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[Qemu-devel] [PATCH] exec: Fix MAP_RAM for cached access
From: |
Eric Auger |
Subject: |
[Qemu-devel] [PATCH] exec: Fix MAP_RAM for cached access |
Date: |
Tue, 12 Jun 2018 21:05:25 +0200 |
When an IOMMUMemoryRegion is in front of a virtio device,
address_space_cache_init does not set cache->ptr as the memory
region is not RAM. However when the device performs an access,
we end up in glue() which performs the translation and then uses
MAP_RAM. This latter uses the unset ptr and returns a wrong value
which leads to a SIGSEV in address_space_lduw_internal_cached_slow,
for instance. Let's test whether the cache->ptr is set, and in
the negative use the old macro definition. This fixes the
use cases featuring vIOMMU (Intel and ARM SMMU) which lead to
a SIGSEV.
Fixes: 48564041a73a (exec: reintroduce MemoryRegion caching)
Signed-off-by: Eric Auger <address@hidden>
---
I am not sure whether it doesn't break any targeted optimization
but at least it removes the SIGSEV.
Signed-off-by: Eric Auger <address@hidden>
---
exec.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index f6645ed..46fbd25 100644
--- a/exec.c
+++ b/exec.c
@@ -3800,7 +3800,9 @@ address_space_write_cached_slow(MemoryRegionCache *cache,
hwaddr addr,
#define SUFFIX _cached_slow
#define TRANSLATE(...) address_space_translate_cached(cache,
__VA_ARGS__)
#define IS_DIRECT(mr, is_write) memory_access_is_direct(mr, is_write)
-#define MAP_RAM(mr, ofs) (cache->ptr + (ofs - cache->xlat))
+#define MAP_RAM(mr, ofs) (cache->ptr ? \
+ (cache->ptr + (ofs - cache->xlat)) : \
+ qemu_map_ram_ptr((mr)->ram_block, ofs))
#define INVALIDATE(mr, ofs, len) invalidate_and_set_dirty(mr, ofs, len)
#define RCU_READ_LOCK() ((void)0)
#define RCU_READ_UNLOCK() ((void)0)
--
2.5.5
- [Qemu-devel] [PATCH] exec: Fix MAP_RAM for cached access,
Eric Auger <=