From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34366) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSobq-0006YH-E8 for qemu-devel@nongnu.org; Tue, 12 Jun 2018 15:05:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSobn-0001KH-3t for qemu-devel@nongnu.org; Tue, 12 Jun 2018 15:05:38 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45892 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fSobn-0001Jf-0F for qemu-devel@nongnu.org; Tue, 12 Jun 2018 15:05:35 -0400 From: Eric Auger Date: Tue, 12 Jun 2018 21:05:25 +0200 Message-Id: <1528830325-5501-1-git-send-email-eric.auger@redhat.com> Subject: [Qemu-devel] [PATCH] exec: Fix MAP_RAM for cached access List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, pbonzini@redhat.com Cc: peterx@redhat.com 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 --- I am not sure whether it doesn't break any targeted optimization but at least it removes the SIGSEV. Signed-off-by: Eric Auger --- 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