[Qemu-devel] [PATCH qemu] vfio: Fix 128 bit handling when deleting region

[Qemu-devel] [PATCH qemu] vfio: Fix 128 bit handling when deleting region

[Alexey Kardashevskiy]

7532d3cbf "vfio: Fix 128 bit handling" added support for 64bit IOMMU
memory regions when those are added to VFIO address space; however
removing code cannot cope with these as int128_get64() will fail on
1<<64.

This copies 128bit handling from region_add() to region_del().

Since the only machine type which is actually going to use 64bit IOMMU
is pseries and it never really removes them (instead it will dynamically
add/remove subregions), this should cause no behavioral change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/vfio/common.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index f27db36..fe5ec6a 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -430,6 +430,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
 {
     VFIOContainer *container = container_of(listener, VFIOContainer, listener);
     hwaddr iova, end;
+    Int128 llend, llsize;
     int ret;
 
     if (vfio_listener_skipped_section(section)) {
@@ -468,21 +469,25 @@ static void vfio_listener_region_del(MemoryListener *listener,
     }
 
     iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
-    end = (section->offset_within_address_space + int128_get64(section->size)) &
-          TARGET_PAGE_MASK;
+    llend = int128_make64(section->offset_within_address_space);
+    llend = int128_add(llend, section->size);
+    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
 
-    if (iova >= end) {
+    if (int128_ge(int128_make64(iova), llend)) {
         return;
     }
+    end = int128_get64(int128_sub(llend, int128_one()));
 
-    trace_vfio_listener_region_del(iova, end - 1);
+    llsize = int128_sub(llend, int128_make64(iova));
 
-    ret = vfio_dma_unmap(container, iova, end - iova);
+    trace_vfio_listener_region_del(iova, end);
+
+    ret = vfio_dma_unmap(container, iova, int128_get64(llsize));
     memory_region_unref(section->mr);
     if (ret) {
         error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
                      "0x%"HWADDR_PRIx") = %d (%m)",
-                     container, iova, end - iova, ret);
+                     container, iova, int128_get64(llsize), ret);
     }
 }
 
-- 
2.5.0.rc3

Re: [Qemu-devel] [PATCH qemu] vfio: Fix 128 bit handling when deleting region

[Alexey Kardashevskiy]

On 05/05/2016 11:31 AM, Alexey Kardashevskiy wrote:
> 7532d3cbf "vfio: Fix 128 bit handling" added support for 64bit IOMMU
> memory regions when those are added to VFIO address space; however
> removing code cannot cope with these as int128_get64() will fail on
> 1<<64.
>
> This copies 128bit handling from region_add() to region_del().
>
> Since the only machine type which is actually going to use 64bit IOMMU
> is pseries and it never really removes them (instead it will dynamically
> add/remove subregions), this should cause no behavioral change.

Ping?


>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>  hw/vfio/common.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index f27db36..fe5ec6a 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -430,6 +430,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
>  {
>      VFIOContainer *container = container_of(listener, VFIOContainer, listener);
>      hwaddr iova, end;
> +    Int128 llend, llsize;
>      int ret;
>
>      if (vfio_listener_skipped_section(section)) {
> @@ -468,21 +469,25 @@ static void vfio_listener_region_del(MemoryListener *listener,
>      }
>
>      iova = TARGET_PAGE_ALIGN(section->offset_within_address_space);
> -    end = (section->offset_within_address_space + int128_get64(section->size)) &
> -          TARGET_PAGE_MASK;
> +    llend = int128_make64(section->offset_within_address_space);
> +    llend = int128_add(llend, section->size);
> +    llend = int128_and(llend, int128_exts64(TARGET_PAGE_MASK));
>
> -    if (iova >= end) {
> +    if (int128_ge(int128_make64(iova), llend)) {
>          return;
>      }
> +    end = int128_get64(int128_sub(llend, int128_one()));
>
> -    trace_vfio_listener_region_del(iova, end - 1);
> +    llsize = int128_sub(llend, int128_make64(iova));
>
> -    ret = vfio_dma_unmap(container, iova, end - iova);
> +    trace_vfio_listener_region_del(iova, end);
> +
> +    ret = vfio_dma_unmap(container, iova, int128_get64(llsize));
>      memory_region_unref(section->mr);
>      if (ret) {
>          error_report("vfio_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>                       "0x%"HWADDR_PRIx") = %d (%m)",
> -                     container, iova, end - iova, ret);
> +                     container, iova, int128_get64(llsize), ret);
>      }
>  }
>
>


-- 
Alexey