diff options
| -rw-r--r-- | drivers/vfio/pci/vfio_pci.c | 67 |
1 files changed, 63 insertions, 4 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 7053110e4734..25aef05b8692 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -25,6 +25,7 @@ #include <linux/types.h> #include <linux/uaccess.h> #include <linux/vfio.h> +#include <linux/vgaarb.h> #include "vfio_pci_private.h" @@ -54,6 +55,50 @@ static inline bool vfio_vga_disabled(void) #endif } +/* + * Our VGA arbiter participation is limited since we don't know anything + * about the device itself. However, if the device is the only VGA device + * downstream of a bridge and VFIO VGA support is disabled, then we can + * safely return legacy VGA IO and memory as not decoded since the user + * has no way to get to it and routing can be disabled externally at the + * bridge. + */ +static unsigned int vfio_pci_set_vga_decode(void *opaque, bool single_vga) +{ + struct vfio_pci_device *vdev = opaque; + struct pci_dev *tmp = NULL, *pdev = vdev->pdev; + unsigned char max_busnr; + unsigned int decodes; + + if (single_vga || !vfio_vga_disabled() || pci_is_root_bus(pdev->bus)) + return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM | + VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + + max_busnr = pci_bus_max_busnr(pdev->bus); + decodes = VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM; + + while ((tmp = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, tmp)) != NULL) { + if (tmp == pdev || + pci_domain_nr(tmp->bus) != pci_domain_nr(pdev->bus) || + pci_is_root_bus(tmp->bus)) + continue; + + if (tmp->bus->number >= pdev->bus->number && + tmp->bus->number <= max_busnr) { + pci_dev_put(tmp); + decodes |= VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM; + break; + } + } + + return decodes; +} + +static inline bool vfio_pci_is_vga(struct pci_dev *pdev) +{ + return (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA; +} + static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev); static int vfio_pci_enable(struct vfio_pci_device *vdev) @@ -108,7 +153,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) } else vdev->msix_bar = 0xFF; - if (!vfio_vga_disabled() && (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA) + if (!vfio_vga_disabled() && vfio_pci_is_vga(pdev)) vdev->has_vga = true; return 0; @@ -900,6 +945,12 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) kfree(vdev); } + if (vfio_pci_is_vga(pdev)) { + vga_client_register(pdev, vdev, NULL, vfio_pci_set_vga_decode); + vga_set_legacy_decoding(pdev, + vfio_pci_set_vga_decode(vdev, false)); + } + return ret; } @@ -908,9 +959,17 @@ static void vfio_pci_remove(struct pci_dev *pdev) struct vfio_pci_device *vdev; vdev = vfio_del_group_dev(&pdev->dev); - if (vdev) { - iommu_group_put(pdev->dev.iommu_group); - kfree(vdev); + if (!vdev) + return; + + iommu_group_put(pdev->dev.iommu_group); + kfree(vdev); + + if (vfio_pci_is_vga(pdev)) { + vga_client_register(pdev, NULL, NULL, NULL); + vga_set_legacy_decoding(pdev, + VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM | + VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM); } } |