[Qemu-devel] [PATCH v2] vfio-pci: Fix BAR size overflow

[Qemu-devel] [PATCH v2] vfio-pci: Fix BAR size overflow

[Alex Williamson]

We use an unsigned int when working with the PCI BAR size, which can
obviously overflow if the BAR is 4GB or larger.  This needs to change
to a fixed length uint64_t.  A similar issue is possible, though even
more unlikely, when mapping the region above an MSI-X table.  The
start of the MSI-X vector table must be below 4GB, but the end, and
therefore the start of the next mapping region, could still land at
4GB.

Suggested-by: Nishank Trivedi <nishank.trivedi@netapp.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

v2: s/unsigned long/uint64_t/, duh

 hw/vfio/pci.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index b4e73d1..b6703c7 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2301,7 +2301,7 @@ static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
 static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
 {
     VFIOBAR *bar = &vdev->bars[nr];
-    unsigned size = bar->region.size;
+    uint64_t size = bar->region.size;
     char name[64];
     uint32_t pci_bar;
     uint8_t type;
@@ -2351,7 +2351,7 @@ static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
     }
 
     if (vdev->msix && vdev->msix->table_bar == nr) {
-        unsigned start;
+        uint64_t start;
 
         start = HOST_PAGE_ALIGN(vdev->msix->table_offset +
                                 (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE));

Re: [Qemu-devel] [PATCH v2] vfio-pci: Fix BAR size overflow

[Don Slutz]

On 01/07/15 12:23, Alex Williamson wrote:
> We use an unsigned int when working with the PCI BAR size, which can
> obviously overflow if the BAR is 4GB or larger.  This needs to change
> to a fixed length uint64_t.  A similar issue is possible, though even
> more unlikely, when mapping the region above an MSI-X table.  The
> start of the MSI-X vector table must be below 4GB, but the end, and
> therefore the start of the next mapping region, could still land at
> 4GB.
> 
> Suggested-by: Nishank Trivedi <nishank.trivedi@netapp.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> 

Looks good.

Reviewed-by: Don Slutz <dslutz@verizon.com>

   -Don Slutz

> v2: s/unsigned long/uint64_t/, duh
> 
>  hw/vfio/pci.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index b4e73d1..b6703c7 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2301,7 +2301,7 @@ static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
>  static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>  {
>      VFIOBAR *bar = &vdev->bars[nr];
> -    unsigned size = bar->region.size;
> +    uint64_t size = bar->region.size;
>      char name[64];
>      uint32_t pci_bar;
>      uint8_t type;
> @@ -2351,7 +2351,7 @@ static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>      }
>  
>      if (vdev->msix && vdev->msix->table_bar == nr) {
> -        unsigned start;
> +        uint64_t start;
>  
>          start = HOST_PAGE_ALIGN(vdev->msix->table_offset +
>                                  (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE));
> 
> 

Re: [Qemu-devel] [PATCH v2] vfio-pci: Fix BAR size overflow

[Alexey Kardashevskiy]

On 01/08/2015 04:23 AM, Alex Williamson wrote:
> We use an unsigned int when working with the PCI BAR size, which can
> obviously overflow if the BAR is 4GB or larger.  This needs to change
> to a fixed length uint64_t.  A similar issue is possible, though even
> more unlikely, when mapping the region above an MSI-X table.  The
> start of the MSI-X vector table must be below 4GB, but the end, and
> therefore the start of the next mapping region, could still land at
> 4GB.
> 
> Suggested-by: Nishank Trivedi <nishank.trivedi@netapp.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>	

Helped me with 16GB BARs.


> ---
> 
> v2: s/unsigned long/uint64_t/, duh
> 
>  hw/vfio/pci.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index b4e73d1..b6703c7 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2301,7 +2301,7 @@ static void vfio_unmap_bar(VFIOPCIDevice *vdev, int nr)
>  static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>  {
>      VFIOBAR *bar = &vdev->bars[nr];
> -    unsigned size = bar->region.size;
> +    uint64_t size = bar->region.size;
>      char name[64];
>      uint32_t pci_bar;
>      uint8_t type;
> @@ -2351,7 +2351,7 @@ static void vfio_map_bar(VFIOPCIDevice *vdev, int nr)
>      }
>  
>      if (vdev->msix && vdev->msix->table_bar == nr) {
> -        unsigned start;
> +        uint64_t start;
>  
>          start = HOST_PAGE_ALIGN(vdev->msix->table_offset +
>                                  (vdev->msix->entries * PCI_MSIX_ENTRY_SIZE));
> 
> 


-- 
Alexey