Skip to content
  1. Oct 25, 2013
  3. Oct 10, 2013
    • Stefano Stabellini's avatar
      swiotlb-xen: use xen_alloc/free_coherent_pages · 1b65c4e5
      Stefano Stabellini authored 
      

Use xen_alloc_coherent_pages and xen_free_coherent_pages to allocate or
free coherent pages.

We need to be careful handling the pointer returned by
xen_alloc_coherent_pages, because on ARM the pointer is not equal to
phys_to_virt(*dma_handle). In fact virt_to_phys only works for kernel
direct mapped RAM memory.
In ARM case the pointer could be an ioremap address, therefore passing
it to virt_to_phys would give you another physical address that doesn't
correspond to it.

Make xen_create_contiguous_region take a phys_addr_t as start parameter to
avoid the virt_to_phys calls which would be incorrect.

Changes in v6:
- remove extra spaces.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      1b65c4e5
    • Stefano Stabellini's avatar
      xen: introduce xen_alloc/free_coherent_pages · d6fe76c5
      Stefano Stabellini authored 
      

xen_swiotlb_alloc_coherent needs to allocate a coherent buffer for cpu
and devices. On native x86 is sufficient to call __get_free_pages in
order to get a coherent buffer, while on ARM (and potentially ARM64) we
need to call the native dma_ops->alloc implementation.

Introduce xen_alloc_coherent_pages to abstract the arch specific buffer
allocation.

Similarly introduce xen_free_coherent_pages to free a coherent buffer:
on x86 is simply a call to free_pages while on ARM and ARM64 is
arm_dma_ops.free.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>


Changes in v7:
- rename __get_dma_ops to __generic_dma_ops;
- call __generic_dma_ops(hwdev)->alloc/free on arm64 too.

Changes in v6:
- call __get_dma_ops to get the native dma_ops pointer on arm.
      d6fe76c5
  5. Oct 19, 2013
  7. Oct 10, 2013
  9. Oct 18, 2013
    • Stefano Stabellini's avatar
      arm/xen,arm64/xen: introduce p2m · 4a19138c
      Stefano Stabellini authored 
      

Introduce physical to machine and machine to physical tracking
mechanisms based on rbtrees for arm/xen and arm64/xen.

We need it because any guests on ARM are an autotranslate guests,
therefore a physical address is potentially different from a machine
address. When programming a device to do DMA, we need to be
extra-careful to use machine addresses rather than physical addresses to
program the device. Therefore we need to know the physical to machine
mappings.

For the moment we assume that dom0 starts with a 1:1 physical to machine
mapping, in other words physical addresses correspond to machine
addresses. However when mapping a foreign grant reference, obviously the
1:1 model doesn't work anymore. So at the very least we need to be able
to track grant mappings.

We need locking to protect accesses to the two trees.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>

Changes in v8:
- move pfn_to_mfn and mfn_to_pfn to page.h as static inline functions;
- no need to walk the tree if phys_to_mach.rb_node is NULL;
- correctly handle multipage p2m entries;
- substitute the spin_lock with a rwlock.
      4a19138c
  11. Oct 15, 2013
  13. Oct 14, 2013
  15. Oct 13, 2013