On Tue, Jun 06, 2023 at 09:49:37PM -0500, Suravee Suthikulpanit wrote:
> Into a helper function pc_machine_init_smbios() in preparation for
> subsequent code to upgrade default SMBIOS entry point type.
>
> Then, call the helper function from the pc_machine_initfn() to eliminate
> duplicate code in pc_q35.c and pc_pixx.c. However, this changes the
> ordering of when the smbios_set_defaults() is called to before
> pc_machine_set_smbios_ep() (i.e. before handling the user specified
> QEMU option "-M ...,smbios-entry-point-type=[32|64]" to override
> the default type.)
>
> Therefore, also call the helper function in pc_machine_set_smbios_ep()
> to update the defaults.
This is unsafe - smbios_set_defaults is only intended to be called
once. Calling it twice leads to a SEGV due to double-free
$ ./build/qemu-system-x86_64 -machine pc,smbios-entry-point-type=64 -smbios
file=/tmp/smbios_entry_point
Segmentation fault (core dumped)
IMHO we should just not do this refactoring. The existing duplicated
code is not a significant burden, and thus is better than having to
workaround calling pc_machine_set_smbios_ep too early in startup.
>
> There is no functional change.
>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
> ---
> hw/i386/pc.c | 24 +++++++++++++++++++++++-
> hw/i386/pc_piix.c | 9 ---------
> hw/i386/pc_q35.c | 8 --------
> 3 files changed, 23 insertions(+), 18 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index bb62c994fa..b720dc67b6 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1756,6 +1756,22 @@ static void
> pc_machine_set_default_bus_bypass_iommu(Object *obj, bool value,
> pcms->default_bus_bypass_iommu = value;
> }
>
> +static void pc_machine_init_smbios(PCMachineState *pcms)
> +{
> + PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
> + MachineClass *mc = MACHINE_GET_CLASS(pcms);
> +
> + if (!pcmc->smbios_defaults) {
> + return;
> + }
> +
> + /* These values are guest ABI, do not change */
> + smbios_set_defaults("QEMU", mc->desc,
> + mc->name, pcmc->smbios_legacy_mode,
> + pcmc->smbios_uuid_encoded,
> + pcms->smbios_entry_point_type);
> +}
> +
> static void pc_machine_get_smbios_ep(Object *obj, Visitor *v, const char
> *name,
> void *opaque, Error **errp)
> {
> @@ -1768,9 +1784,14 @@ static void pc_machine_get_smbios_ep(Object *obj,
> Visitor *v, const char *name,
> static void pc_machine_set_smbios_ep(Object *obj, Visitor *v, const char
> *name,
> void *opaque, Error **errp)
> {
> + SmbiosEntryPointType ep_type;
> PCMachineState *pcms = PC_MACHINE(obj);
>
> - visit_type_SmbiosEntryPointType(v, name, &pcms->smbios_entry_point_type,
> errp);
> + if (!visit_type_SmbiosEntryPointType(v, name, &ep_type, errp)) {
> + return;
> + }
> + pcms->smbios_entry_point_type = ep_type;
> + pc_machine_init_smbios(pcms);
> }
>
> static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
> @@ -1878,6 +1899,7 @@ static void pc_machine_initfn(Object *obj)
> object_property_add_alias(OBJECT(pcms), "pcspk-audiodev",
> OBJECT(pcms->pcspk), "audiodev");
> cxl_machine_init(obj, &pcms->cxl_devices_state);
> + pc_machine_init_smbios(pcms);
> }
>
> int pc_machine_kvm_type(MachineState *machine, const char *kvm_type)
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index d5b0dcd1fe..da6ba4eeb4 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -198,15 +198,6 @@ static void pc_init1(MachineState *machine,
>
> pc_guest_info_init(pcms);
>
> - if (pcmc->smbios_defaults) {
> - MachineClass *mc = MACHINE_GET_CLASS(machine);
> - /* These values are guest ABI, do not change */
> - smbios_set_defaults("QEMU", mc->desc,
> - mc->name, pcmc->smbios_legacy_mode,
> - pcmc->smbios_uuid_encoded,
> - pcms->smbios_entry_point_type);
> - }
> -
> /* allocate ram and load rom/bios */
> if (!xen_enabled()) {
> pc_memory_init(pcms, system_memory, rom_memory, hole64_size);
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 6155427e48..a58cd1d3ea 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -198,14 +198,6 @@ static void pc_q35_init(MachineState *machine)
>
> pc_guest_info_init(pcms);
>
> - if (pcmc->smbios_defaults) {
> - /* These values are guest ABI, do not change */
> - smbios_set_defaults("QEMU", mc->desc,
> - mc->name, pcmc->smbios_legacy_mode,
> - pcmc->smbios_uuid_encoded,
> - pcms->smbios_entry_point_type);
> - }
> -
> /* create pci host bus */
> q35_host = Q35_HOST_DEVICE(qdev_new(TYPE_Q35_HOST_DEVICE));
>
> --
> 2.34.1
>
With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
