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[Qemu-devel] [PULL 18/34] address_space_read: address_space_to_flatview
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 18/34] address_space_read: address_space_to_flatview needs RCU lock |
Date: |
Tue, 6 Mar 2018 14:19:14 +0100 |
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 <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
exec.c | 38 +++++++++++++++++++++++++-------------
include/exec/memory.h | 25 ++++++++++---------------
2 files changed, 35 insertions(+), 28 deletions(-)
diff --git a/exec.c b/exec.c
index ec91162..e4552ee 100644
--- a/exec.c
+++ b/exec.c
@@ -2616,6 +2616,8 @@ static const MemoryRegionOps watch_mem_ops = {
},
};
+static MemTxResult flatview_read(FlatView *fv, hwaddr addr,
+ MemTxAttrs attrs, uint8_t *buf, int len);
static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
const uint8_t *buf, int len);
static bool flatview_access_valid(FlatView *fv, hwaddr addr, int len,
@@ -3165,24 +3167,18 @@ MemTxResult flatview_read_continue(FlatView *fv, hwaddr
addr,
return result;
}
-MemTxResult flatview_read_full(FlatView *fv, hwaddr addr,
- MemTxAttrs attrs, uint8_t *buf, int len)
+/* Called from RCU critical section. */
+static MemTxResult flatview_read(FlatView *fv, hwaddr addr,
+ MemTxAttrs attrs, uint8_t *buf, int len)
{
hwaddr l;
hwaddr addr1;
MemoryRegion *mr;
- MemTxResult result = MEMTX_OK;
-
- if (len > 0) {
- rcu_read_lock();
- l = len;
- mr = flatview_translate(fv, addr, &addr1, &l, false);
- result = flatview_read_continue(fv, addr, attrs, buf, len,
- addr1, l, mr);
- rcu_read_unlock();
- }
- return result;
+ l = len;
+ mr = flatview_translate(fv, addr, &addr1, &l, false);
+ return flatview_read_continue(fv, addr, attrs, buf, len,
+ addr1, l, mr);
}
static MemTxResult flatview_rw(FlatView *fv, hwaddr addr, MemTxAttrs attrs,
@@ -3203,6 +3199,22 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr
addr,
addr, attrs, buf, len, is_write);
}
+MemTxResult address_space_read_full(AddressSpace *as, hwaddr addr,
+ MemTxAttrs attrs, uint8_t *buf, int len)
+{
+ MemTxResult result = MEMTX_OK;
+ FlatView *fv;
+
+ if (len > 0) {
+ rcu_read_lock();
+ fv = address_space_to_flatview(as);
+ result = flatview_read(fv, addr, attrs, buf, len);
+ rcu_read_unlock();
+ }
+
+ return result;
+}
+
MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
MemTxAttrs attrs,
const uint8_t *buf, int len)
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 @@ 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
*
--
1.8.3.1
- [Qemu-devel] [PULL 09/34] qmp: Add qom-list-properties to list QOM object properties, (continued)
- [Qemu-devel] [PULL 09/34] qmp: Add qom-list-properties to list QOM object properties, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 13/34] sdhci-test: fix leaks, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 14/34] chardev: fix leak in tcp_chr_telnet_init_io(), Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 12/34] ahci-test: fix opts leak of skip tests, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 15/34] openpic_kvm: drop address_space_to_flatview call, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 19/34] address_space_access_valid: address_space_to_flatview needs RCU lock, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 17/34] address_space_write: address_space_to_flatview needs RCU lock, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 22/34] checkpatch: add a warning for basename/dirname, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 18/34] address_space_read: address_space_to_flatview needs RCU lock,
Paolo Bonzini <=
- [Qemu-devel] [PULL 16/34] memory: inline some performance-sensitive accessors, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 20/34] address_space_map: address_space_to_flatview needs RCU lock, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 21/34] address_space_rw: address_space_to_flatview needs RCU lock, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 23/34] checkpatch: add check for `while` and `for`, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 24/34] Revert "build-sys: compile with -Og or -O1 when --enable-debug", Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 25/34] Fixing WHPX casing to match SDK, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 27/34] Remove unnecessary WHPX __debugbreak();, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 26/34] Resolves WHPX breaking changes in SDK 17095, Paolo Bonzini, 2018/03/06
- [Qemu-devel] [PULL 29/34] Fix WHPX typo in 'mmio', Paolo Bonzini, 2018/03/06