vfio-pci: Add support for VGA region access

PCI defines display class VGA regions at I/O port address 0x3b0, 0x3c0 and MMIO address 0xa0000. As these are non-overlapping, we can ignore the I/O port vs MMIO difference and expose them both in a single region. We make use of the VGA arbiter around each access to configure chipset access as necessary.

Alex Williamson committed 13 years ago

Commit 84237a81 parent 2dd11945 files · +102 −0Browse files

Unified · Split

5 files

drivers/vfio/pci/Kconfig +10 −0
drivers/vfio/pci/vfio_pci.c +18 −0
drivers/vfio/pci/vfio_pci_private.h +4 −0
drivers/vfio/pci/vfio_pci_rdwr.c +61 −0
include/uapi/linux/vfio.h +9 −0

drivers/vfio/pci/Kconfig+10−0

@@ -6,3 +6,13 @@ config VFIO_PCI · 5 unmodified lines
6	6	use of PCI drivers using the VFIO framework.
7	7
8	8	If you don't know what to do here, say N.
	9	+
	10	+config VFIO_PCI_VGA
	11	+ bool "VFIO PCI support for VGA devices"
	12	+ depends on VFIO_PCI && X86 && VGA_ARB && EXPERIMENTAL
	13	+ help
	14	+ Support for VGA extension to VFIO PCI. This exposes an additional
	15	+ region on VGA devices for accessing legacy VGA addresses used by
	16	+ BIOS and generic video drivers.
	17	+
	18	+ If you don't know what to do here, say N.

drivers/vfio/pci/vfio_pci.c+18−0

@@ -84,6 +84,11 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) · 83 unmodified lines
84	84	} else
85	85	vdev->msix_bar = 0xFF;
86	86
	87	+#ifdef CONFIG_VFIO_PCI_VGA
	88	+ if ((pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA)
	89	+ vdev->has_vga = true;
	90	+#endif
	91	+
87	92	return 0;
88	93	}
89	94
@@ -285,6 +290,16 @@ static long vfio_pci_ioctl(void *device_data, · 195 unmodified lines
285	290	info.flags = VFIO_REGION_INFO_FLAG_READ;
286	291	break;
287	292	}
	293	+ case VFIO_PCI_VGA_REGION_INDEX:
	294	+ if (!vdev->has_vga)
	295	+ return -EINVAL;
	296	+
	297	+ info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);
	298	+ info.size = 0xc0000;
	299	+ info.flags = VFIO_REGION_INFO_FLAG_READ \|
	300	+ VFIO_REGION_INFO_FLAG_WRITE;
	301	+
	302	+ break;
288	303	default:
289	304	return -EINVAL;
290	305	}
@@ -386,6 +401,9 @@ static ssize_t vfio_pci_rw(void device_data, char __user buf, · 95 unmodified lines
386	401
387	402	case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX:
388	403	return vfio_pci_bar_rw(vdev, buf, count, ppos, iswrite);
	404	+
	405	+ case VFIO_PCI_VGA_REGION_INDEX:
	406	+ return vfio_pci_vga_rw(vdev, buf, count, ppos, iswrite);
389	407	}
390	408
391	409	return -EINVAL;

drivers/vfio/pci/vfio_pci_private.h+4−0

@@ -53,6 +53,7 @@ struct vfio_pci_device { · 52 unmodified lines
53	53	bool reset_works;
54	54	bool extended_caps;
55	55	bool bardirty;
	56	+ bool has_vga;
56	57	struct pci_saved_state *pci_saved_state;
57	58	atomic_t refcnt;
58	59	};
@@ -77,6 +78,9 @@ extern ssize_t vfio_pci_config_rw(struct vfio_pci_device *vdev, · 18 unmodified lines
77	78	extern ssize_t vfio_pci_bar_rw(struct vfio_pci_device vdev, char __user buf,
78	79	size_t count, loff_t *ppos, bool iswrite);
79	80
	81	+extern ssize_t vfio_pci_vga_rw(struct vfio_pci_device vdev, char __user buf,
	82	+ size_t count, loff_t *ppos, bool iswrite);
	83	+
80	84	extern int vfio_pci_init_perm_bits(void);
81	85	extern void vfio_pci_uninit_perm_bits(void);
82	86

