vfio/pci: Split quirks to a separate file

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 887 insertions, 0 deletions

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
new file mode 100644
index 0000000000..1f9a8096a1
--- /dev/null
+++ b/hw/vfio/pci-quirks.c
@@ -0,0 +1,887 @@
+/*
+ * device quirks for PCI devices
+ *
+ * Copyright Red Hat, Inc. 2012-2015
+ *
+ * Authors:
+ *  Alex Williamson <alex.williamson@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "pci.h"
+#include "trace.h"
+#include "qemu/range.h"
+
+/*
+ * List of device ids/vendor ids for which to disable
+ * option rom loading. This avoids the guest hangs during rom
+ * execution as noticed with the BCM 57810 card for lack of a
+ * more better way to handle such issues.
+ * The  user can still override by specifying a romfile or
+ * rombar=1.
+ * Please see https://bugs.launchpad.net/qemu/+bug/1284874
+ * for an analysis of the 57810 card hang. When adding
+ * a new vendor id/device id combination below, please also add
+ * your card/environment details and information that could
+ * help in debugging to the bug tracking this issue
+ */
+static const VFIORomBlacklistEntry romblacklist[] = {
+    /* Broadcom BCM 57810 */
+    { 0x14e4, 0x168e }
+};
+
+bool vfio_blacklist_opt_rom(VFIOPCIDevice *vdev)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    uint16_t vendor_id, device_id;
+    int count = 0;
+
+    vendor_id = pci_get_word(pdev->config + PCI_VENDOR_ID);
+    device_id = pci_get_word(pdev->config + PCI_DEVICE_ID);
+
+    while (count < ARRAY_SIZE(romblacklist)) {
+        if (romblacklist[count].vendor_id == vendor_id &&
+            romblacklist[count].device_id == device_id) {
+                return true;
+        }
+        count++;
+    }
+
+    return false;
+}
+
+/*
+ * Device specific quirks
+ */
+
+/* Is range1 fully contained within range2?  */
+static bool vfio_range_contained(uint64_t first1, uint64_t len1,
+                                 uint64_t first2, uint64_t len2) {
+    return (first1 >= first2 && first1 + len1 <= first2 + len2);
+}
+
+static bool vfio_flags_enabled(uint8_t flags, uint8_t mask)
+{
+    return (mask && (flags & mask) == mask);
+}
+
+static uint64_t vfio_generic_window_quirk_read(void *opaque,
+                                               hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    uint64_t data;
+
+    if (vfio_flags_enabled(quirk->data.flags, quirk->data.read_flags) &&
+        ranges_overlap(addr, size,
+                       quirk->data.data_offset, quirk->data.data_size)) {
+        hwaddr offset = addr - quirk->data.data_offset;
+
+        if (!vfio_range_contained(addr, size, quirk->data.data_offset,
+                                  quirk->data.data_size)) {
+            hw_error("%s: window data read not fully contained: %s",
+                     __func__, memory_region_name(&quirk->mem));
+        }
+
+        data = vfio_pci_read_config(&vdev->pdev,
+                                    quirk->data.address_val + offset, size);
+
+        trace_vfio_generic_window_quirk_read(memory_region_name(&quirk->mem),
+                                             vdev->vbasedev.name,
+                                             quirk->data.bar,
+                                             addr, size, data);
+    } else {
+        data = vfio_region_read(&vdev->bars[quirk->data.bar].region,
+                                addr + quirk->data.base_offset, size);
+    }
+
+    return data;
+}
+
+static void vfio_generic_window_quirk_write(void *opaque, hwaddr addr,
+                                            uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+
+    if (ranges_overlap(addr, size,
+                       quirk->data.address_offset, quirk->data.address_size)) {
+
+        if (addr != quirk->data.address_offset) {
+            hw_error("%s: offset write into address window: %s",
+                     __func__, memory_region_name(&quirk->mem));
+        }
+
+        if ((data & ~quirk->data.address_mask) == quirk->data.address_match) {
+            quirk->data.flags |= quirk->data.write_flags |
+                                 quirk->data.read_flags;
+            quirk->data.address_val = data & quirk->data.address_mask;
+        } else {
+            quirk->data.flags &= ~(quirk->data.write_flags |
+                                   quirk->data.read_flags);
