vfio/pci: Config window quirks

Config windows make use of an address register and a data register.
In VGA cards, these are often used to provide real mode code in the
BIOS an easy way to access MMIO registers since the window often
resides in an I/O port register.  When the MMIO register has a mirror
of PCI config space, we need to trap those accesses and redirect them
to emulated config space.

The previous version of this functionality made use of a single
MemoryRegion and single match address.  This version uses separate
MemoryRegions for each of the address and data registers and allows
for multiple match addresses.  This is useful for Nvidia cards which
have two ranges which index into PCI config space.

The previous implementation is left for the follow-on patch for a more
reviewable diff.

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

1 files changed, 270 insertions, 88 deletions

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index b3bb2f8..89e8121 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -63,9 +63,127 @@ bool vfio_blacklist_opt_rom(VFIOPCIDevice *vdev)
 }
 
 /*
- * Device specific quirks
+ * Device specific region quirks (mostly backdoors to PCI config space)
  */
 
+/*
+ * The generic window quirks operate on an address and data register,
+ * vfio_generic_window_address_quirk handles the address register and
+ * vfio_generic_window_data_quirk handles the data register.  These ops
+ * pass reads and writes through to hardware until a value matching the
+ * stored address match/mask is written.  When this occurs, the data
+ * register access emulated PCI config space for the device rather than
+ * passing through accesses.  This enables devices where PCI config space
+ * is accessible behind a window register to maintain the virtualization
+ * provided through vfio.
+ */
+typedef struct VFIOConfigWindowMatch {
+    uint32_t match;
+    uint32_t mask;
+} VFIOConfigWindowMatch;
+
+typedef struct VFIOConfigWindowQuirk {
+    struct VFIOPCIDevice *vdev;
+
+    uint32_t address_val;
+
+    uint32_t address_offset;
+    uint32_t data_offset;
+
+    bool window_enabled;
+    uint8_t bar;
+
+    MemoryRegion *addr_mem;
+    MemoryRegion *data_mem;
+
+    uint32_t nr_matches;
+    VFIOConfigWindowMatch matches[];
+} VFIOConfigWindowQuirk;
+
+static uint64_t vfio_generic_window_quirk_address_read(void *opaque,
+                                                       hwaddr addr,
+                                                       unsigned size)
+{
+    VFIOConfigWindowQuirk *window = opaque;
+    VFIOPCIDevice *vdev = window->vdev;
+
+    return vfio_region_read(&vdev->bars[window->bar].region,
+                            addr + window->address_offset, size);
+}
+
+static void vfio_generic_window_quirk_address_write(void *opaque, hwaddr addr,
+                                                    uint64_t data,
+                                                    unsigned size)
+{
+    VFIOConfigWindowQuirk *window = opaque;
+    VFIOPCIDevice *vdev = window->vdev;
+    int i;
+
+    window->window_enabled = false;
+
+    vfio_region_write(&vdev->bars[window->bar].region,
+                      addr + window->address_offset, data, size);
+
+    for (i = 0; i < window->nr_matches; i++) {
+        if ((data & ~window->matches[i].mask) == window->matches[i].match) {
+            window->window_enabled = true;
+            window->address_val = data & window->matches[i].mask;
+            trace_vfio_quirk_generic_window_address_write(vdev->vbasedev.name,
+                                    memory_region_name(window->addr_mem), data);
+            break;
+        }
+    }
+}
+
+static const MemoryRegionOps vfio_generic_window_address_quirk = {
+    .read = vfio_generic_window_quirk_address_read,
+    .write = vfio_generic_window_quirk_address_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static uint64_t vfio_generic_window_quirk_data_read(void *opaque,
+                                                    hwaddr addr, unsigned size)
+{
+    VFIOConfigWindowQuirk *window = opaque;
+    VFIOPCIDevice *vdev = window->vdev;
+    uint64_t data;
+
+    /* Always read data reg, discard if window enabled */
+    data = vfio_region_read(&vdev->bars[window->bar].region,
+                            addr + window->data_offset, size);
+
+    if (window->window_enabled) {
+        data = vfio_pci_read_config(&vdev->pdev, window->address_val, size);
+        trace_vfio_quirk_generic_window_data_read(vdev->vbasedev.name,
+                                    memory_region_name(window->data_mem), data);
+    }
+
+    return data;
+}
+
+static void vfio_generic_window_quirk_data_write(void *opaque, hwaddr addr,
+                                                 uint64_t data, unsigned size)
+{
+    VFIOConfigWindowQuirk *window = opaque;
+    VFIOPCIDevice *vdev = window->vdev;
+
+    if (window->window_enabled) {
+        vfio_pci_write_config(&vdev->pdev, window->address_val, data, size);
+        trace_vfio_quirk_generic_window_data_write(vdev->vbasedev.name,
+                                    memory_region_name(window->data_mem), data);
+        return;
+    }
+
+    vfio_region_write(&vdev->bars[window->bar].region,
+                      addr + window->data_offset, data, size);
+}
+
+static const MemoryRegionOps vfio_generic_window_data_quirk = {
+    .read = vfio_generic_window_quirk_data_read,
+    .write = vfio_generic_window_quirk_data_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
 /* Is range1 fully contained within range2?  */
 static bool vfio_range_contained(uint64_t first1, uint64_t len1,
                                  uint64_t first2, uint64_t len2) {
@@ -285,48 +403,57 @@ static void vfio_vga_probe_ati_3c3_quirk(VFIOPCIDevice *vdev)
 }
 
