[Xen-changelog] [xen-unstable] nestedsvm: fix VMEXIT emulation

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Christoph Egger <Christoph.Egger@xxxxxxx>
# Date 1350976467 -7200
# Node ID d642720e1ea996ce85203fc9718f64cf2cab0468
# Parent  a7503ce27d462056421c6d74737cee08ab4ae31e
nestedsvm: fix VMEXIT emulation

Values in regs can be newer than those in the shadow vmcb (e.g. due to
an instruction emulation right before). So use the values from regs.

Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
Committed-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r a7503ce27d46 -r d642720e1ea9 xen/arch/x86/hvm/svm/nestedsvm.c
--- a/xen/arch/x86/hvm/svm/nestedsvm.c  Tue Oct 23 09:13:27 2012 +0200
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c  Tue Oct 23 09:14:27 2012 +0200
@@ -995,7 +995,7 @@ nsvm_vmcb_guest_intercepts_trap(struct v
 }
 
 static int
-nsvm_vmcb_prepare4vmexit(struct vcpu *v)
+nsvm_vmcb_prepare4vmexit(struct vcpu *v, struct cpu_user_regs *regs)
 {
     struct nestedvcpu *nv = &vcpu_nestedhvm(v);
     struct nestedsvm *svm = &vcpu_nestedsvm(v);
@@ -1119,17 +1119,22 @@ nsvm_vmcb_prepare4vmexit(struct vcpu *v)
     ns_vmcb->_dr7 = n2vmcb->_dr7;
     ns_vmcb->_dr6 = n2vmcb->_dr6;
 
+    /* Restore registers from regs as those values
+     * can be newer than in n2vmcb (e.g. due to an
+     * instruction emulation right before).
+     */
+
     /* RFLAGS */
-    ns_vmcb->rflags = n2vmcb->rflags;
+    ns_vmcb->rflags = n2vmcb->rflags = regs->rflags;
 
     /* RIP */
-    ns_vmcb->rip = n2vmcb->rip;
+    ns_vmcb->rip = n2vmcb->rip = regs->rip;
 
     /* RSP */
-    ns_vmcb->rsp = n2vmcb->rsp;
+    ns_vmcb->rsp = n2vmcb->rsp = regs->rsp;
 
     /* RAX */
-    ns_vmcb->rax = n2vmcb->rax;
+    ns_vmcb->rax = n2vmcb->rax = regs->rax;
 
     /* Keep the l2 guest values of the fs, gs, ldtr, tr, kerngsbase,
      * star, lstar, cstar, sfmask, sysenter_cs, sysenter_esp,
@@ -1363,7 +1368,7 @@ nestedsvm_vmexit_n2n1(struct vcpu *v, st
     ASSERT(vcpu_nestedhvm(v).nv_vmswitch_in_progress);
     ASSERT(nestedhvm_vcpu_in_guestmode(v));
 
-    rc = nsvm_vmcb_prepare4vmexit(v);
+    rc = nsvm_vmcb_prepare4vmexit(v, regs);
     if (rc)
         ret = NESTEDHVM_VMEXIT_ERROR;
 

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