+        }
+    }
+
+    if (vfio_flags_enabled(quirk->data.flags, quirk->data.write_flags) &&
+        ranges_overlap(addr, size,
+                       quirk->data.data_offset, quirk->data.data_size)) {
+        hwaddr offset = addr - quirk->data.data_offset;
+
+        if (!vfio_range_contained(addr, size, quirk->data.data_offset,
+                                  quirk->data.data_size)) {
+            hw_error("%s: window data write not fully contained: %s",
+                     __func__, memory_region_name(&quirk->mem));
+        }
+
+        vfio_pci_write_config(&vdev->pdev,
+                              quirk->data.address_val + offset, data, size);
+        trace_vfio_generic_window_quirk_write(memory_region_name(&quirk->mem),
+                                              vdev->vbasedev.name,
+                                              quirk->data.bar,
+                                              addr, data, size);
+        return;
+    }
+
+    vfio_region_write(&vdev->bars[quirk->data.bar].region,
+                   addr + quirk->data.base_offset, data, size);
+}
+
+static const MemoryRegionOps vfio_generic_window_quirk = {
+    .read = vfio_generic_window_quirk_read,
+    .write = vfio_generic_window_quirk_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static uint64_t vfio_generic_quirk_read(void *opaque,
+                                        hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    hwaddr base = quirk->data.address_match & TARGET_PAGE_MASK;
+    hwaddr offset = quirk->data.address_match & ~TARGET_PAGE_MASK;
+    uint64_t data;
+
+    if (vfio_flags_enabled(quirk->data.flags, quirk->data.read_flags) &&
+        ranges_overlap(addr, size, offset, quirk->data.address_mask + 1)) {
+        if (!vfio_range_contained(addr, size, offset,
+                                  quirk->data.address_mask + 1)) {
+            hw_error("%s: read not fully contained: %s",
+                     __func__, memory_region_name(&quirk->mem));
+        }
+
+        data = vfio_pci_read_config(&vdev->pdev, addr - offset, size);
+
+        trace_vfio_generic_quirk_read(memory_region_name(&quirk->mem),
+                                      vdev->vbasedev.name, quirk->data.bar,
+                                      addr + base, size, data);
+    } else {
+        data = vfio_region_read(&vdev->bars[quirk->data.bar].region,
+                                addr + base, size);
+    }
+
+    return data;
+}
+
+static void vfio_generic_quirk_write(void *opaque, hwaddr addr,
+                                     uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    hwaddr base = quirk->data.address_match & TARGET_PAGE_MASK;
+    hwaddr offset = quirk->data.address_match & ~TARGET_PAGE_MASK;
+
+    if (vfio_flags_enabled(quirk->data.flags, quirk->data.write_flags) &&
+        ranges_overlap(addr, size, offset, quirk->data.address_mask + 1)) {
+        if (!vfio_range_contained(addr, size, offset,
+                                  quirk->data.address_mask + 1)) {
+            hw_error("%s: write not fully contained: %s",
+                     __func__, memory_region_name(&quirk->mem));
+        }
+
+        vfio_pci_write_config(&vdev->pdev, addr - offset, data, size);
+
+        trace_vfio_generic_quirk_write(memory_region_name(&quirk->mem),
+                                       vdev->vbasedev.name, quirk->data.bar,
+                                       addr + base, data, size);
+    } else {
+        vfio_region_write(&vdev->bars[quirk->data.bar].region,
+                          addr + base, data, size);
+    }
+}
+
+static const MemoryRegionOps vfio_generic_quirk = {
+    .read = vfio_generic_quirk_read,
+    .write = vfio_generic_quirk_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+#define PCI_VENDOR_ID_ATI               0x1002
+
+/*
+ * Radeon HD cards (HD5450 & HD7850) report the upper byte of the I/O port BAR
+ * through VGA register 0x3c3.  On newer cards, the I/O port BAR is always
+ * BAR4 (older cards like the X550 used BAR1, but we don't care to support
+ * those).  Note that on bare metal, a read of 0x3c3 doesn't always return the
+ * I/O port BAR address.  Originally this was coded to return the virtual BAR
+ * address only if the physical register read returns the actual BAR address,
+ * but users have reported greater success if we return the virtual address
+ * unconditionally.
