[PATCH v5 01/17] hw/vfio/pci: Ensure MSI and MSI-X do not overlap

[Akihiko Odaki]

vfio_add_std_cap() is designed to ensure that capabilities do not
overlap, but it failed to do so for MSI and MSI-X capabilities.

Ensure MSI and MSI-X capabilities do not overlap with others by omitting
other overlapping capabilities.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/vfio/pci.c | 63 +++++++++++++++++++++++++++++++++++++++++++--------
 hw/vfio/pci.h |  3 +++
 2 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 939dcc3d4a..36c8f3dc85 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1278,23 +1278,42 @@ static void vfio_disable_interrupts(VFIOPCIDevice *vdev)
     }
 }
 
-static int vfio_msi_setup(VFIOPCIDevice *vdev, int pos, Error **errp)
+static void vfio_msi_early_setup(VFIOPCIDevice *vdev, Error **errp)
 {
     uint16_t ctrl;
-    bool msi_64bit, msi_maskbit;
-    int ret, entries;
-    Error *err = NULL;
+    uint8_t pos;
+
+    pos = pci_find_capability(&vdev->pdev, PCI_CAP_ID_MSI);
+    if (!pos) {
+        return;
+    }
 
     if (pread(vdev->vbasedev.fd, &ctrl, sizeof(ctrl),
               vdev->config_offset + pos + PCI_CAP_FLAGS) != sizeof(ctrl)) {
         error_setg_errno(errp, errno, "failed reading MSI PCI_CAP_FLAGS");
-        return -errno;
+        return;
     }
-    ctrl = le16_to_cpu(ctrl);
+    vdev->msi_pos = pos;
+    vdev->msi_ctrl = le16_to_cpu(ctrl);
 
-    msi_64bit = !!(ctrl & PCI_MSI_FLAGS_64BIT);
-    msi_maskbit = !!(ctrl & PCI_MSI_FLAGS_MASKBIT);
-    entries = 1 << ((ctrl & PCI_MSI_FLAGS_QMASK) >> 1);
+    vdev->msi_cap_size = 0xa;
+    if ((vdev->msi_ctrl & PCI_MSI_FLAGS_MASKBIT)) {
+        vdev->msi_cap_size += 0xa;
+    }
+    if ((vdev->msi_ctrl & PCI_MSI_FLAGS_64BIT)) {
+        vdev->msi_cap_size += 0x4;
+    }
+}
+
+static int vfio_msi_setup(VFIOPCIDevice *vdev, int pos, Error **errp)
+{
+    bool msi_64bit, msi_maskbit;
+    int ret, entries;
+    Error *err = NULL;
+
+    msi_64bit = !!(vdev->msi_ctrl & PCI_MSI_FLAGS_64BIT);
+    msi_maskbit = !!(vdev->msi_ctrl & PCI_MSI_FLAGS_MASKBIT);
+    entries = 1 << ((vdev->msi_ctrl & PCI_MSI_FLAGS_QMASK) >> 1);
 
     trace_vfio_msi_setup(vdev->vbasedev.name, pos);
 
@@ -1306,7 +1325,6 @@ static int vfio_msi_setup(VFIOPCIDevice *vdev, int pos, 
Error **errp)
         error_propagate_prepend(errp, err, "msi_init failed: ");
         return ret;
     }
-    vdev->msi_cap_size = 0xa + (msi_maskbit ? 0xa : 0) + (msi_64bit ? 0x4 : 0);
 
     return 0;
 }
@@ -1524,6 +1542,7 @@ static void vfio_msix_early_setup(VFIOPCIDevice *vdev, 
Error **errp)
     pba = le32_to_cpu(pba);
 
     msix = g_malloc0(sizeof(*msix));
+    msix->pos = pos;
     msix->table_bar = table & PCI_MSIX_FLAGS_BIRMASK;
     msix->table_offset = table & ~PCI_MSIX_FLAGS_BIRMASK;
     msix->pba_bar = pba & PCI_MSIX_FLAGS_BIRMASK;
@@ -2025,6 +2044,24 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t 
pos, Error **errp)
         }
     }
 
+    if (cap_id != PCI_CAP_ID_MSI &&
+        range_covers_byte(vdev->msi_pos, vdev->msi_cap_size, pos)) {
+        warn_report(VFIO_MSG_PREFIX
+                    "A capability overlaps with MSI, ignoring (%" PRIu8 " @ %" 
PRIu8 " in [%" PRIu8 ", %" PRIu8 "))",
+                    vdev->vbasedev.name, cap_id, pos,
+                    vdev->msi_pos, vdev->msi_pos + vdev->msi_cap_size);
+        return 0;
+    }
+
+    if (cap_id != PCI_CAP_ID_MSIX && vdev->msix &&
+        range_covers_byte(vdev->msix->pos, MSIX_CAP_LENGTH, pos)) {
+        warn_report(VFIO_MSG_PREFIX
+                    "A capability overlaps with MSI-X, ignoring (%" PRIu8 " @ 
%" PRIu8 " in [%" PRIu8 ", %" PRIu8 "))",
+                    vdev->vbasedev.name, cap_id, pos,
+                    vdev->msix->pos, vdev->msix->pos + MSIX_CAP_LENGTH);
+        return 0;
+    }
+
     /* Scale down size, esp in case virt caps were added above */
     size = MIN(size, vfio_std_cap_max_size(pdev, pos));
 
@@ -3037,6 +3074,12 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
 
     vfio_bars_prepare(vdev);
 
+    vfio_msi_early_setup(vdev, &err);
+    if (err) {
+        error_propagate(errp, err);
+        goto error;
+    }
+
     vfio_msix_early_setup(vdev, &err);
     if (err) {
         error_propagate(errp, err);
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index 7c236a52f4..9ae0278058 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -107,6 +107,7 @@ enum {
 
 /* Cache of MSI-X setup */
 typedef struct VFIOMSIXInfo {
+    uint8_t pos;
     uint8_t table_bar;
     uint8_t pba_bar;
     uint16_t entries;
@@ -128,6 +129,8 @@ struct VFIOPCIDevice {
     unsigned int rom_size;
     off_t rom_offset; /* Offset of ROM region within device fd */
     void *rom;
+    uint8_t msi_pos;
+    uint16_t msi_ctrl;
     int msi_cap_size;
     VFIOMSIVector *msi_vectors;
     VFIOMSIXInfo *msix;
-- 
2.37.3