[Xen-changelog] [xen stable-4.7] Revert "x86/hvm: Perform a user instruction fetch for a FEP in userspace"

[patchbot@xxxxxxx]

commit 038aadd63752baf18b7cc9c7fbec0e5f3aa7c46a
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Sep 12 17:44:58 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Sep 12 17:44:58 2016 +0200

    Revert "x86/hvm: Perform a user instruction fetch for a FEP in userspace"
    
    This reverts commit 129099ba0c2407c32cd7f02011bdf98b8d7cfc0d,
    which uses uninitialized data in its current form.
---
 xen/arch/x86/hvm/hvm.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 39ffbf0..40665f5 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3890,8 +3890,6 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
     {
         struct vcpu *cur = current;
         struct segment_register cs;
-        uint32_t walk = (ctxt.seg_reg[x86_seg_ss].attr.fields.dpl == 3)
-            ? PFEC_user_mode : 0;
         unsigned long addr;
         char sig[5]; /* ud2; .ascii "xen" */
 
@@ -3902,7 +3900,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
                                          cs.attr.fields.l) ? 64 :
                                         cs.attr.fields.db ? 32 : 16, &addr) &&
              (hvm_fetch_from_guest_virt_nofault(sig, addr, sizeof(sig),
-                                                walk) == HVMCOPY_okay) &&
+                                                0) == HVMCOPY_okay) &&
              (memcmp(sig, "\xf\xbxen", sizeof(sig)) == 0) )
         {
             regs->eip += sizeof(sig);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.7

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