+ */
+static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
+                                        hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    uint64_t data = vfio_pci_read_config(&vdev->pdev,
+                                         PCI_BASE_ADDRESS_0 + (4 * 4) + 1,
+                                         size);
+    trace_vfio_ati_3c3_quirk_read(data);
+
+    return data;
+}
+
+static const MemoryRegionOps vfio_ati_3c3_quirk = {
+    .read = vfio_ati_3c3_quirk_read,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void vfio_vga_probe_ati_3c3_quirk(VFIOPCIDevice *vdev)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_ATI) {
+        return;
+    }
+
+    /*
+     * As long as the BAR is >= 256 bytes it will be aligned such that the
+     * lower byte is always zero.  Filter out anything else, if it exists.
+     */
+    if (!vdev->bars[4].ioport || vdev->bars[4].region.size < 256) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_ati_3c3_quirk, quirk,
+                          "vfio-ati-3c3-quirk", 1);
+    memory_region_add_subregion(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem,
+                                3 /* offset 3 bytes from 0x3c0 */, &quirk->mem);
+
+    QLIST_INSERT_HEAD(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].quirks,
+                      quirk, next);
+
+    trace_vfio_vga_probe_ati_3c3_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * Newer ATI/AMD devices, including HD5450 and HD7850, have a window to PCI
+ * config space through MMIO BAR2 at offset 0x4000.  Nothing seems to access
+ * the MMIO space directly, but a window to this space is provided through
+ * I/O port BAR4.  Offset 0x0 is the address register and offset 0x4 is the
+ * data register.  When the address is programmed to a range of 0x4000-0x4fff
+ * PCI configuration space is available.  Experimentation seems to indicate
+ * that only read-only access is provided, but we drop writes when the window
+ * is enabled to config space nonetheless.
+ */
+static void vfio_probe_ati_bar4_window_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (!vdev->has_vga || nr != 4 ||
+        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_ATI) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.address_size = 4;
+    quirk->data.data_offset = 4;
+    quirk->data.data_size = 4;
+    quirk->data.address_match = 0x4000;
+    quirk->data.address_mask = PCIE_CONFIG_SPACE_SIZE - 1;
+    quirk->data.bar = nr;
+    quirk->data.read_flags = quirk->data.write_flags = 1;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev),
+                          &vfio_generic_window_quirk, quirk,
+                          "vfio-ati-bar4-window-quirk", 8);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                          quirk->data.base_offset, &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_probe_ati_bar4_window_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * Trap the BAR2 MMIO window to config space as well.
+ */
+static void vfio_probe_ati_bar2_4000_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    /* Only enable on newer devices where BAR2 is 64bit */
+    if (!vdev->has_vga || nr != 2 || !vdev->bars[2].mem64 ||
+        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_ATI) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.flags = quirk->data.read_flags = quirk->data.write_flags = 1;
+    quirk->data.address_match = 0x4000;
+    quirk->data.address_mask = PCIE_CONFIG_SPACE_SIZE - 1;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_generic_quirk, quirk,
+                          "vfio-ati-bar2-4000-quirk",
+                          TARGET_PAGE_ALIGN(quirk->data.address_mask + 1));
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                          quirk->data.address_match & TARGET_PAGE_MASK,
+                          &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_probe_ati_bar2_4000_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * Older ATI/AMD cards like the X550 have a similar window to that above.
