[Xen-changelog] [xen stable-4.6] x86/mmuext: tighten TLB flush address checks

[patchbot@xxxxxxx]

commit b9c4de31fdd817e404f158357e675edfe857d366
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Feb 17 16:36:47 2016 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 17 16:36:47 2016 +0100

    x86/mmuext: tighten TLB flush address checks
    
    Addresses passed by PV guests should be subjected to __addr_ok(),
    avoiding undue TLB flushes.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 828e114f7cdd9910483783ab0563b178325e579a
    master date: 2016-01-21 16:09:22 +0100
---
 xen/arch/x86/mm.c            | 13 +++++++------
 xen/include/asm-x86/paging.h |  4 +++-
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 1800f33..17644aa 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -3281,8 +3281,9 @@ long do_mmuext_op(
         case MMUEXT_INVLPG_LOCAL:
             if ( unlikely(d != pg_owner) )
                 rc = -EPERM;
-            else if ( !paging_mode_enabled(d) ||
-                      paging_invlpg(curr, op.arg1.linear_addr) != 0 )
+            else if ( !paging_mode_enabled(d)
+                      ? __addr_ok(op.arg1.linear_addr)
+                      : paging_invlpg(curr, op.arg1.linear_addr) )
                 flush_tlb_one_local(op.arg1.linear_addr);
             break;
 
@@ -3303,7 +3304,7 @@ long do_mmuext_op(
 
             if ( op.cmd == MMUEXT_TLB_FLUSH_MULTI )
                 flush_tlb_mask(&pmask);
-            else
+            else if ( __addr_ok(op.arg1.linear_addr) )
                 flush_tlb_one_mask(&pmask, op.arg1.linear_addr);
             break;
         }
@@ -3316,10 +3317,10 @@ long do_mmuext_op(
             break;
     
         case MMUEXT_INVLPG_ALL:
-            if ( likely(d == pg_owner) )
-                flush_tlb_one_mask(d->domain_dirty_cpumask, 
op.arg1.linear_addr);
-            else
+            if ( unlikely(d != pg_owner) )
                 rc = -EPERM;
+            else if ( __addr_ok(op.arg1.linear_addr) )
+                flush_tlb_one_mask(d->domain_dirty_cpumask, 
op.arg1.linear_addr);
             break;
 
         case MMUEXT_FLUSH_CACHE:
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index 6215f57..c412953 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -245,7 +245,9 @@ paging_fault(unsigned long va, struct cpu_user_regs *regs)
  * or 0 if it's safe not to do so. */
 static inline int paging_invlpg(struct vcpu *v, unsigned long va)
 {
-    return is_canonical_address(va) && paging_get_hostmode(v)->invlpg(v, va);
+    return (paging_mode_external(v->domain) ? is_canonical_address(va)
+                                            : __addr_ok(va)) &&
+           paging_get_hostmode(v)->invlpg(v, va);
 }
 
 /* Translate a guest virtual address to the frame number that the
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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