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Re: [Qemu-ppc] [PATCH RFC] spapr: by-pass SLOF when -kernel is provided
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH RFC] spapr: by-pass SLOF when -kernel is provided |
Date: |
Wed, 6 Jul 2016 11:35:29 +1000 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Tue, Jul 05, 2016 at 04:42:37PM +0200, Laurent Vivier wrote:
> As device-tree is now fully built by QEMU, we don't need SLOF
> anymore if the kernel is provided on the command line.
>
> In this case, don't load SLOF and boot directly into the
> kernel.
>
> This saves at least 5 seconds on the boot sequence.
>
> Signed-off-by: Laurent Vivier <address@hidden>
I'm not comfortable applying this. We actually used to do this ages
ago, but changed to always running through SLOF, and there were
reasons for doing so.
I don't remember exactly what they were, but I think it boiled down to
slight differences in state between booting from SLOF and booting
without SLOF leading to confusing errors from the guest kernel.
> ---
> hw/ppc/spapr.c | 37 ++++++++++++++++++++-----------------
> 1 file changed, 20 insertions(+), 17 deletions(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 7f33a1b..bbdb21d 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1219,8 +1219,11 @@ static void ppc_spapr_reset(void)
> first_ppc_cpu->env.gpr[3] = spapr->fdt_addr;
> first_ppc_cpu->env.gpr[5] = 0;
> first_cpu->halted = 0;
> - first_ppc_cpu->env.nip = SPAPR_ENTRY_POINT;
> -
> + if (machine->kernel_filename) {
> + first_ppc_cpu->env.nip = KERNEL_LOAD_ADDR;
> + } else {
> + first_ppc_cpu->env.nip = SPAPR_ENTRY_POINT;
> + }
> }
>
> static void spapr_create_nvram(sPAPRMachineState *spapr)
> @@ -2023,23 +2026,23 @@ static void ppc_spapr_init(MachineState *machine)
> initrd_base = 0;
> initrd_size = 0;
> }
> + } else {
> + 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);
> }
>
> - 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);
> -
> /* FIXME: Should register things through the MachineState's qdev
> * interface, this is a legacy from the sPAPREnvironment structure
> * which predated MachineState but had a similar function */
--
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
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