From: Don Slutz <dslutz@verizon.com>
Date: Fri, 10 Jan 2014 21:57:00 +0000 (-0500)
Subject: xg_main: If XEN_DOMCTL_gdbsx_guestmemio fails then force error.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~5669
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=f91dc2000a86d0af00f52b527fd28df00070f9cb;p=xen.git

xg_main: If XEN_DOMCTL_gdbsx_guestmemio fails then force error.

Without this gdb does not report an error.

With this patch and using a 1G hvm domU:

(gdb) x/1xh 0x6ae9168b
0x6ae9168b:     Cannot access memory at address 0x6ae9168b

Drop output of iop->remain because it most likely will be zero.
This leads to a strange message:

ERROR: failed to read 0 bytes. errno:14 rc:-1

Add address to write error because it may be the only message
displayed.

Note: currently XEN_DOMCTL_gdbsx_guestmemio does not change 'iop' on
error and so iop->remain will be zero.

Signed-off-by: Don Slutz <dslutz@verizon.com>
Acked-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---

diff --git a/tools/debugger/gdbsx/xg/xg_main.c b/tools/debugger/gdbsx/xg/xg_main.c
index 3b2a2855b9..0fc3f820ad 100644
--- a/tools/debugger/gdbsx/xg/xg_main.c
+++ b/tools/debugger/gdbsx/xg/xg_main.c
@@ -787,8 +787,10 @@ xg_read_mem(uint64_t guestva, char *tobuf, int tobuf_len, uint64_t pgd3val)
     iop->gwr = 0;       /* not writing to guest */
 
     if ( (rc = _domctl_hcall(XEN_DOMCTL_gdbsx_guestmemio, tobuf, tobuf_len)) )
-        XGTRC("ERROR: failed to read %d bytes. errno:%d rc:%d\n",
-              iop->remain, errno, rc);
+    {
+        XGTRC("ERROR: failed to read bytes. errno:%d rc:%d\n", errno, rc);
+        return tobuf_len;
+    }
 
     for(i=0; i < XGMIN(8, tobuf_len); u.buf8[i]=tobuf[i], i++);
     XGTRC("X:remain:%d buf8:0x%llx\n", iop->remain, u.llbuf8);
@@ -818,8 +820,11 @@ xg_write_mem(uint64_t guestva, char *frombuf, int buflen, uint64_t pgd3val)
     iop->gwr = 1;       /* writing to guest */
 
     if ((rc=_domctl_hcall(XEN_DOMCTL_gdbsx_guestmemio, frombuf, buflen)))
-        XGERR("ERROR: failed to write %d bytes. errno:%d rc:%d\n", 
-              iop->remain, errno, rc);
+    {
+        XGERR("ERROR: failed to write bytes to %llx. errno:%d rc:%d\n",
+              guestva, errno, rc);
+        return buflen;
+    }
     return iop->remain;
 }