On Tue, Jan 21, 2025 at 10:01:21PM +0800, Zhao Liu wrote:
> At present, the hpet_cfg is written unconditionally since 40ac17cd56eb
> ("pass info about hpets to seabios.]"), because it concerns ACPI HPET is
> created unconditionally.
>
> But that fact has changed since 51124bbfd2ea ("i386: acpi: Don't build
> HPET ACPI entry if HPET is disabled") and ACPI checks if HPET device
> exists in (hw/i386/acpi-build.c).
>
> Therefore, configure HPET firmware information if and only if HPET is
> enabled.
>
and what is the gain from this change? just a cleanup?
> Signed-off-by: Zhao Liu <[email protected]>
> ---
> Resend:
> * Resend the patch since it was missed on
> https://lore.kernel.org/qemu-devel/.
> ---
> hw/i386/fw_cfg.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/fw_cfg.c b/hw/i386/fw_cfg.c
> index 91bf1df0f2e4..d2cb08715a21 100644
> --- a/hw/i386/fw_cfg.c
> +++ b/hw/i386/fw_cfg.c
> @@ -149,7 +149,14 @@ FWCfgState *fw_cfg_arch_create(MachineState *ms,
> #endif
> fw_cfg_add_i32(fw_cfg, FW_CFG_IRQ0_OVERRIDE, 1);
>
> - fw_cfg_add_bytes(fw_cfg, FW_CFG_HPET, &hpet_cfg, sizeof(hpet_cfg));
> +#ifdef CONFIG_HPET
> + PCMachineState *pcms =
> + (PCMachineState *)object_dynamic_cast(OBJECT(ms), TYPE_PC_MACHINE);
> + if (pcms && pcms->hpet_enabled) {
> + fw_cfg_add_bytes(fw_cfg, FW_CFG_HPET, &hpet_cfg, sizeof(hpet_cfg));
> + }
> +#endif
> +
Hmm. Wouldn't this break cross version migration? I suspect we need
a compat tweak if we do this. Might not be worth it ...
> /* allocate memory for the NUMA channel: one (64bit) word for the number
> * of nodes, one word for each VCPU->node and one word for each node to
> * hold the amount of memory.
> --
> 2.34.1