drivers/vfio/pci/vfio_pci_rdwr.c+61−0

@@ -17,6 +17,7 @@ · 16 unmodified lines
17	17	#include <linux/pci.h>
18	18	#include <linux/uaccess.h>
19	19	#include <linux/io.h>
	20	+#include <linux/vgaarb.h>
20	21
21	22	#include "vfio_pci_private.h"
22	23
@@ -175,3 +176,63 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_device vdev, char __user buf, · 152 unmodified lines
175	176
176	177	return done;
177	178	}
	179	+
	180	+ssize_t vfio_pci_vga_rw(struct vfio_pci_device vdev, char __user buf,
	181	+ size_t count, loff_t *ppos, bool iswrite)
	182	+{
	183	+ int ret;
	184	+ loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
	185	+ void __iomem *iomem = NULL;
	186	+ unsigned int rsrc;
	187	+ bool is_ioport;
	188	+ ssize_t done;
	189	+
	190	+ if (!vdev->has_vga)
	191	+ return -EINVAL;
	192	+
	193	+ switch (pos) {
	194	+ case 0xa0000 ... 0xbffff:
	195	+ count = min(count, (size_t)(0xc0000 - pos));
	196	+ iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1);
	197	+ off = pos - 0xa0000;
	198	+ rsrc = VGA_RSRC_LEGACY_MEM;
	199	+ is_ioport = false;
	200	+ break;
	201	+ case 0x3b0 ... 0x3bb:
	202	+ count = min(count, (size_t)(0x3bc - pos));
	203	+ iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1);
	204	+ off = pos - 0x3b0;
	205	+ rsrc = VGA_RSRC_LEGACY_IO;
	206	+ is_ioport = true;
	207	+ break;
	208	+ case 0x3c0 ... 0x3df:
	209	+ count = min(count, (size_t)(0x3e0 - pos));
	210	+ iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1);
	211	+ off = pos - 0x3c0;
	212	+ rsrc = VGA_RSRC_LEGACY_IO;
	213	+ is_ioport = true;
	214	+ break;
	215	+ default:
	216	+ return -EINVAL;
	217	+ }
	218	+
	219	+ if (!iomem)
	220	+ return -ENOMEM;
	221	+
	222	+ ret = vga_get_interruptible(vdev->pdev, rsrc);
	223	+ if (ret) {
	224	+ is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
	225	+ return ret;
	226	+ }
	227	+
	228	+ done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite);
	229	+
	230	+ vga_put(vdev->pdev, rsrc);
	231	+
	232	+ is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
	233	+
	234	+ if (done >= 0)
	235	+ *ppos += done;
	236	+
	237	+ return done;
	238	+}

include/uapi/linux/vfio.h+9−0

@@ -303,6 +303,15 @@ enum { · 302 unmodified lines
303	303	VFIO_PCI_BAR5_REGION_INDEX,
304	304	VFIO_PCI_ROM_REGION_INDEX,
305	305	VFIO_PCI_CONFIG_REGION_INDEX,
	306	+ /*
	307	+ * Expose VGA regions defined for PCI base class 03, subclass 00.
	308	+ * This includes I/O port ranges 0x3b0 to 0x3bb and 0x3c0 to 0x3df
	309	+ * as well as the MMIO range 0xa0000 to 0xbffff. Each implemented
	310	+ * range is found at it's identity mapped offset from the region
	311	+ * offset, for example 0x3b0 is region_info.offset + 0x3b0. Areas
	312	+ * between described ranges are unimplemented.
	313	+ */
	314	+ VFIO_PCI_VGA_REGION_INDEX,
306	315	VFIO_PCI_NUM_REGIONS
307	316	};
308	317

vfio-pci: Add support for VGA region access

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