[Qemu-devel] [PATCH 2/2] pci-assign: Fix memory out of bound when MSI-X table not fit in a single page

[arei.gonglei]

From: Gonglei <arei.gong...@huawei.com>

QEMU only mmap MSIX_PAGE_SIZE memory for all pci devices in
assigned_dev_register_msix_mmio(), meanwhile the set the one
page memmory to zero, so the rest memory will be random value
(maybe etnry.data is not 0). In the assigned_dev_update_msix_mmio()
maybe occur the issue of entry_nr > 256, and the kmod reports
the EINVAL error.

Signed-off-by: Gonglei <arei.gong...@huawei.com>
---
 hw/i386/kvm/pci-assign.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/hw/i386/kvm/pci-assign.c b/hw/i386/kvm/pci-assign.c
index 570333f..d25a19e 100644
--- a/hw/i386/kvm/pci-assign.c
+++ b/hw/i386/kvm/pci-assign.c
@@ -37,6 +37,7 @@
 #include "hw/pci/pci.h"
 #include "hw/pci/msi.h"
 #include "kvm_i386.h"
+#include "qemu/osdep.h"
 
 #define MSIX_PAGE_SIZE 0x1000
 
@@ -59,6 +60,9 @@
 #define DEBUG(fmt, ...)
 #endif
 
+/* the msix-table size readed from pci device config */
+static int msix_table_size;
+
 typedef struct PCIRegion {
     int type;           /* Memory or port I/O */
     int valid;
@@ -1604,7 +1608,12 @@ static void assigned_dev_msix_reset(AssignedDevice *dev)
 
 static int assigned_dev_register_msix_mmio(AssignedDevice *dev)
 {
-    dev->msix_table = mmap(NULL, MSIX_PAGE_SIZE, PROT_READ|PROT_WRITE,
+    msix_table_size = ROUND_UP(dev->msix_max * sizeof(struct MSIXTableEntry),
+                                MSIX_PAGE_SIZE);
+
+    DEBUG("msix_table_size: 0x%x\n", msix_table_size);
+
+    dev->msix_table = mmap(NULL, msix_table_size, PROT_READ|PROT_WRITE,
                            MAP_ANONYMOUS|MAP_PRIVATE, 0, 0);
     if (dev->msix_table == MAP_FAILED) {
         error_report("fail allocate msix_table! %s", strerror(errno));
@@ -1615,7 +1624,7 @@ static int assigned_dev_register_msix_mmio(AssignedDevice 
*dev)
     assigned_dev_msix_reset(dev);
 
     memory_region_init_io(&dev->mmio, OBJECT(dev), &assigned_dev_msix_mmio_ops,
-                          dev, "assigned-dev-msix", MSIX_PAGE_SIZE);
+                          dev, "assigned-dev-msix", msix_table_size);
     return 0;
 }
 
@@ -1627,7 +1636,7 @@ static void 
assigned_dev_unregister_msix_mmio(AssignedDevice *dev)
 
     memory_region_destroy(&dev->mmio);
 
-    if (munmap(dev->msix_table, MSIX_PAGE_SIZE) == -1) {
+    if (munmap(dev->msix_table, msix_table_size) == -1) {
         error_report("error unmapping msix_table! %s", strerror(errno));
     }
     dev->msix_table = NULL;
-- 
1.7.12.4