+ * I/O port BAR1 provides a window to a mirror of PCI config space located
+ * in BAR2 at offset 0xf00.  We don't care to support such older cards, but
+ * note it for future reference.
+ */
+
+#define PCI_VENDOR_ID_NVIDIA                    0x10de
+
+/*
+ * Nvidia has several different methods to get to config space, the
+ * nouveu project has several of these documented here:
+ * https://github.com/pathscale/envytools/tree/master/hwdocs
+ *
+ * The first quirk is actually not documented in envytools and is found
+ * on 10de:01d1 (NVIDIA Corporation G72 [GeForce 7300 LE]).  This is an
+ * NV46 chipset.  The backdoor uses the legacy VGA I/O ports to access
+ * the mirror of PCI config space found at BAR0 offset 0x1800.  The access
+ * sequence first writes 0x338 to I/O port 0x3d4.  The target offset is
+ * then written to 0x3d0.  Finally 0x538 is written for a read and 0x738
+ * is written for a write to 0x3d4.  The BAR0 offset is then accessible
+ * through 0x3d0.  This quirk doesn't seem to be necessary on newer cards
+ * that use the I/O port BAR5 window but it doesn't hurt to leave it.
+ */
+enum {
+    NV_3D0_NONE = 0,
+    NV_3D0_SELECT,
+    NV_3D0_WINDOW,
+    NV_3D0_READ,
+    NV_3D0_WRITE,
+};
+
+static uint64_t vfio_nvidia_3d0_quirk_read(void *opaque,
+                                           hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    PCIDevice *pdev = &vdev->pdev;
+    uint64_t data = vfio_vga_read(&vdev->vga.region[QEMU_PCI_VGA_IO_HI],
+                                  addr + quirk->data.base_offset, size);
+
+    if (quirk->data.flags == NV_3D0_READ && addr == quirk->data.data_offset) {
+        data = vfio_pci_read_config(pdev, quirk->data.address_val, size);
+        trace_vfio_nvidia_3d0_quirk_read(size, data);
+    }
+
+    quirk->data.flags = NV_3D0_NONE;
+
+    return data;
+}
+
+static void vfio_nvidia_3d0_quirk_write(void *opaque, hwaddr addr,
+                                        uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    PCIDevice *pdev = &vdev->pdev;
+
+    switch (quirk->data.flags) {
+    case NV_3D0_NONE:
+        if (addr == quirk->data.address_offset && data == 0x338) {
+            quirk->data.flags = NV_3D0_SELECT;
+        }
+        break;
+    case NV_3D0_SELECT:
+        quirk->data.flags = NV_3D0_NONE;
+        if (addr == quirk->data.data_offset &&
+            (data & ~quirk->data.address_mask) == quirk->data.address_match) {
+            quirk->data.flags = NV_3D0_WINDOW;
+            quirk->data.address_val = data & quirk->data.address_mask;
+        }
+        break;
+    case NV_3D0_WINDOW:
+        quirk->data.flags = NV_3D0_NONE;
+        if (addr == quirk->data.address_offset) {
+            if (data == 0x538) {
+                quirk->data.flags = NV_3D0_READ;
+            } else if (data == 0x738) {
+                quirk->data.flags = NV_3D0_WRITE;
+            }
+        }
+        break;
+    case NV_3D0_WRITE:
+        quirk->data.flags = NV_3D0_NONE;
+        if (addr == quirk->data.data_offset) {
+            vfio_pci_write_config(pdev, quirk->data.address_val, data, size);
+            trace_vfio_nvidia_3d0_quirk_write(data, size);
+            return;
+        }
+        break;
+    }
+
+    vfio_vga_write(&vdev->vga.region[QEMU_PCI_VGA_IO_HI],
+                   addr + quirk->data.base_offset, data, size);
+}
+
+static const MemoryRegionOps vfio_nvidia_3d0_quirk = {
+    .read = vfio_nvidia_3d0_quirk_read,
+    .write = vfio_nvidia_3d0_quirk_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void vfio_vga_probe_nvidia_3d0_quirk(VFIOPCIDevice *vdev)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_NVIDIA ||
+        !vdev->bars[1].region.size) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.base_offset = 0x10;
+    quirk->data.address_offset = 4;
+    quirk->data.address_size = 2;
+    quirk->data.address_match = 0x1800;
