[Xen-devel] RE: xenpm fail

[Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>]

Thanks for this...

On Mon, 2010-11-01 at 10:49 +0000, Zhang, Yang Z wrote:
[...]
> xc__hypercall_bounce_pre bounced 32 bytes from user buf 0x7fffffffe720 into 
> hcall buf 0x607004
> xc__hypercall_bounce_pre bounced 32 bytes from user buf 0x7fffffffe728 into 
> hcall buf 0x609004
> xc__hypercall_bounce_pre bounced 136 bytes from user buf 0x7fffffffe610 into 
> hcall buf 0x60b004
> xc__hypercall_bounce_post bounced 136 bytes back from hcall buf 0x60b004 into 
> user buf 0x7fffffffe610
> xc__hypercall_bounce_post bounced 32 bytes back from hcall buf 0x609004 into 
> user buf 0x7fffffffe728
> xc__hypercall_bounce_post bounced 32 bytes back from hcall buf 0x607004 into 
> user buf 0x7fffffffe720

This is the xc_pm_get_cxstat call, we can see it bounce max_cx(=4) *
sizeof(uint64_t)==32 bytes for both cxpt->triggers and cxpt->residencies
as well as 136 bytes for struct xensysctl.

However the ubuf values for triggers and residencies are suspicious,
they are only 8 bytes different, IOW they apparently overlap.

Can you try this patch which fixes a stupid thinko.

diff -r c3d7d2729410 tools/libxc/xc_pm.c
--- a/tools/libxc/xc_pm.c       Mon Nov 01 11:12:51 2010 +0000
+++ b/tools/libxc/xc_pm.c       Mon Nov 01 11:19:53 2010 +0000
@@ -124,8 +124,8 @@ int xc_pm_get_cxstat(xc_interface *xch, 
 int xc_pm_get_cxstat(xc_interface *xch, int cpuid, struct xc_cx_stat *cxpt)
 {
     DECLARE_SYSCTL;
-    DECLARE_NAMED_HYPERCALL_BOUNCE(triggers, &cxpt->triggers, 0, 
XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
-    DECLARE_NAMED_HYPERCALL_BOUNCE(residencies, &cxpt->residencies, 0, 
XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
+    DECLARE_NAMED_HYPERCALL_BOUNCE(triggers, cxpt->triggers, 0, 
XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
+    DECLARE_NAMED_HYPERCALL_BOUNCE(residencies, cxpt->residencies, 0, 
XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
     int max_cx, ret;
 
     if( !cxpt || !(cxpt->triggers) || !(cxpt->residencies) )



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