 /*
- * Newer ATI/AMD devices, including HD5450 and HD7850, have a window to PCI
+ * Newer ATI/AMD devices, including HD5450 and HD7850, have a mirror 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.
+ * that read-only may be provided by hardware.
  */
-static void vfio_probe_ati_bar4_window_quirk(VFIOPCIDevice *vdev, int nr)
+static void vfio_probe_ati_bar4_quirk(VFIOPCIDevice *vdev, int nr)
 {
-    PCIDevice *pdev = &vdev->pdev;
     VFIOQuirk *quirk;
-    VFIOLegacyQuirk *legacy;
+    VFIOConfigWindowQuirk *window;
 
-    if (!vdev->has_vga || nr != 4 ||
-        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_ATI) {
+    /* This windows doesn't seem to be used except by legacy VGA code */
+    if (!vfio_pci_is(vdev, PCI_VENDOR_ID_ATI, PCI_ANY_ID) ||
+        !vdev->has_vga || nr != 4) {
         return;
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->data = legacy = g_malloc0(sizeof(*legacy));
-    quirk->mem = legacy->mem = g_malloc0_n(sizeof(MemoryRegion), 1);
-    quirk->nr_mem = 1;
-    legacy->vdev = vdev;
-    legacy->data.address_size = 4;
-    legacy->data.data_offset = 4;
-    legacy->data.data_size = 4;
-    legacy->data.address_match = 0x4000;
-    legacy->data.address_mask = PCIE_CONFIG_SPACE_SIZE - 1;
-    legacy->data.bar = nr;
-    legacy->data.read_flags = legacy->data.write_flags = 1;
+    quirk->mem = g_malloc0_n(sizeof(MemoryRegion), 2);
+    quirk->nr_mem = 2;
+    window = quirk->data = g_malloc0(sizeof(*window) +
+                                     sizeof(VFIOConfigWindowMatch));
+    window->vdev = vdev;
+    window->address_offset = 0;
+    window->data_offset = 4;
+    window->nr_matches = 1;
+    window->matches[0].match = 0x4000;
+    window->matches[0].mask = PCIE_CONFIG_SPACE_SIZE - 1;
+    window->bar = nr;
+    window->addr_mem = &quirk->mem[0];
+    window->data_mem = &quirk->mem[1];
+
+    memory_region_init_io(window->addr_mem, OBJECT(vdev),
+                          &vfio_generic_window_address_quirk, window,
+                          "vfio-ati-bar4-window-address-quirk", 4);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        window->address_offset,
+                                        window->addr_mem, 1);
 
-    memory_region_init_io(quirk->mem, OBJECT(vdev),
-                          &vfio_generic_window_quirk, legacy,
-                          "vfio-ati-bar4-window-quirk", 8);
+    memory_region_init_io(window->data_mem, OBJECT(vdev),
+                          &vfio_generic_window_data_quirk, window,
+                          "vfio-ati-bar4-window-data-quirk", 4);
     memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
-                          legacy->data.base_offset, quirk->mem, 1);
+                                        window->data_offset,
+                                        window->data_mem, 1);
 
     QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
 
-    trace_vfio_probe_ati_bar4_window_quirk(vdev->vbasedev.name);
+    trace_vfio_quirk_ati_bar4_probe(vdev->vbasedev.name);
 }
 
