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[Qemu-devel] [PATCH 29/30] exec: add a reference to the region returned
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 29/30] exec: add a reference to the region returned by address_space_translate |
Date: |
Fri, 28 Jun 2013 20:26:48 +0200 |
Once address_space_translate will only be protected by RCU, the returned
MemoryRegion might disappear as soon as the RCU read-side critical section
ends. Avoid this by adding a reference to the region, and dropping it
in the caller of address_space_translate.
This generalizes what was done for address_space_map to other callers of
address_space_translate. It is necessary to call address_space_translate
out of the BQL.
Signed-off-by: Paolo Bonzini <address@hidden>
---
exec.c | 19 +++++++++++++++----
include/exec/memory.h | 3 ++-
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/exec.c b/exec.c
index 3e1a576..e564014 100644
--- a/exec.c
+++ b/exec.c
@@ -302,6 +302,7 @@ MemoryRegion *address_space_translate(AddressSpace *as,
hwaddr addr,
*plen = len;
*xlat = addr;
+ memory_region_ref(mr);
return mr;
}
@@ -1990,6 +1991,7 @@ bool address_space_rw(AddressSpace *as, hwaddr addr,
uint8_t *buf,
memcpy(buf, ptr, l);
}
}
+ memory_region_unref(mr);
len -= l;
buf += l;
addr += l;
@@ -2146,7 +2148,7 @@ void *address_space_map(AddressSpace *as,
bounce.addr = addr;
bounce.len = l;
- memory_region_ref(mr);
+ /* Keep the reference to mr until address_space_unmap. */
bounce.mr = mr;
if (!is_write) {
address_space_read(as, addr, bounce.buffer, l);
@@ -2169,12 +2171,13 @@ void *address_space_map(AddressSpace *as,
l = len;
this_mr = address_space_translate(as, addr, &xlat, &l, is_write);
+ memory_region_unref(this_mr);
if (this_mr != mr || xlat != base + done) {
break;
}
}
- memory_region_ref(mr);
+ /* Keep the reference to mr until address_space_unmap. */
*plen = done;
return qemu_ram_ptr_length(raddr + base, plen);
}
@@ -2272,6 +2275,7 @@ static inline uint32_t ldl_phys_internal(hwaddr addr,
break;
}
}
+ memory_region_unref(mr);
return val;
}
@@ -2331,6 +2335,7 @@ static inline uint64_t ldq_phys_internal(hwaddr addr,
break;
}
}
+ memory_region_unref(mr);
return val;
}
@@ -2398,6 +2403,7 @@ static inline uint32_t lduw_phys_internal(hwaddr addr,
break;
}
}
+ memory_region_unref(mr);
return val;
}
@@ -2445,6 +2451,7 @@ void stl_phys_notdirty(hwaddr addr, uint32_t val)
}
}
}
+ memory_region_unref(mr);
}
/* warning: addr must be aligned */
@@ -2486,6 +2493,7 @@ static inline void stl_phys_internal(hwaddr addr,
uint32_t val,
}
invalidate_and_set_dirty(addr1, 4);
}
+ memory_region_unref(mr);
}
void stl_phys(hwaddr addr, uint32_t val)
@@ -2549,6 +2557,7 @@ static inline void stw_phys_internal(hwaddr addr,
uint32_t val,
}
invalidate_and_set_dirty(addr1, 2);
}
+ memory_region_unref(mr);
}
void stw_phys(hwaddr addr, uint32_t val)
@@ -2638,11 +2647,13 @@ bool cpu_physical_memory_is_io(hwaddr phys_addr)
{
MemoryRegion*mr;
hwaddr l = 1;
+ bool res;
mr = address_space_translate(&address_space_memory,
phys_addr, &phys_addr, &l, false);
- return !(memory_region_is_ram(mr) ||
- memory_region_is_romd(mr));
+ res = !(memory_region_is_ram(mr) || memory_region_is_romd(mr));
+ memory_region_unref(mr);
+ return res;
}
#endif
diff --git a/include/exec/memory.h b/include/exec/memory.h
index b21a460..66226b1 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -986,7 +986,8 @@ bool address_space_write(AddressSpace *as, hwaddr addr,
bool address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len);
/* address_space_translate: translate an address range into an address space
- * into a MemoryRegion and an address range into that section
+ * into a MemoryRegion and an address range into that section. Add a reference
+ * to that region.
*
* @as: #AddressSpace to be accessed
* @addr: address within that address space
--
1.8.1.4
- [Qemu-devel] [PATCH 18/30] memory: protect current_map by RCU, (continued)
- [Qemu-devel] [PATCH 18/30] memory: protect current_map by RCU, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 20/30] exec: change well-known physical sections to macros, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 21/30] exec: separate current memory map from the one being built, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 22/30] memory: move MemoryListener declaration earlier, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 23/30] exec: move listener from AddressSpaceDispatch to AddressSpace, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 24/30] exec: separate current radix tree from the one being built, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 26/30] exec: remove cur_map, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 25/30] exec: put memory map in AddressSpaceDispatch, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 27/30] exec: change some APIs to take AddressSpaceDispatch, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 28/30] exec: change iotlb APIs to take AddressSpaceDispatch, Paolo Bonzini, 2013/06/28
- [Qemu-devel] [PATCH 29/30] exec: add a reference to the region returned by address_space_translate,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 30/30] exec: put address space dispatch under RCU critical section, Paolo Bonzini, 2013/06/28