[Xen-devel] [PATCH v3] xen/x86: Identify which vcpu's CR4 is being badly modified

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

When the toolstack is setting vcpu state on behalf of a migrating guest, the
domain/vcpu reference from gdprintk() identifies the toolstack, not the
affected domain.

After this change, the error looks more like:

  (XEN) d0 attempted to change d6v0's CR4 flags 00002660 -> 01876000

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>

---
v3: Send correct patch.
v2: gdprintk -> printk, drop current's vcpu reference.
---
 xen/arch/x86/domain.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index b48f2dc..796b775 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -651,9 +651,9 @@ unsigned long pv_guest_cr4_fixup(const struct vcpu *v, 
unsigned long guest_cr4)
         hv_cr4_mask &= ~X86_CR4_OSXSAVE;
 
     if ( (guest_cr4 & hv_cr4_mask) != (hv_cr4 & hv_cr4_mask) )
-        gdprintk(XENLOG_WARNING,
-                 "Attempt to change CR4 flags %08lx -> %08lx\n",
-                 hv_cr4, guest_cr4);
+        printk(XENLOG_G_WARNING
+               "d%d attempted to change %pv's CR4 flags %08lx -> %08lx\n",
+               current->domain->domain_id, v, hv_cr4, guest_cr4);
 
     return (hv_cr4 & hv_cr4_mask) | (guest_cr4 & ~hv_cr4_mask);
 }
-- 
1.7.10.4


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