+    quirk->data.address_mask = PCI_CONFIG_SPACE_SIZE - 1;
+    quirk->data.data_offset = 0;
+    quirk->data.data_size = 4;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_nvidia_3d0_quirk,
+                          quirk, "vfio-nvidia-3d0-quirk", 6);
+    memory_region_add_subregion(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].mem,
+                                quirk->data.base_offset, &quirk->mem);
+
+    QLIST_INSERT_HEAD(&vdev->vga.region[QEMU_PCI_VGA_IO_HI].quirks,
+                      quirk, next);
+
+    trace_vfio_vga_probe_nvidia_3d0_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * The second quirk is documented in envytools.  The I/O port BAR5 is just
+ * a set of address/data ports to the MMIO BARs.  The BAR we care about is
+ * again BAR0.  This backdoor is apparently a bit newer than the one above
+ * so we need to not only trap 256 bytes @0x1800, but all of PCI config
+ * space, including extended space is available at the 4k @0x88000.
+ */
+enum {
+    NV_BAR5_ADDRESS = 0x1,
+    NV_BAR5_ENABLE = 0x2,
+    NV_BAR5_MASTER = 0x4,
+    NV_BAR5_VALID = 0x7,
+};
+
+static void vfio_nvidia_bar5_window_quirk_write(void *opaque, hwaddr addr,
+                                                uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+
+    switch (addr) {
+    case 0x0:
+        if (data & 0x1) {
+            quirk->data.flags |= NV_BAR5_MASTER;
+        } else {
+            quirk->data.flags &= ~NV_BAR5_MASTER;
+        }
+        break;
+    case 0x4:
+        if (data & 0x1) {
+            quirk->data.flags |= NV_BAR5_ENABLE;
+        } else {
+            quirk->data.flags &= ~NV_BAR5_ENABLE;
+        }
+        break;
+    case 0x8:
+        if (quirk->data.flags & NV_BAR5_MASTER) {
+            if ((data & ~0xfff) == 0x88000) {
+                quirk->data.flags |= NV_BAR5_ADDRESS;
+                quirk->data.address_val = data & 0xfff;
+            } else if ((data & ~0xff) == 0x1800) {
+                quirk->data.flags |= NV_BAR5_ADDRESS;
+                quirk->data.address_val = data & 0xff;
+            } else {
+                quirk->data.flags &= ~NV_BAR5_ADDRESS;
+            }
+        }
+        break;
+    }
+
+    vfio_generic_window_quirk_write(opaque, addr, data, size);
+}
+
+static const MemoryRegionOps vfio_nvidia_bar5_window_quirk = {
+    .read = vfio_generic_window_quirk_read,
+    .write = vfio_nvidia_bar5_window_quirk_write,
+    .valid.min_access_size = 4,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void vfio_probe_nvidia_bar5_window_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (!vdev->has_vga || nr != 5 ||
+        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_NVIDIA) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.read_flags = quirk->data.write_flags = NV_BAR5_VALID;
+    quirk->data.address_offset = 0x8;
+    quirk->data.address_size = 0; /* actually 4, but avoids generic code */
+    quirk->data.data_offset = 0xc;
+    quirk->data.data_size = 4;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev),
+                          &vfio_nvidia_bar5_window_quirk, quirk,
+                          "vfio-nvidia-bar5-window-quirk", 16);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        0, &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_probe_nvidia_bar5_window_quirk(vdev->vbasedev.name);
+}
+
+static void vfio_nvidia_88000_quirk_write(void *opaque, hwaddr addr,
+                                          uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    PCIDevice *pdev = &vdev->pdev;
+    hwaddr base = quirk->data.address_match & TARGET_PAGE_MASK;
+
+    vfio_generic_quirk_write(opaque, addr, data, size);
+
+    /*
+     * Nvidia seems to acknowledge MSI interrupts by writing 0xff to the
+     * MSI capability ID register.  Both the ID and next register are
+     * read-only, so we allow writes covering either of those to real hw.
