dma: Introduce dma_aligned_pow2_mask()
Currently get_naturally_aligned_size() is used by the intel iommu
to compute the maximum invalidation range based on @size which is
a power of 2 while being aligned with the @start address and less
than the maximum range defined by @gaw.
This helper is also useful for other iommu devices (virtio-iommu,
SMMUv3) to make sure IOMMU UNMAP notifiers only are called with
power of 2 range sizes.
Let's move this latter into dma-helpers.c and rename it into
dma_aligned_pow2_mask(). Also rewrite the helper so that it
accomodates UINT64_MAX values for the size mask and max mask.
It now returns a mask instead of a size. Change the caller.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-id: 20210309102742.30442-3-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/include/sysemu/dma.h b/include/sysemu/dma.h
index a052f7b..3201e79 100644
--- a/include/sysemu/dma.h
+++ b/include/sysemu/dma.h
@@ -296,4 +296,16 @@
void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
QEMUSGList *sg, enum BlockAcctType type);
+/**
+ * dma_aligned_pow2_mask: Return the address bit mask of the largest
+ * power of 2 size less or equal than @end - @start + 1, aligned with @start,
+ * and bounded by 1 << @max_addr_bits bits.
+ *
+ * @start: range start address
+ * @end: range end address (greater than @start)
+ * @max_addr_bits: max address bits (<= 64)
+ */
+uint64_t dma_aligned_pow2_mask(uint64_t start, uint64_t end,
+ int max_addr_bits);
+
#endif
