qemu-cvs-alsa_mmap

Hack to prevent ALSA from using mmap() interface to simplify emulation.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Ulrich Hecht <uli@suse.de>

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index a249f0c..34a5615 100644 (file)
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -366,6 +366,9 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
     }
 }
 
+#define SNDRV_PCM_MMAP_OFFSET_STATUS  0x80000000
+#define SNDRV_PCM_MMAP_OFFSET_CONTROL 0x81000000
+
 /* NOTE: all the constants are the HOST ones */
 abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
                      int flags, int fd, abi_ulong offset)
@@ -400,6 +403,17 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
     }
 #endif
 
+    /* Alsa tries to communcate with the kernel via mmap. This usually
+     * is a good idea when user- and kernelspace are running on the
+     * same architecture but does not work out when not. To make alsa
+     * not to use mmap, we can just have it fail on the mmap calls that
+     * would initiate this.
+     */
+    if(offset == SNDRV_PCM_MMAP_OFFSET_STATUS || offset == SNDRV_PCM_MMAP_OFFSET_CONTROL) {
+       errno = EINVAL;
+       return -1;
+    }
+
     if (offset & ~TARGET_PAGE_MASK) {
         errno = EINVAL;
         goto fail;