+     * NB - only fixed for the 0x88000 MMIO window.
+     */
+    if ((pdev->cap_present & QEMU_PCI_CAP_MSI) &&
+        vfio_range_contained(addr, size, pdev->msi_cap, PCI_MSI_FLAGS)) {
+        vfio_region_write(&vdev->bars[quirk->data.bar].region,
+                          addr + base, data, size);
+    }
+}
+
+static const MemoryRegionOps vfio_nvidia_88000_quirk = {
+    .read = vfio_generic_quirk_read,
+    .write = vfio_nvidia_88000_quirk_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+/*
+ * Finally, BAR0 itself.  We want to redirect any accesses to either
+ * 0x1800 or 0x88000 through the PCI config space access functions.
+ *
+ * NB - quirk at a page granularity or else they don't seem to work when
+ *      BARs are mmap'd
+ *
+ * Here's offset 0x88000...
+ */
+static void vfio_probe_nvidia_bar0_88000_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+    uint16_t vendor, class;
+
+    vendor = pci_get_word(pdev->config + PCI_VENDOR_ID);
+    class = pci_get_word(pdev->config + PCI_CLASS_DEVICE);
+
+    if (nr != 0 || vendor != PCI_VENDOR_ID_NVIDIA ||
+        class != PCI_CLASS_DISPLAY_VGA) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.flags = quirk->data.read_flags = quirk->data.write_flags = 1;
+    quirk->data.address_match = 0x88000;
+    quirk->data.address_mask = PCIE_CONFIG_SPACE_SIZE - 1;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_nvidia_88000_quirk,
+                          quirk, "vfio-nvidia-bar0-88000-quirk",
+                          TARGET_PAGE_ALIGN(quirk->data.address_mask + 1));
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                          quirk->data.address_match & TARGET_PAGE_MASK,
+                          &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_probe_nvidia_bar0_88000_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * And here's the same for BAR0 offset 0x1800...
+ */
+static void vfio_probe_nvidia_bar0_1800_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (!vdev->has_vga || nr != 0 ||
+        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_NVIDIA) {
+        return;
+    }
+
+    /* Log the chipset ID */
+    trace_vfio_probe_nvidia_bar0_1800_quirk_id(
+            (unsigned int)(vfio_region_read(&vdev->bars[0].region, 0, 4) >> 20)
+            & 0xff);
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.flags = quirk->data.read_flags = quirk->data.write_flags = 1;
+    quirk->data.address_match = 0x1800;
+    quirk->data.address_mask = PCI_CONFIG_SPACE_SIZE - 1;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_generic_quirk, quirk,
+                          "vfio-nvidia-bar0-1800-quirk",
+                          TARGET_PAGE_ALIGN(quirk->data.address_mask + 1));
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                          quirk->data.address_match & TARGET_PAGE_MASK,
+                          &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_probe_nvidia_bar0_1800_quirk(vdev->vbasedev.name);
+}
+
+/*
+ * TODO - Some Nvidia devices provide config access to their companion HDA
+ * device and even to their parent bridge via these config space mirrors.
+ * Add quirks for those regions.
