[Xen-changelog] [xen stable-4.3] x86/PV: don't commit debug register values early in arch_set_info_guest()

[patchbot@xxxxxxx]

commit f5f4f5c5f55e3a5a701ff23bc8bf5a520f034770
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Jan 10 11:04:18 2014 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jan 10 11:04:18 2014 +0100

    x86/PV: don't commit debug register values early in arch_set_info_guest()
    
    They're being taken care of later (via set_debugreg()), and temporarily
    copying them into struct vcpu means that bad values may end up getting
    loaded during context switch if the vCPU is already running and the
    function errors out between the premature and real commit step, leading
    to the same issue that XSA-12 dealt with.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Release-acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
    master commit: 398c39b6c18d0b55acfc88f5ee75b3a793e6eeec
    master date: 2013-12-11 10:33:19 +0100
---
 xen/arch/x86/domain.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 146fb9f..f01c7e3 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -720,13 +720,14 @@ int arch_set_info_guest(
             XLAT_trap_info(v->arch.pv_vcpu.trap_ctxt + i,
                            c.cmp->trap_ctxt + i);
     }
-    for ( i = 0; i < ARRAY_SIZE(v->arch.debugreg); ++i )
-        v->arch.debugreg[i] = c(debugreg[i]);
 
     v->arch.user_regs.eflags |= 2;
 
     if ( is_hvm_vcpu(v) )
     {
+        for ( i = 0; i < ARRAY_SIZE(v->arch.debugreg); ++i )
+            v->arch.debugreg[i] = c(debugreg[i]);
+
         hvm_set_info_guest(v);
         goto out;
     }
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.3

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