From b2a44fcad74f1cc7a6786d38eba7db12ab2352ba Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 5 Mar 2018 00:19:49 +0100 Subject: 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 Signed-off-by: Paolo Bonzini --- include/exec/memory.h | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) (limited to 'include/exec') diff --git a/include/exec/memory.h b/include/exec/memory.h index 4b65b566cb..31eae0a640 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -1917,13 +1917,12 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, /* 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 @@ static inline bool memory_access_is_direct(MemoryRegion *mr, bool is_write) * * 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 @@ MemTxResult flatview_read(FlatView *fv, hwaddr addr, MemTxAttrs attrs, 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 * -- cgit v1.2.1