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vfio/igd: Move LPC bridge initialization to a separate function

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A new option will soon be introduced to decouple the LPC bridge/Host
bridge ID quirk from legacy mode. To prepare for this, move the LPC
bridge initialization into a separate function.

Signed-off-by: Tomita Moeko <tomitamoeko@gmail.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Corvin Köhne <c.koehne@beckhoff.com>
Link: https://lore.kernel.org/qemu-devel/20250306180131.32970-5-tomitamoeko@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Tomita Moeko 2025-03-07 02:01:24 +08:00 • committed by Cédric Le Goater
parent ae9d9ec4a6
commit eabaa7b468
1 changed files with 70 additions and 52 deletions
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122
hw/vfio/igd.c
View file

@ -351,6 +351,72 @@ static int vfio_pci_igd_lpc_init(VFIOPCIDevice *vdev,
return ret;
}
static bool vfio_pci_igd_setup_lpc_bridge(VFIOPCIDevice *vdev, Error **errp)
{
g_autofree struct vfio_region_info *host = NULL;
g_autofree struct vfio_region_info *lpc = NULL;
PCIDevice *lpc_bridge;
int ret;
/*
* Copying IDs or creating new devices are not supported on hotplug
*/
if (vdev->pdev.qdev.hotplugged) {
error_setg(errp, "IGD LPC is not supported on hotplugged device");
return false;
}
/*
* We need to create an LPC/ISA bridge at PCI bus address 00:1f.0 that we
* can stuff host values into, so if there's already one there and it's not
* one we can hack on, this quirk is no-go. Sorry Q35.
*/
lpc_bridge = pci_find_device(pci_device_root_bus(&vdev->pdev),
0, PCI_DEVFN(0x1f, 0));
if (lpc_bridge && !object_dynamic_cast(OBJECT(lpc_bridge),
"vfio-pci-igd-lpc-bridge")) {
error_setg(errp,
"Cannot create LPC bridge due to existing device at 1f.0");
return false;
}
/*
* Check whether we have all the vfio device specific regions to
* support LPC quirk (added in Linux v4.6).
*/
ret = vfio_get_dev_region_info(&vdev->vbasedev,
VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG, &lpc);
if (ret) {
error_setg(errp, "IGD LPC bridge access is not supported by kernel");
return false;
}
ret = vfio_get_dev_region_info(&vdev->vbasedev,
VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG, &host);
if (ret) {
error_setg(errp, "IGD host bridge access is not supported by kernel");
return false;
}
/* Create/modify LPC bridge */
ret = vfio_pci_igd_lpc_init(vdev, lpc);
if (ret) {
error_setg(errp, "Failed to create/modify LPC bridge for IGD");
return false;
}
/* Stuff some host values into the VM PCI host bridge */
ret = vfio_pci_igd_host_init(vdev, host);
if (ret) {
error_setg(errp, "Failed to modify host bridge for IGD");
return false;
}
return true;
}
#define IGD_GGC_MMIO_OFFSET 0x108040
#define IGD_BDSM_MMIO_OFFSET 0x1080C0
@ -419,9 +485,6 @@ void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr)
void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
{
g_autofree struct vfio_region_info *rom = NULL;
g_autofree struct vfio_region_info *host = NULL;
g_autofree struct vfio_region_info *lpc = NULL;
PCIDevice *lpc_bridge;
int ret, gen;
uint64_t gms_size;
uint64_t *bdsm_size;
@ -440,20 +503,6 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
return;
}
/*
* We need to create an LPC/ISA bridge at PCI bus address 00:1f.0 that we
* can stuff host values into, so if there's already one there and it's not
* one we can hack on, legacy mode is no-go. Sorry Q35.
*/
lpc_bridge = pci_find_device(pci_device_root_bus(&vdev->pdev),
0, PCI_DEVFN(0x1f, 0));
if (lpc_bridge && !object_dynamic_cast(OBJECT(lpc_bridge),
"vfio-pci-igd-lpc-bridge")) {
error_report("IGD device %s cannot support legacy mode due to existing "
"devices at address 1f.0", vdev->vbasedev.name);
return;
}
/*
* IGD is not a standard, they like to change their specs often. We
* only attempt to support back to SandBridge and we hope that newer
@ -490,28 +539,6 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
return;
}
/*
* Check whether we have all the vfio device specific regions to
* support legacy mode (added in Linux v4.6). If not, bail.
*/
ret = vfio_get_dev_region_info(&vdev->vbasedev,
VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG, &host);
if (ret) {
error_report("IGD device %s does not support host bridge access,"
"legacy mode disabled", vdev->vbasedev.name);
return;
}
ret = vfio_get_dev_region_info(&vdev->vbasedev,
VFIO_REGION_TYPE_PCI_VENDOR_TYPE | PCI_VENDOR_ID_INTEL,
VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG, &lpc);
if (ret) {
error_report("IGD device %s does not support LPC bridge access,"
"legacy mode disabled", vdev->vbasedev.name);
return;
}
gmch = vfio_pci_read_config(&vdev->pdev, IGD_GMCH, 4);
/*
@ -533,19 +560,10 @@ void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr)
return;
}
/* Create our LPC/ISA bridge */
ret = vfio_pci_igd_lpc_init(vdev, lpc);
if (ret) {
error_report("IGD device %s failed to create LPC bridge, "
"legacy mode disabled", vdev->vbasedev.name);
return;
}
/* Stuff some host values into the VM PCI host bridge */
ret = vfio_pci_igd_host_init(vdev, host);
if (ret) {
error_report("IGD device %s failed to modify host bridge, "
"legacy mode disabled", vdev->vbasedev.name);
/* Setup LPC bridge / Host bridge PCI IDs */
if (!vfio_pci_igd_setup_lpc_bridge(vdev, &err)) {
error_append_hint(&err, "IGD legacy mode disabled\n");
error_report_err(err);
return;
}