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xen: import new ring macros in ring.h
Sync the ring.h file with upstream Xen, to introduce the new ring macros. They will be used by the Xen transport for 9pfs. CC: konrad.wilk@oracle.com CC: boris.ostrovsky@oracle.com CC: jgross@suse.com CC: groug@kaod.org Signed-off-by: Stefano Stabellini <stefano@aporeto.com> Acked-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Stefano Stabellini
Juergen Gross
parent
ab1570a427
commit
564f7dfde2
@ -283,4 +283,147 @@ struct __name##_back_ring { \
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(_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r); \
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} while (0)
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/*
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* DEFINE_XEN_FLEX_RING_AND_INTF defines two monodirectional rings and
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* functions to check if there is data on the ring, and to read and
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* write to them.
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*
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* DEFINE_XEN_FLEX_RING is similar to DEFINE_XEN_FLEX_RING_AND_INTF, but
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* does not define the indexes page. As different protocols can have
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* extensions to the basic format, this macro allow them to define their
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* own struct.
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*
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* XEN_FLEX_RING_SIZE
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* Convenience macro to calculate the size of one of the two rings
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* from the overall order.
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*
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* $NAME_mask
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* Function to apply the size mask to an index, to reduce the index
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* within the range [0-size].
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*
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* $NAME_read_packet
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* Function to read data from the ring. The amount of data to read is
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* specified by the "size" argument.
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*
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* $NAME_write_packet
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* Function to write data to the ring. The amount of data to write is
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* specified by the "size" argument.
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*
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* $NAME_get_ring_ptr
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* Convenience function that returns a pointer to read/write to the
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* ring at the right location.
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*
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* $NAME_data_intf
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* Indexes page, shared between frontend and backend. It also
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* contains the array of grant refs.
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*
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* $NAME_queued
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* Function to calculate how many bytes are currently on the ring,
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* ready to be read. It can also be used to calculate how much free
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* space is currently on the ring (XEN_FLEX_RING_SIZE() -
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* $NAME_queued()).
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*/
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#ifndef XEN_PAGE_SHIFT
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/* The PAGE_SIZE for ring protocols and hypercall interfaces is always
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* 4K, regardless of the architecture, and page granularity chosen by
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* operating systems.
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*/
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#define XEN_PAGE_SHIFT 12
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#endif
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#define XEN_FLEX_RING_SIZE(order) \
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(1UL << ((order) + XEN_PAGE_SHIFT - 1))
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#define DEFINE_XEN_FLEX_RING(name) \
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static inline RING_IDX name##_mask(RING_IDX idx, RING_IDX ring_size) \
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{ \
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return idx & (ring_size - 1); \
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} \
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\
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static inline unsigned char *name##_get_ring_ptr(unsigned char *buf, \
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RING_IDX idx, \
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RING_IDX ring_size) \
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{ \
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return buf + name##_mask(idx, ring_size); \
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} \
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\
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static inline void name##_read_packet(void *opaque, \
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const unsigned char *buf, \
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size_t size, \
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RING_IDX masked_prod, \
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RING_IDX *masked_cons, \
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RING_IDX ring_size) \
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{ \
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if (*masked_cons < masked_prod || \
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size <= ring_size - *masked_cons) { \
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memcpy(opaque, buf + *masked_cons, size); \
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} else { \
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memcpy(opaque, buf + *masked_cons, ring_size - *masked_cons); \
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memcpy((unsigned char *)opaque + ring_size - *masked_cons, buf, \
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size - (ring_size - *masked_cons)); \
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} \
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*masked_cons = name##_mask(*masked_cons + size, ring_size); \
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} \
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\
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static inline void name##_write_packet(unsigned char *buf, \
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const void *opaque, \
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size_t size, \
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RING_IDX *masked_prod, \
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RING_IDX masked_cons, \
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RING_IDX ring_size) \
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{ \
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if (*masked_prod < masked_cons || \
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size <= ring_size - *masked_prod) { \
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memcpy(buf + *masked_prod, opaque, size); \
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} else { \
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memcpy(buf + *masked_prod, opaque, ring_size - *masked_prod); \
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memcpy(buf, (unsigned char *)opaque + (ring_size - *masked_prod), \
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size - (ring_size - *masked_prod)); \
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} \
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*masked_prod = name##_mask(*masked_prod + size, ring_size); \
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} \
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\
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static inline RING_IDX name##_queued(RING_IDX prod, \
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RING_IDX cons, \
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RING_IDX ring_size) \
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{ \
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RING_IDX size; \
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\
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if (prod == cons) \
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return 0; \
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\
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prod = name##_mask(prod, ring_size); \
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cons = name##_mask(cons, ring_size); \
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\
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if (prod == cons) \
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return ring_size; \
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\
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if (prod > cons) \
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size = prod - cons; \
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else \
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size = ring_size - (cons - prod); \
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return size; \
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} \
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\
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struct name##_data { \
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unsigned char *in; /* half of the allocation */ \
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unsigned char *out; /* half of the allocation */ \
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}
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#define DEFINE_XEN_FLEX_RING_AND_INTF(name) \
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struct name##_data_intf { \
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RING_IDX in_cons, in_prod; \
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\
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uint8_t pad1[56]; \
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\
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RING_IDX out_cons, out_prod; \
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\
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uint8_t pad2[56]; \
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\
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RING_IDX ring_order; \
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grant_ref_t ref[]; \
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}; \
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DEFINE_XEN_FLEX_RING(name)
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#endif /* __XEN_PUBLIC_IO_RING_H__ */
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