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Subject[PATCH RFC 5/8] xen: introduce XENMEM_get_dma_buf and xen_put_dma_buf
Date
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
include/xen/interface/memory.h | 62 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index 2ecfe4f..ffd7f4e 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -263,4 +263,66 @@ struct xen_remove_from_physmap {
};
DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);

+#define XENMEM_get_dma_buf 26
+/*
+ * This hypercall is similar to XENMEM_exchange: it exchanges the pages
+ * passed in with a new set of pages, contiguous and under 4G if so
+ * requested. The new pages are going to be "pinned": it's guaranteed
+ * that their p2m mapping won't be changed until explicitly "unpinned".
+ * If return code is zero then @out.extent_list provides the MFNs of the
+ * newly-allocated memory. Returns zero on complete success, otherwise
+ * a negative error code.
+ * On complete success then always @nr_exchanged == @in.nr_extents. On
+ * partial success @nr_exchanged indicates how much work was done.
+ */
+struct xen_get_dma_buf {
+ /*
+ * [IN] Details of memory extents to be exchanged (GMFN bases).
+ * Note that @in.address_bits is ignored and unused.
+ */
+ struct xen_memory_reservation in;
+
+ /*
+ * [IN/OUT] Details of new memory extents.
+ * We require that:
+ * 1. @in.domid == @out.domid
+ * 2. @in.nr_extents << @in.extent_order ==
+ * @out.nr_extents << @out.extent_order
+ * 3. @in.extent_start and @out.extent_start lists must not overlap
+ * 4. @out.extent_start lists GPFN bases to be populated
+ * 5. @out.extent_start is overwritten with allocated GMFN bases
+ */
+ struct xen_memory_reservation out;
+
+ /*
+ * [OUT] Number of input extents that were successfully exchanged:
+ * 1. The first @nr_exchanged input extents were successfully
+ * deallocated.
+ * 2. The corresponding first entries in the output extent list correctly
+ * indicate the GMFNs that were successfully exchanged.
+ * 3. All other input and output extents are untouched.
+ * 4. If not all input exents are exchanged then the return code of this
+ * command will be non-zero.
+ * 5. THIS FIELD MUST BE INITIALISED TO ZERO BY THE CALLER!
+ */
+ xen_ulong_t nr_exchanged;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_get_dma_buf);
+
+#define XENMEM_put_dma_buf 27
+/*
+ * XENMEM_put_dma_buf unpins a set of pages, previously pinned by
+ * XENMEM_get_dma_buf. After this call the p2m mapping of the pages can
+ * be transparently changed by the hypervisor, as usual. The pages are
+ * still accessible from the guest.
+ */
+struct xen_put_dma_buf {
+ /*
+ * [IN] Details of memory extents to be exchanged (GMFN bases).
+ * Note that @in.address_bits is ignored and unused.
+ */
+ struct xen_memory_reservation in;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_put_dma_buf);
+
#endif /* __XEN_PUBLIC_MEMORY_H__ */
--
1.7.2.5


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