 >>> Philippe Mathieu-Daudé <phi...@redhat.com> wrote: >>> > > [...] > >>>>> >>>>> FYI, PAPR requires all vCPUs to be "stopped" by default. It is up to the >>>>> guest to start them explicitly through an RTAS call. The hypervisor is >>>>> only responsible to start a single vCPU (see spapr_cpu_set_entry_state() >>>>> called from spapr_machine_reset()) to be able to boot the guest. >>>>> >>>>> So I'm not sure to see how that would depend on the accelerator... >>>> >>>> $ qemu-system-ppc64 -M pseries-5.0,accel=tcg -d in_asm >>>> qemu-system-ppc64: warning: TCG doesn't support requested feature, >>>> cap-cfpc=workaround >>>> qemu-system-ppc64: warning: TCG doesn't support requested feature, >>>> cap-sbbc=workaround >>>> qemu-system-ppc64: warning: TCG doesn't support requested feature, >>>> cap-ibs=workaround >>>> qemu-system-ppc64: warning: TCG doesn't support requested feature, >>>> cap-ccf-assist=on >>>> ---------------- >>>> IN: >>>> 0x00000100: 48003f00 b 0x4000 >>>> >>>> ---------------- >>>> IN: >>>> 0x00004000: 7c7f1b78 mr r31, r3 >>>> 0x00004004: 7d6000a6 mfmsr r11 >>>> 0x00004008: 3980a000 li r12, 0xa000 >>>> 0x0000400c: 798c83c6 sldi r12, r12, 0x30 >>>> 0x00004010: 7d6b6378 or r11, r11, r12 >>>> 0x00004014: 7d600164 mtmsrd r11 >>>> ... >>>> >>>> The vCPU doesn't seem stopped to me... >>>> >>>> Am I missing something? >>>> >>> >>> Yeah this is the boot vCPU which is required to be started >>> by the platform as explained above, but if you had more >>> vCPUs the other ones would be stopped until the guest OS >>> asks us to start them. >> >> Ah OK, so we are good :) >> >> The machine simply has to set the 'start-powered-off' flag on >> all vCPUS except the 1st one. >> > > We only want the first vCPU to start when the platform is > fully configured, so I'd rather put 'start-powered-off' on > every body and explicitly power on the first one during > machine reset as we do now.
I meant "we are good" in reference to the beginning of this thread with Thiago and Eduardo: - 'start-powered-off' is a CPU feature (not machine) - machine set the 'start-powered-off' field
