Re: [Qemu-devel] [PATCH 6/6] hw/i386/i386: Stop auto-creating lsi53c895a SCSI HBAs

[Paolo Bonzini <pbonzini@redhat.com>]

On 23/01/2017 10:48, Markus Armbruster wrote:
> The PC machines (pc-q35-* pc-i440fx-* pc-* isapc xenfv) automatically
> create lsi53c895a SCSI HBAs and SCSI devices to honor -drive if=scsi.
> For giggles, try -drive if=scsi,bus=25,media=cdrom --- this makes QEMU
> create 25 of them.
> 
> The lsi53c895a is thoroughly obsolete (PCI Ultra2 SCSI, ca. 2000), and
> currently has no maintainer in QEMU.  megasas is a better choice,
> except for old OSes, which lack drivers. virtio-scsi is a much better
> choice when you have a driver, but only (newish) Linux comes with one
> in the box.  There is no good default that works for all guests.
> 
> Instead of supplying the not-so-good default just because we've always
> supplied it, make the user pick, by not creating any SCSI HBAs for
> -drive if=scsi.  The user now needs to create the SCSI HBA himself
> with -device.  The SCSI devices will still be created automatically.
> 
> For backward compatibility, keep the traditional behavior for old
> machine types.

It would print an "orphaned device" message, right?  Could we change
those messages to errors and then drop PC if=scsi support altogether?

Paolo

> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  hw/i386/pc_piix.c    | 15 ++++++++++++++-
>  hw/i386/pc_q35.c     |  7 ++++++-
>  include/hw/i386/pc.h |  3 +++
>  3 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 9f102aa..35e92e4 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -292,7 +292,7 @@ static void pc_init1(MachineState *machine,
>                                   PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
>      }
>  
> -    if (pcmc->pci_enabled) {
> +    if (pcmc->pci_enabled && pcmc->legacy_lsi_hba_auto_create) {
>          pc_pci_device_init(pci_bus);
>      }
>  
> @@ -449,9 +449,12 @@ DEFINE_I440FX_MACHINE(v2_9, "pc-i440fx-2.9", NULL,
>  
>  static void pc_i440fx_2_8_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_9_machine_options(m);
>      m->is_default = 0;
>      m->alias = NULL;
> +    pcmc->legacy_lsi_hba_auto_create = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_8);
>  }
>  
> @@ -472,6 +475,7 @@ DEFINE_I440FX_MACHINE(v2_7, "pc-i440fx-2.7", NULL,
>  static void pc_i440fx_2_6_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_7_machine_options(m);
>      pcmc->legacy_cpu_hotplug = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_6);
> @@ -484,6 +488,7 @@ DEFINE_I440FX_MACHINE(v2_6, "pc-i440fx-2.6", NULL,
>  static void pc_i440fx_2_5_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_6_machine_options(m);
>      pcmc->save_tsc_khz = false;
>      m->legacy_fw_cfg_order = 1;
> @@ -497,6 +502,7 @@ DEFINE_I440FX_MACHINE(v2_5, "pc-i440fx-2.5", NULL,
>  static void pc_i440fx_2_4_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_5_machine_options(m);
>      m->hw_version = "2.4.0";
>      pcmc->broken_reserved_end = true;
> @@ -521,6 +527,7 @@ DEFINE_I440FX_MACHINE(v2_3, "pc-i440fx-2.3", pc_compat_2_3,
>  static void pc_i440fx_2_2_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_3_machine_options(m);
>      m->hw_version = "2.2.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_2);
> @@ -534,6 +541,7 @@ DEFINE_I440FX_MACHINE(v2_2, "pc-i440fx-2.2", pc_compat_2_2,
>  static void pc_i440fx_2_1_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_2_machine_options(m);
>      m->hw_version = "2.1.0";
>      m->default_display = NULL;
> @@ -550,6 +558,7 @@ DEFINE_I440FX_MACHINE(v2_1, "pc-i440fx-2.1", pc_compat_2_1,
>  static void pc_i440fx_2_0_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_1_machine_options(m);
>      m->hw_version = "2.0.0";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_0);
> @@ -582,6 +591,7 @@ DEFINE_I440FX_MACHINE(v2_0, "pc-i440fx-2.0", pc_compat_2_0,
>  static void pc_i440fx_1_7_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_2_0_machine_options(m);
>      m->hw_version = "1.7.0";
>      m->default_machine_opts = NULL;
> @@ -599,6 +609,7 @@ DEFINE_I440FX_MACHINE(v1_7, "pc-i440fx-1.7", pc_compat_1_7,
>  static void pc_i440fx_1_6_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_1_7_machine_options(m);
>      m->hw_version = "1.6.0";
>      m->rom_file_has_mr = false;
> @@ -858,6 +869,7 @@ DEFINE_I440FX_MACHINE(v0_14, "pc-0.14", pc_compat_1_2,
>  static void pc_i440fx_0_13_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_i440fx_0_14_machine_options(m);
>      m->hw_version = "0.13";
>      SET_MACHINE_COMPAT(m, PC_COMPAT_0_13);
> @@ -1084,6 +1096,7 @@ void igd_passthrough_isa_bridge_create(PCIBus *bus, uint16_t gpu_dev_id)
>  static void isapc_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      m->desc = "ISA-only PC";
>      m->max_cpus = 1;
>      m->option_rom_has_mr = true;
> diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> index dd792a8..571565d 100644
> --- a/hw/i386/pc_q35.c
> +++ b/hw/i386/pc_q35.c
> @@ -266,7 +266,7 @@ static void pc_q35_init(MachineState *machine)
>      /* the rest devices to which pci devfn is automatically assigned */
>      pc_vga_init(isa_bus, host_bus);
>      pc_nic_init(isa_bus, host_bus);
> -    if (pcmc->pci_enabled) {
> +    if (pcmc->pci_enabled && pcmc->legacy_lsi_hba_auto_create) {
>          pc_pci_device_init(host_bus);
>      }
>  
> @@ -312,8 +312,11 @@ DEFINE_Q35_MACHINE(v2_9, "pc-q35-2.9", NULL,
>  
>  static void pc_q35_2_8_machine_options(MachineClass *m)
>  {
> +    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_q35_2_9_machine_options(m);
>      m->alias = NULL;
> +    pcmc->legacy_lsi_hba_auto_create = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_8);
>  }
>  
> @@ -333,6 +336,7 @@ DEFINE_Q35_MACHINE(v2_7, "pc-q35-2.7", NULL,
>  static void pc_q35_2_6_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_q35_2_7_machine_options(m);
>      pcmc->legacy_cpu_hotplug = true;
>      SET_MACHINE_COMPAT(m, PC_COMPAT_2_6);
> @@ -356,6 +360,7 @@ DEFINE_Q35_MACHINE(v2_5, "pc-q35-2.5", NULL,
>  static void pc_q35_2_4_machine_options(MachineClass *m)
>  {
>      PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
> +
>      pc_q35_2_5_machine_options(m);
>      m->hw_version = "2.4.0";
>      pcmc->broken_reserved_end = true;
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index 230e9e7..991b87b 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -152,6 +152,9 @@ struct PCMachineClass {
>      bool save_tsc_khz;
>      /* generate legacy CPU hotplug AML */
>      bool legacy_cpu_hotplug;
> +
> +    /* Whether to auto-create lsi53c895a SCSI HBAs */
> +    bool legacy_lsi_hba_auto_create;
>  };
>  
>  #define TYPE_PC_MACHINE "generic-pc-machine"
>