+ */
+
+#define PCI_VENDOR_ID_REALTEK 0x10ec
+
+/*
+ * RTL8168 devices have a backdoor that can access the MSI-X table.  At BAR2
+ * offset 0x70 there is a dword data register, offset 0x74 is a dword address
+ * register.  According to the Linux r8169 driver, the MSI-X table is addressed
+ * when the "type" portion of the address register is set to 0x1.  This appears
+ * to be bits 16:30.  Bit 31 is both a write indicator and some sort of
+ * "address latched" indicator.  Bits 12:15 are a mask field, which we can
+ * ignore because the MSI-X table should always be accessed as a dword (full
+ * mask).  Bits 0:11 is offset within the type.
+ *
+ * Example trace:
+ *
+ * Read from MSI-X table offset 0
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x74, 0x1f000, 4) // store read addr
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x74, 4) = 0x8001f000 // latch
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x70, 4) = 0xfee00398 // read data
+ *
+ * Write 0xfee00000 to MSI-X table offset 0
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x70, 0xfee00000, 4) // write data
+ * vfio: vfio_bar_write(0000:05:00.0:BAR2+0x74, 0x8001f000, 4) // do write
+ * vfio: vfio_bar_read(0000:05:00.0:BAR2+0x74, 4) = 0x1f000 // complete
+ */
+static uint64_t vfio_rtl8168_window_quirk_read(void *opaque,
+                                               hwaddr addr, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+    uint64_t val = 0;
+
+    if (!quirk->data.flags) { /* Non-MSI-X table access */
+        return vfio_region_read(&vdev->bars[quirk->data.bar].region,
+                                addr + 0x70, size);
+    }
+
+    switch (addr) {
+    case 4: /* address */
+        val = quirk->data.address_match ^ 0x80000000U; /* latch/complete */
+        break;
+    case 0: /* data */
+        if ((vdev->pdev.cap_present & QEMU_PCI_CAP_MSIX)) {
+            memory_region_dispatch_read(&vdev->pdev.msix_table_mmio,
+                                (hwaddr)(quirk->data.address_match & 0xfff),
+                                &val, size, MEMTXATTRS_UNSPECIFIED);
+        }
+        break;
+    }
+
+    trace_vfio_rtl8168_quirk_read(vdev->vbasedev.name,
+                                  addr ? "address" : "data", val);
+    return val;
+}
+
+static void vfio_rtl8168_window_quirk_write(void *opaque, hwaddr addr,
+                                            uint64_t data, unsigned size)
+{
+    VFIOQuirk *quirk = opaque;
+    VFIOPCIDevice *vdev = quirk->vdev;
+
+    switch (addr) {
+    case 4: /* address */
+        if ((data & 0x7fff0000) == 0x10000) { /* MSI-X table */
+            quirk->data.flags = 1; /* Activate reads */
+            quirk->data.address_match = data;
+
+            trace_vfio_rtl8168_quirk_write(vdev->vbasedev.name, data);
+
+            if (data & 0x80000000U) { /* Do write */
+                if (vdev->pdev.cap_present & QEMU_PCI_CAP_MSIX) {
+                    hwaddr offset = data & 0xfff;
+                    uint64_t val = quirk->data.address_mask;
+
+                    trace_vfio_rtl8168_quirk_msix(vdev->vbasedev.name,
+                                                  (uint16_t)offset, val);
+
+                    /* Write to the proper guest MSI-X table instead */
+                    memory_region_dispatch_write(&vdev->pdev.msix_table_mmio,
+                                                 offset, val, size,
