[Qemu-devel] [PATCH] Fix xen pci passthrough

[Wei Wang]

Hi, I find a passthrough issue in qemu when pci device has multiple mmio 
regions. In this case, the last few bytes of qmp response string are trimmed 
and then passthru fails with following output.

*** glibc detected *** xl: realloc(): invalid pointer: 0x0000000002163f90 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x74c06)[0x7f62970e4c06]
/lib64/libc.so.6(+0x77d25)[0x7f62970e7d25]
/lib/libxenlight.so.2.0(+0x28d02)[0x7f6297a78d02]
/lib/libxenlight.so.2.0(+0x2eccf)[0x7f6297a7eccf]
/lib/libxenlight.so.2.0(+0x2f2f6)[0x7f6297a7f2f6]
/lib/libxenlight.so.2.0(+0x2fe18)[0x7f6297a7fe18]
/lib/libxenlight.so.2.0(+0x20027)[0x7f6297a70027]
/lib/libxenlight.so.2.0(+0x212a6)[0x7f6297a712a6]
/lib/libxenlight.so.2.0(+0x19e82)[0x7f6297a69e82]
/lib/libxenlight.so.2.0(+0x1c288)[0x7f6297a6c288]
/lib/libxenlight.so.2.0(+0x1c2a8)[0x7f6297a6c2a8]
/lib/libxenlight.so.2.0(+0x2657e)[0x7f6297a7657e]
/lib/libxenlight.so.2.0(+0x34076)[0x7f6297a84076]
/lib/libxenlight.so.2.0(libxl__fork_selfpipe_woken+0x92)[0x7f6297a84394]
/lib/libxenlight.so.2.0(+0x3254a)[0x7f6297a8254a]
/lib/libxenlight.so.2.0(+0x3276d)[0x7f6297a8276d]
/lib/libxenlight.so.2.0(+0x33944)[0x7f6297a83944]
/lib/libxenlight.so.2.0(+0x1c0a8)[0x7f6297a6c0a8]
/lib/libxenlight.so.2.0(libxl_domain_create_new+0x14)[0x7f6297a6c14f]
xl[0x40c1f2]
xl[0x40fc94]
xl[0x406c21]
/lib64/libc.so.6(__libc_start_main+0xed)[0x7f629709123d]
xl[0x406439]

Attached patch can fix this issue. 

Thanks,
Wei

Signed-off-by: Wei Wang <address@hidden>

---
 monitor.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/monitor.c b/monitor.c
index f6107ba..9f30f5f 100644
--- a/monitor.c
+++ b/monitor.c
@@ -165,7 +165,7 @@ struct Monitor {
     int reset_seen;
     int flags;
     int suspend_cnt;
-    uint8_t outbuf[1024];
+    uint8_t outbuf[2048];
     int outbuf_index;
     ReadLineState *rs;
     MonitorControl *mc;
-- 
1.7.4