 /*
@@ -552,90 +679,145 @@ static void vfio_vga_probe_nvidia_3d0_quirk(VFIOPCIDevice *vdev)
  * 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,
+typedef struct VFIONvidiaBAR5Quirk {
+    uint32_t master;
+    uint32_t enable;
+    MemoryRegion *addr_mem;
+    MemoryRegion *data_mem;
+    bool enabled;
+    VFIOConfigWindowQuirk window; /* last for match data */
+} VFIONvidiaBAR5Quirk;
+
+static void vfio_nvidia_bar5_enable(VFIONvidiaBAR5Quirk *bar5)
+{
+    VFIOPCIDevice *vdev = bar5->window.vdev;
+
+    if (((bar5->master & bar5->enable) & 0x1) == bar5->enabled) {
+        return;
+    }
+
+    bar5->enabled = !bar5->enabled;
+    trace_vfio_quirk_nvidia_bar5_state(vdev->vbasedev.name,
+                                       bar5->enabled ?  "Enable" : "Disable");
+    memory_region_set_enabled(bar5->addr_mem, bar5->enabled);
+    memory_region_set_enabled(bar5->data_mem, bar5->enabled);
+}
+
+static uint64_t vfio_nvidia_bar5_quirk_master_read(void *opaque,
+                                                   hwaddr addr, unsigned size)
+{
+    VFIONvidiaBAR5Quirk *bar5 = opaque;
+    VFIOPCIDevice *vdev = bar5->window.vdev;
+
+    return vfio_region_read(&vdev->bars[5].region, addr, size);
+}
+
+static void vfio_nvidia_bar5_quirk_master_write(void *opaque, hwaddr addr,
+                                                uint64_t data, unsigned size)
+{
+    VFIONvidiaBAR5Quirk *bar5 = opaque;
+    VFIOPCIDevice *vdev = bar5->window.vdev;
+
+    vfio_region_write(&vdev->bars[5].region, addr, data, size);
+
+    bar5->master = data;
+    vfio_nvidia_bar5_enable(bar5);
+}
+
+static const MemoryRegionOps vfio_nvidia_bar5_quirk_master = {
+    .read = vfio_nvidia_bar5_quirk_master_read,
+    .write = vfio_nvidia_bar5_quirk_master_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
-static void vfio_nvidia_bar5_window_quirk_write(void *opaque, hwaddr addr,
+static uint64_t vfio_nvidia_bar5_quirk_enable_read(void *opaque,
+                                                   hwaddr addr, unsigned size)
+{
+    VFIONvidiaBAR5Quirk *bar5 = opaque;
+    VFIOPCIDevice *vdev = bar5->window.vdev;
+
+    return vfio_region_read(&vdev->bars[5].region, addr + 4, size);
+}
+
+static void vfio_nvidia_bar5_quirk_enable_write(void *opaque, hwaddr addr,
                                                 uint64_t data, unsigned size)
 {
-    VFIOLegacyQuirk *quirk = opaque;
+    VFIONvidiaBAR5Quirk *bar5 = opaque;
+    VFIOPCIDevice *vdev = bar5->window.vdev;
 
-    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_region_write(&vdev->bars[5].region, addr + 4, data, size);
 
-    vfio_generic_window_quirk_write(opaque, addr, data, size);
+    bar5->enable = data;
+    vfio_nvidia_bar5_enable(bar5);
 }
 
-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,
+static const MemoryRegionOps vfio_nvidia_bar5_quirk_enable = {
+    .read = vfio_nvidia_bar5_quirk_enable_read,
+    .write = vfio_nvidia_bar5_quirk_enable_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
-static void vfio_probe_nvidia_bar5_window_quirk(VFIOPCIDevice *vdev, int nr)
+static void vfio_probe_nvidia_bar5_quirk(VFIOPCIDevice *vdev, int nr)
 {
-    PCIDevice *pdev = &vdev->pdev;
     VFIOQuirk *quirk;
-    VFIOLegacyQuirk *legacy;
+    VFIONvidiaBAR5Quirk *bar5;
+    VFIOConfigWindowQuirk *window;
 
