Skip vfio mmap bar regions during memory dump

The PCI MMIO might be disabled or the device in the reset state.
Make sure we do not dump these memory regions.

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/misc/vfio.c        |  2 +-
 include/exec/memory.h | 27 +++++++++++++++++++++++++++
 memory.c              | 16 ++++++++++++++++
 memory_mapping.c      |  3 ++-
 4 files changed, 46 insertions(+), 2 deletions(-)

On Fri, 2014-09-12 at 10:12 +0530, Nikunj A Dadhania wrote:
> The PCI MMIO might be disabled or the device in the reset state.
> Make sure we do not dump these memory regions.
> 
> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
> ---

If you don't want to dump a memory region then add the ability to set a
no-dump flag on the region and have vfio call it, don't make something
as specific as a vfio mmap region.  Thanks,

Alex

>  hw/misc/vfio.c        |  2 +-
>  include/exec/memory.h | 27 +++++++++++++++++++++++++++
>  memory.c              | 16 ++++++++++++++++
>  memory_mapping.c      |  3 ++-
>  4 files changed, 46 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index d69bb29..fd6dbe9 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -2721,7 +2721,7 @@ static int vfio_mmap_bar(VFIODevice *vdev, VFIOBAR *bar,
>              goto empty_region;
>          }
>  
> -        memory_region_init_ram_ptr(submem, OBJECT(vdev), name, size, *map);
> +        memory_region_init_vfio_mmap(submem, OBJECT(vdev), name, size, *map);
>      } else {
>  empty_region:
>          /* Create a zero sized sub-region to make cleanup easy. */
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index fc6e93d..e184df6 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -144,6 +144,7 @@ struct MemoryRegion {
>      bool terminates;
>      bool romd_mode;
>      bool ram;
> +    bool vfio_mmap;
>      bool readonly; /* For RAM regions */
>      bool enabled;
>      bool rom_device;
> @@ -329,6 +330,23 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
>                                  void *ptr);
>  
>  /**
> + * memory_region_init_vfio_mmap:  Initialize VFIO mmap memory region from a
> + *                                user-provided pointer.  Accesses into the
> + *                                region will modify memory directly.
> + *
> + * @mr: the #MemoryRegion to be initialized.
> + * @owner: the object that tracks the region's reference count
> + * @name: the name of the region.
> + * @size: size of the region.
> + * @ptr: memory to be mapped; must contain at least @size bytes.
> + */
> +void memory_region_init_vfio_mmap(MemoryRegion *mr,
> +                                  struct Object *owner,
> +                                  const char *name,
> +                                  uint64_t size,
> +                                  void *ptr);
> +
> +/**
>   * memory_region_init_alias: Initialize a memory region that aliases all or a
>   *                           part of another memory region.
>   *
> @@ -434,6 +452,15 @@ uint64_t memory_region_size(MemoryRegion *mr);
>  bool memory_region_is_ram(MemoryRegion *mr);
>  
>  /**
> + * memory_region_is_vfio_mmap: check whether a memory region is VFIO mmap
> + *
> + * Returns %true is a memory region is VFIO.
> + *
> + * @mr: the memory region being queried
> + */
> +bool memory_region_is_vfio_mmap(MemoryRegion *mr);
> +
> +/**
>   * memory_region_is_romd: check whether a memory region is in ROMD mode
>   *
>   * Returns %true if a memory region is a ROM device and currently set to allow
> diff --git a/memory.c b/memory.c
> index 664d3e6..63eadaa 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -847,6 +847,7 @@ void memory_region_init(MemoryRegion *mr,
>      mr->enabled = true;
>      mr->terminates = false;
>      mr->ram = false;
> +    mr->vfio_mmap = false;
>      mr->romd_mode = true;
>      mr->readonly = false;
>      mr->rom_device = false;
> @@ -1032,6 +1033,16 @@ void memory_region_init_ram_ptr(MemoryRegion *mr,
>      mr->ram_addr = qemu_ram_alloc_from_ptr(size, ptr, mr);
>  }
>  
> +void memory_region_init_vfio_mmap(MemoryRegion *mr,
> +                                  Object *owner,
> +                                  const char *name,
> +                                  uint64_t size,
> +                                  void *ptr)
> +{
> +    memory_region_init_ram_ptr(mr, owner, name, size, ptr);
> +    mr->vfio_mmap = true;
> +}
> +
>  void memory_region_init_alias(MemoryRegion *mr,
>                                Object *owner,
>                                const char *name,
> @@ -1129,6 +1140,11 @@ bool memory_region_is_ram(MemoryRegion *mr)
>      return mr->ram;
>  }
>  
> +bool memory_region_is_vfio_mmap(MemoryRegion *mr)
> +{
> +    return mr->vfio_mmap;
> +}
> +
>  bool memory_region_is_logging(MemoryRegion *mr)
>  {
>      return mr->dirty_log_mask;
> diff --git a/memory_mapping.c b/memory_mapping.c
> index 87a6ed5..64ef46d 100644
> --- a/memory_mapping.c
> +++ b/memory_mapping.c
> @@ -203,7 +203,8 @@ static void guest_phys_blocks_region_add(MemoryListener *listener,
>      GuestPhysBlock *predecessor;
>  
>      /* we only care about RAM */
> -    if (!memory_region_is_ram(section->mr)) {
> +    if (!memory_region_is_ram(section->mr) ||
> +        memory_region_is_vfio_mmap(section->mr)) {
>          return;
>      }
>

Alex Williamson <alex.williamson@redhat.com> writes:

> On Fri, 2014-09-12 at 10:12 +0530, Nikunj A Dadhania wrote:
>> The PCI MMIO might be disabled or the device in the reset state.
>> Make sure we do not dump these memory regions.
>> 
>> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
>> ---
>
> If you don't want to dump a memory region then add the ability to set a
> no-dump flag on the region and have vfio call it, don't make something
> as specific as a vfio mmap region.  Thanks,

Sure, do you want me to separate it to two patches:

1) Adding skip_dump flag and accessors
2) VFIO using the accessors?

Regards,
Nikunj