Re: [PATCH] i386/acpi: restore device paths for pre-5.1 vms

[Igor Mammedov <imammedo@redhat.com>]

On Mon,  1 Mar 2021 22:59:18 +0300
Vitaly Cheptsov <cheptsov@ispras.ru> wrote:

> After fixing the _UID value for the primary PCI root bridge in
> af1b80ae it was discovered that this change updates Windows
> configuration in an incompatible way causing network configuration
> failure unless DHCP is used. More details provided on the list:
> 
> https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg08484.html
> 
> This change reverts the _UID update from 1 to 0 for q35 and i440fx
> VMs before version 5.2 to maintain the original behaviour when
> upgrading.
> 
> Cc: qemu-stable@nongnu.org
> Cc: qemu-devel@nongnu.org
> Reported-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
> Suggested-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Vitaly Cheptsov <cheptsov@ispras.ru>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/i386/acpi-build.c | 4 ++--
>  hw/i386/pc_piix.c    | 2 ++
>  hw/i386/pc_q35.c     | 2 ++
>  include/hw/i386/pc.h | 1 +
>  4 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 31a5f6f4a5..442b4629a9 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1277,7 +1277,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          dev = aml_device("PCI0");
>          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
>          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> -        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> +        aml_append(dev, aml_name_decl("_UID", aml_int(pcmc->pci_root_uid)));
>          aml_append(sb_scope, dev);
>          aml_append(dsdt, sb_scope);
>  
> @@ -1296,7 +1296,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
>          aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
>          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> -        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> +        aml_append(dev, aml_name_decl("_UID", aml_int(pcmc->pci_root_uid)));
>          aml_append(dev, build_q35_osc_method());
>          aml_append(sb_scope, dev);
>          if (mcfg_valid) {
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 2904b40163..46cc951073 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -405,6 +405,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pcmc->default_nic_model = "e1000";
> +    pcmc->pci_root_uid = 0;
>  
>      m->family = "pc_piix";
>      m->desc = "Standard PC (i440FX + PIIX, 1996)";
> @@ -448,6 +449,7 @@ static void pc_i440fx_5_1_machine_options(MachineClass *m)
>      compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
>      compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
>      pcmc->kvmclock_create_always = false;
> +    pcmc->pci_root_uid = 1;
>  }
>  
>  DEFINE_I440FX_MACHINE(v5_1, "pc-i440fx-5.1", NULL,
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index 0a212443aa..53450190f5 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -329,6 +329,7 @@ static void pc_q35_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
>      pcmc->default_nic_model = "e1000e";
> +    pcmc->pci_root_uid = 0;
>  
>      m->family = "pc_q35";
>      m->desc = "Standard PC (Q35 + ICH9, 2009)";
> @@ -375,6 +376,7 @@ static void pc_q35_5_1_machine_options(MachineClass *m)
>      compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
>      compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
>      pcmc->kvmclock_create_always = false;
> +    pcmc->pci_root_uid = 1;
>  }
>  
>  DEFINE_Q35_MACHINE(v5_1, "pc-q35-5.1", NULL,
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index c9d194a5e7..d4c3d73c11 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -105,6 +105,7 @@ struct PCMachineClass {
>      int legacy_acpi_table_size;
>      unsigned acpi_data_size;
>      bool do_not_add_smb_acpi;
> +    int pci_root_uid;
>  
>      /* SMBIOS compat: */
>      bool smbios_defaults;