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exec: introduce address_space_get_iotlb_entry()

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This patch introduces a helper to query the iotlb entry for a
possible iova. This will be used by later device IOTLB API to enable
the capability for a dataplane (e.g vhost) to query the IOTLB.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2016-12-30 18:09:13 +08:00 • committed by Michael S. Tsirkin
parent 2d3fc5816e
commit 052c8fa998
2 changed files with 38 additions and 0 deletions
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33
exec.c
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@ -448,6 +448,39 @@ address_space_translate_internal(AddressSpaceDispatch *d, hwaddr addr, hwaddr *x
return section;
}
/* Called from RCU critical section */
IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr,
bool is_write)
{
IOMMUTLBEntry iotlb = {0};
MemoryRegionSection *section;
MemoryRegion *mr;
for (;;) {
AddressSpaceDispatch *d = atomic_rcu_read(&as->dispatch);
section = address_space_lookup_region(d, addr, false);
addr = addr - section->offset_within_address_space
+ section->offset_within_region;
mr = section->mr;
if (!mr->iommu_ops) {
break;
}
iotlb = mr->iommu_ops->translate(mr, addr, is_write);
if (!(iotlb.perm & (1 << is_write))) {
iotlb.target_as = NULL;
break;
}
addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
| (addr & iotlb.addr_mask));
as = iotlb.target_as;
}
return iotlb;
}
/* Called from RCU critical section */
MemoryRegion *address_space_translate(AddressSpace *as, hwaddr addr,
hwaddr *xlat, hwaddr *plen,