Re: [Qemu-devel] [PATCH] i386: clarify that the Q35 machine type implements a P35 chipset

["Daniel P. Berrangé" <berrange@redhat.com>]

Ping - it has 2 reviews, but never made it into the i386 maintainers
tree / pull request. Can someone queue this patch for merge.

On Thu, Aug 30, 2018 at 11:57:57AM +0100, Daniel P. Berrangé wrote:
> The 'q35' machine type implements an Intel Series 3 chipset,
> of which there are several variants:
> 
>   https://www.intel.com/Assets/PDF/datasheet/316966.pdf
> 
> The key difference between the 82P35 MCH ('p35', PCI device ID 0x29c0)
> and 82Q35 GMCH ('q35', PCI device ID 0x29b0) variants is that the latter
> has an integrated graphics adapter. QEMU does not implement integrated
> graphics, so uses the PCI ID for the 82P35 chipset, despite calling the
> machine type 'q35'. Thus we rename the PCI device ID constant to reflect
> reality, to avoid confusing future developers. The new name more closely
> matches what pci.ids reports it to be:
> 
> $ grep  P35 /usr/share/hwdata/pci.ids  | grep 29
> 	29c0  82G33/G31/P35/P31 Express DRAM Controller
> 	29c1  82G33/G31/P35/P31 Express PCI Express Root Port
> 	29c4  82G33/G31/P35/P31 Express MEI Controller
> 	29c5  82G33/G31/P35/P31 Express MEI Controller
> 	29c6  82G33/G31/P35/P31 Express PT IDER Controller
> 	29c7  82G33/G31/P35/P31 Express Serial KT Controller
> 
> $ grep  Q35 /usr/share/hwdata/pci.ids  | grep 29
> 	29b0  82Q35 Express DRAM Controller
> 	29b1  82Q35 Express PCI Express Root Port
> 	29b2  82Q35 Express Integrated Graphics Controller
> 	29b3  82Q35 Express Integrated Graphics Controller
> 	29b4  82Q35 Express MEI Controller
> 	29b5  82Q35 Express MEI Controller
> 	29b6  82Q35 Express PT IDER Controller
> 	29b7  82Q35 Express Serial KT Controller
> 
> Arguably the QEMU machine type should be named 'p35'. At this point in
> time, however, it is not worth the churn for management applications &
> documentation to worry about renaming it.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  hw/pci-host/q35.c        | 10 +++++++++-
>  include/hw/pci/pci_ids.h |  2 +-
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
> index 02f9576588..0a056d6aea 100644
> --- a/hw/pci-host/q35.c
> +++ b/hw/pci-host/q35.c
> @@ -618,7 +618,15 @@ static void mch_class_init(ObjectClass *klass, void *data)
>      dc->desc = "Host bridge";
>      dc->vmsd = &vmstate_mch;
>      k->vendor_id = PCI_VENDOR_ID_INTEL;
> -    k->device_id = PCI_DEVICE_ID_INTEL_Q35_MCH;
> +    /*
> +     * The 'q35' machine type implements an Intel Series 3 chipset,
> +     * of which there are several variants. The key difference between
> +     * the 82P35 MCH ('p35') and 82Q35 GMCH ('q35') variants is that
> +     * the latter has an integrated graphics adapter. QEMU does not
> +     * implement integrated graphics, so uses the PCI ID for the 82P35
> +     * chipset.
> +     */
> +    k->device_id = PCI_DEVICE_ID_INTEL_P35_MCH;
>      k->revision = MCH_HOST_BRIDGE_REVISION_DEFAULT;
>      k->class_id = PCI_CLASS_BRIDGE_HOST;
>      /*
> diff --git a/include/hw/pci/pci_ids.h b/include/hw/pci/pci_ids.h
> index 63acc722a9..eeb33018ad 100644
> --- a/include/hw/pci/pci_ids.h
> +++ b/include/hw/pci/pci_ids.h
> @@ -255,7 +255,7 @@
>  #define PCI_DEVICE_ID_INTEL_82801I_EHCI2 0x293c
>  #define PCI_DEVICE_ID_INTEL_82599_SFP_VF 0x10ed
>  
> -#define PCI_DEVICE_ID_INTEL_Q35_MCH      0x29c0
> +#define PCI_DEVICE_ID_INTEL_P35_MCH      0x29c0
>  
>  #define PCI_VENDOR_ID_XEN                0x5853
>  #define PCI_DEVICE_ID_XEN_PLATFORM       0x0001
> -- 
> 2.17.1
> 

Regards,
Daniel
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