i386: clarify that the Q35 machine type implements a P35 chipset

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> Message-Id: <20180830105757.10577-1-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu · Nov 6, 2018 · d471548 · d471548
1 parent e204ac6
commit d471548
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diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
@@ -622,7 +622,15 @@ 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
@@ -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