-    if (!vdev->has_vga || nr != 5 ||
-        pci_get_word(pdev->config + PCI_VENDOR_ID) != PCI_VENDOR_ID_NVIDIA) {
+    if (!vfio_pci_is(vdev, PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID) ||
+        !vdev->has_vga || nr != 5) {
         return;
     }
 
     quirk = g_malloc0(sizeof(*quirk));
-    quirk->data = legacy = g_malloc0(sizeof(*legacy));
-    quirk->mem = legacy->mem = g_malloc0_n(sizeof(MemoryRegion), 1);
-    quirk->nr_mem = 1;
-    legacy->vdev = vdev;
-    legacy->data.read_flags = legacy->data.write_flags = NV_BAR5_VALID;
-    legacy->data.address_offset = 0x8;
-    legacy->data.address_size = 0; /* actually 4, but avoids generic code */
-    legacy->data.data_offset = 0xc;
-    legacy->data.data_size = 4;
-    legacy->data.bar = nr;
+    quirk->mem = g_malloc0_n(sizeof(MemoryRegion), 4);
+    quirk->nr_mem = 4;
+    bar5 = quirk->data = g_malloc0(sizeof(*bar5) +
+                                   (sizeof(VFIOConfigWindowMatch) * 2));
+    window = &bar5->window;
+
+    window->vdev = vdev;
+    window->address_offset = 0x8;
+    window->data_offset = 0xc;
+    window->nr_matches = 2;
+    window->matches[0].match = 0x1800;
+    window->matches[0].mask = PCI_CONFIG_SPACE_SIZE - 1;
+    window->matches[1].match = 0x88000;
+    window->matches[1].mask = PCIE_CONFIG_SPACE_SIZE - 1;
+    window->bar = nr;
+    window->addr_mem = bar5->addr_mem = &quirk->mem[0];
+    window->data_mem = bar5->data_mem = &quirk->mem[1];
+
+    memory_region_init_io(window->addr_mem, OBJECT(vdev),
+                          &vfio_generic_window_address_quirk, window,
+                          "vfio-nvidia-bar5-window-address-quirk", 4);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        window->address_offset,
+                                        window->addr_mem, 1);
+    memory_region_set_enabled(window->addr_mem, false);
+
+    memory_region_init_io(window->data_mem, OBJECT(vdev),
+                          &vfio_generic_window_data_quirk, window,
+                          "vfio-nvidia-bar5-window-data-quirk", 4);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        window->data_offset,
+                                        window->data_mem, 1);
+    memory_region_set_enabled(window->data_mem, false);
+
+    memory_region_init_io(&quirk->mem[2], OBJECT(vdev),
+                          &vfio_nvidia_bar5_quirk_master, bar5,
+                          "vfio-nvidia-bar5-master-quirk", 4);
+    memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
+                                        0, &quirk->mem[2], 1);
 
-    memory_region_init_io(quirk->mem, OBJECT(vdev),
-                          &vfio_nvidia_bar5_window_quirk, legacy,
-                          "vfio-nvidia-bar5-window-quirk", 16);
+    memory_region_init_io(&quirk->mem[3], OBJECT(vdev),
+                          &vfio_nvidia_bar5_quirk_enable, bar5,
+                          "vfio-nvidia-bar5-enable-quirk", 4);
     memory_region_add_subregion_overlap(&vdev->bars[nr].region.mem,
-                                        0, quirk->mem, 1);
+                                        4, &quirk->mem[3], 1);
 
     QLIST_INSERT_HEAD(&vdev->bars[nr].quirks, quirk, next);
 
-    trace_vfio_probe_nvidia_bar5_window_quirk(vdev->vbasedev.name);
+    trace_vfio_quirk_nvidia_bar5_probe(vdev->vbasedev.name);
 }
 
 static void vfio_nvidia_88000_quirk_write(void *opaque, hwaddr addr,
@@ -964,9 +1146,9 @@ void vfio_vga_quirk_free(VFIOPCIDevice *vdev)
 
 void vfio_bar_quirk_setup(VFIOPCIDevice *vdev, int nr)
 {
-    vfio_probe_ati_bar4_window_quirk(vdev, nr);
+    vfio_probe_ati_bar4_quirk(vdev, nr);
     vfio_probe_ati_bar2_4000_quirk(vdev, nr);
-    vfio_probe_nvidia_bar5_window_quirk(vdev, nr);
+    vfio_probe_nvidia_bar5_quirk(vdev, nr);
     vfio_probe_nvidia_bar0_88000_quirk(vdev, nr);
     vfio_probe_nvidia_bar0_1800_quirk(vdev, nr);
     vfio_probe_rtl8168_bar2_quirk(vdev, nr);