On Sat, Jul 20, 2019 at 11:28:48AM +1000, Alexey Kardashevskiy wrote: > The pseries kernel can do either usual prom-init boot or kexec style boot. > We always did the prom-init which relies on the completeness of > the device tree (for example, PCI BARs have to be assigned beforehand) and > the client interface; the system firmware (SLOF) implements this. > > However we can use the kexec style boot as well. To do that, we can skip > loading SLOF and jump straight to the kernel. GPR5==0 (the client > interface entry point, SLOF passes a valid pointer there) tells Linux to > do the kexec boot rather than prom_init so it can proceed to the initramfs. > With few PCI fixes in the guest kernel, it can boot from PCI (via > petitboot, for example). > > This adds a "bios" machine option which controls whether QEMU loads SLOF > or jumps directly to the kernel. When bios==off, this does not copy SLOF > and RTAS into the guest RAM and sets RTAS properties to 0 to bypass > the kexec user space tool which checks for their presence (not for > the values though).
BIOS is sometimes used to refer to any machine's firmware, but it's
also used to refer specifically to PC style BIOS. I think it would be
clearer to be explicit here and call the options "slof" rather than
"bios".
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> include/hw/ppc/spapr.h | 1 +
> hw/ppc/spapr.c | 58 ++++++++++++++++++++++++++++++++----------
> 2 files changed, 45 insertions(+), 14 deletions(-)
>
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index ff82bb8554e1..7f5d7a70d27e 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -160,6 +160,7 @@ struct SpaprMachineState {
> long kernel_size;
> bool kernel_le;
> uint64_t kernel_addr;
> + bool bios_enabled;
> uint32_t initrd_base;
> long initrd_size;
> uint64_t rtc_offset; /* Now used only during incoming migration */
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 6d13d65d8996..81ad6a6f28de 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1116,6 +1116,10 @@ static void spapr_dt_rtas(SpaprMachineState *spapr,
> void *fdt)
> _FDT(fdt_setprop(fdt, rtas, "ibm,lrdr-capacity",
> lrdr_capacity, sizeof(lrdr_capacity)));
>
> + /* These are to make kexec-lite happy */
> + _FDT(fdt_setprop_cell(fdt, rtas, "linux,rtas-base", 0));
> + _FDT(fdt_setprop_cell(fdt, rtas, "rtas-size", 0));
What exactly is kexec-lite and what does it need here?
> spapr_dt_rtas_tokens(fdt, rtas);
> }
>
> @@ -1814,7 +1818,11 @@ static void spapr_machine_reset(MachineState *machine)
> spapr->fdt_blob = fdt;
>
> /* Set up the entry state */
> - spapr_cpu_set_entry_state(first_ppc_cpu, SPAPR_ENTRY_POINT, fdt_addr);
> + if (!spapr->bios_enabled) {
> + spapr_cpu_set_entry_state(first_ppc_cpu, spapr->kernel_addr,
> fdt_addr);
> + } else {
> + spapr_cpu_set_entry_state(first_ppc_cpu, SPAPR_ENTRY_POINT,
> fdt_addr);
> + }
> first_ppc_cpu->env.gpr[5] = 0;
>
> spapr->cas_reboot = false;
> @@ -3031,20 +3039,22 @@ static void spapr_machine_init(MachineState *machine)
> }
> }
>
> - if (bios_name == NULL) {
> - bios_name = FW_FILE_NAME;
> + if (spapr->bios_enabled) {
> + if (bios_name == NULL) {
> + bios_name = FW_FILE_NAME;
> + }
> + filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> + if (!filename) {
> + error_report("Could not find LPAR firmware '%s'", bios_name);
> + exit(1);
> + }
> + fw_size = load_image_targphys(filename, 0, FW_MAX_SIZE);
> + if (fw_size <= 0) {
> + error_report("Could not load LPAR firmware '%s'", filename);
> + exit(1);
> + }
> + g_free(filename);
> }
> - filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> - if (!filename) {
> - error_report("Could not find LPAR firmware '%s'", bios_name);
> - exit(1);
> - }
> - fw_size = load_image_targphys(filename, 0, FW_MAX_SIZE);
> - if (fw_size <= 0) {
> - error_report("Could not load LPAR firmware '%s'", filename);
> - exit(1);
> - }
> - g_free(filename);
>
> /* FIXME: Should register things through the MachineState's qdev
> * interface, this is a legacy from the sPAPREnvironment structure
> @@ -3266,6 +3276,20 @@ static void spapr_set_kernel_addr(Object *obj, Visitor
> *v, const char *name,
> visit_type_uint64(v, name, (uint64_t *)opaque, errp);
> }
>
> +static bool spapr_get_bios_enabled(Object *obj, Error **errp)
> +{
> + SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> +
> + return spapr->bios_enabled;
> +}
> +
> +static void spapr_set_bios_enabled(Object *obj, bool value, Error **errp)
> +{
> + SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> +
> + spapr->bios_enabled = value;
> +}
> +
> static char *spapr_get_ic_mode(Object *obj, Error **errp)
> {
> SpaprMachineState *spapr = SPAPR_MACHINE(obj);
> @@ -3379,6 +3403,12 @@ static void spapr_instance_init(Object *obj)
> " for -kernel is the default",
> NULL);
> spapr->kernel_addr = KERNEL_LOAD_ADDR;
> + object_property_add_bool(obj, "bios", spapr_get_bios_enabled,
> + spapr_set_bios_enabled, NULL);
> + object_property_set_description(obj, "bios", "Conrols whether to load
> bios",
> + NULL);
> + spapr->bios_enabled = true;
> +
> /* The machine class defines the default interrupt controller mode */
> spapr->irq = smc->irq;
> object_property_add_str(obj, "ic-mode", spapr_get_ic_mode,
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