+                                                 MEMTXATTRS_UNSPECIFIED);
+                }
+                return; /* Do not write guest MSI-X data to hardware */
+            }
+        } else {
+            quirk->data.flags = 0; /* De-activate reads, non-MSI-X */
+        }
+        break;
+    case 0: /* data */
+        quirk->data.address_mask = data;
+        break;
+    }
+
+    vfio_region_write(&vdev->bars[quirk->data.bar].region,
+                      addr + 0x70, data, size);
+}
+
+static const MemoryRegionOps vfio_rtl8168_window_quirk = {
+    .read = vfio_rtl8168_window_quirk_read,
+    .write = vfio_rtl8168_window_quirk_write,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+        .unaligned = false,
+    },
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void vfio_probe_rtl8168_bar2_window_quirk(VFIOPCIDevice *vdev, int nr)
+{
+    PCIDevice *pdev = &vdev->pdev;
+    VFIOQuirk *quirk;
+
+    if (pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_REALTEK ||
+        pci_get_word(pdev->config + PCI_DEVICE_ID) != 0x8168 || nr != 2) {
+        return;
+    }
+
+    quirk = g_malloc0(sizeof(*quirk));
+    quirk->vdev = vdev;
+    quirk->data.bar = nr;
+
+    memory_region_init_io(&quirk->mem, OBJECT(vdev), &vfio_rtl8168_window_quirk,
+                          quirk, "vfio-rtl8168-window-quirk", 8);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        0x70, &quirk->mem, 1);
+
+    QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
+
+    trace_vfio_rtl8168_quirk_enable(vdev->vbasedev.name);
+}
+
+/*
+ * Common quirk probe entry points.
+ */
+void vfio_vga_quirk_setup(VFIOPCIDevice *vdev)
+{
+    vfio_vga_probe_ati_3c3_quirk(vdev);
+    vfio_vga_probe_nvidia_3d0_quirk(vdev);
+}
+
+void vfio_vga_quirk_teardown(VFIOPCIDevice *vdev)
+{
+    VFIOQuirk *quirk;
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(vdev->vga.region); i++) {
+        QLIST_FOREACH(quirk, &vdev->vga.region[i].quirks, next) {
+            memory_region_del_subregion(&vdev->vga.region[i].mem, &quirk->mem);
+        }
+    }
+}
+
+void vfio_vga_quirk_free(VFIOPCIDevice *vdev)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(vdev->vga.region); i++) {
+        while (!QLIST_EMPTY(&vdev->vga.region[i].quirks)) {
+            VFIOQuirk *quirk = QLIST_FIRST(&vdev->vga.region[i].quirks);
+            object_unparent(OBJECT(&quirk->mem));
+            QLIST_REMOVE(quirk, next);
+            g_free(quirk);
+        }
+    }
+}
+
+void vfio_bar_quirk_setup(VFIOPCIDevice *vdev, int nr)
+{
+    vfio_probe_ati_bar4_window_quirk(vdev, nr);
+    vfio_probe_ati_bar2_4000_quirk(vdev, nr);
+    vfio_probe_nvidia_bar5_window_quirk(vdev, nr);
+    vfio_probe_nvidia_bar0_88000_quirk(vdev, nr);
+    vfio_probe_nvidia_bar0_1800_quirk(vdev, nr);
+    vfio_probe_rtl8168_bar2_window_quirk(vdev, nr);
+}
+
+void vfio_bar_quirk_teardown(VFIOPCIDevice *vdev, int nr)
+{
+    VFIOBAR *bar = &vdev->bars[nr];
+    VFIOQuirk *quirk;
+
+    QLIST_FOREACH(quirk, &bar->quirks, next) {
+        memory_region_del_subregion(&bar->region.mem, &quirk->mem);
+    }
+}
+
+void vfio_bar_quirk_free(VFIOPCIDevice *vdev, int nr)
+{
+    VFIOBAR *bar = &vdev->bars[nr];
+
+    while (!QLIST_EMPTY(&bar->quirks)) {
+        VFIOQuirk *quirk = QLIST_FIRST(&bar->quirks);
+        object_unparent(OBJECT(&quirk->mem));
+        QLIST_REMOVE(quirk, next);
+        g_free(quirk);
+    }
+}