[PATCH v1 1/4] virtio: protect non-modern devices from too big virtqueue size setting

[Denis Plotnikov <dplotnikov@virtuozzo.com>]

The patch protects from creating illegal virtio device configuration
via direct virtqueue size property setting.

Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
---
 hw/virtio/virtio-blk-pci.c  |  9 +++++++++
 hw/virtio/virtio-scsi-pci.c | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/hw/virtio/virtio-blk-pci.c b/hw/virtio/virtio-blk-pci.c
index 60c9185c39..6177ff1df8 100644
--- a/hw/virtio/virtio-blk-pci.c
+++ b/hw/virtio/virtio-blk-pci.c
@@ -48,6 +48,15 @@ static void virtio_blk_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(vpci_dev);
     DeviceState *vdev = DEVICE(&dev->vdev);
+    bool modern = virtio_pci_modern(vpci_dev);
+    uint32_t queue_size = dev->vdev.conf.queue_size;
+
+    if (!modern && queue_size > 128) {
+        error_setg(errp,
+                   "too big queue size (%u, max: 128) "
+                   "for non-modern virtio device", queue_size);
+        return;
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
         vpci_dev->nvectors = dev->vdev.conf.num_queues + 1;
diff --git a/hw/virtio/virtio-scsi-pci.c b/hw/virtio/virtio-scsi-pci.c
index 2830849729..6e6790fda5 100644
--- a/hw/virtio/virtio-scsi-pci.c
+++ b/hw/virtio/virtio-scsi-pci.c
@@ -17,6 +17,7 @@
 
 #include "hw/virtio/virtio-scsi.h"
 #include "virtio-pci.h"
+#include "qapi/error.h"
 
 typedef struct VirtIOSCSIPCI VirtIOSCSIPCI;
 
@@ -47,6 +48,15 @@ static void virtio_scsi_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
     DeviceState *proxy = DEVICE(vpci_dev);
     char *bus_name;
+    bool modern = virtio_pci_modern(vpci_dev);
+    uint32_t virtqueue_size = vs->conf.virtqueue_size;
+
+    if (!modern && virtqueue_size > 128) {
+        error_setg(errp,
+                   "too big virtqueue size (%u, max: 128) "
+                   "for non-modern virtio device", virtqueue_size);
+        return;
+    }
 
     if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
         vpci_dev->nvectors = vs->conf.num_queues + 3;
-- 
2.17.0