address_space_read: address_space_to_flatview needs RCU lock
address_space_read is calling address_space_to_flatview but it can
be called outside the RCU lock. To fix it, push the rcu_read_lock/unlock
pair up from flatview_read_full to address_space_read's constant size
fast path and address_space_read_full.
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 4b65b56..31eae0a 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1917,13 +1917,12 @@
/* Internal functions, part of the implementation of address_space_read. */
+MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr,
+ MemTxAttrs attrs, uint8_t *buf, int len);
MemTxResult flatview_read_continue(FlatView *fv, hwaddr addr,
MemTxAttrs attrs, uint8_t *buf,
int len, hwaddr addr1, hwaddr l,
MemoryRegion *mr);
-
-MemTxResult flatview_read_full(FlatView *fv, hwaddr addr,
- MemTxAttrs attrs, uint8_t *buf, int len);
void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr);
static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write)
@@ -1942,25 +1941,28 @@
*
* Return a MemTxResult indicating whether the operation succeeded
* or failed (eg unassigned memory, device rejected the transaction,
- * IOMMU fault).
+ * IOMMU fault). Called within RCU critical section.
*
- * @fv: #FlatView to be accessed
+ * @as: #AddressSpace to be accessed
* @addr: address within that address space
* @attrs: memory transaction attributes
* @buf: buffer with the data transferred
*/
static inline __attribute__((__always_inline__))
-MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
- uint8_t *buf, int len)
+MemTxResult address_space_read(AddressSpace *as, hwaddr addr,
+ MemTxAttrs attrs, uint8_t *buf,
+ int len)
{
MemTxResult result = MEMTX_OK;
hwaddr l, addr1;
void *ptr;
MemoryRegion *mr;
+ FlatView *fv;
if (__builtin_constant_p(len)) {
if (len) {
rcu_read_lock();
+ fv = address_space_to_flatview(as);
l = len;
mr = flatview_translate(fv, addr, &addr1, &l, false);
if (len == l && memory_access_is_direct(mr, false)) {
@@ -1973,18 +1975,11 @@
rcu_read_unlock();
}
} else {
- result = flatview_read_full(fv, addr, attrs, buf, len);
+ result = address_space_read_full(as, addr, attrs, buf, len);
}
return result;
}
-static inline MemTxResult address_space_read(AddressSpace *as, hwaddr addr,
- MemTxAttrs attrs, uint8_t *buf,
- int len)
-{
- return flatview_read(address_space_to_flatview(as), addr, attrs, buf, len);
-}
-
/**
* address_space_read_cached: read from a cached RAM region
*
