[Xen-changelog] [xen stable-4.6] x86/pv: Protect multicalls against Spectre v2 - Branch Target Injection

[patchbot@xxxxxxx]

commit a0db1f211f4970066d5544f7408d8cbdb3a302a0
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri May 18 13:26:15 2018 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 18 13:26:15 2018 +0200

    x86/pv: Protect multicalls against Spectre v2 - Branch Target Injection
    
    This is a missing adjustment in c/s 88602190f69 "x86: Support indirect 
thunks
    from assembly code".
    
    This is part of XSA-254.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/include/asm-x86/multicall.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/include/asm-x86/multicall.h b/xen/include/asm-x86/multicall.h
index 3cb0b6d9a0..415d7646b7 100644
--- a/xen/include/asm-x86/multicall.h
+++ b/xen/include/asm-x86/multicall.h
@@ -34,7 +34,7 @@ enum mc_disposition {
             "    movq  %c2+3*%c3(%0),%%rcx; "                \
             "    movq  %c2+4*%c3(%0),%%r8; "                 \
             "    movq  %c2+5*%c3(%0),%%r9; "                 \
-            "    callq *%%rax; "                             \
+            "    INDIRECT_CALL %%rax; "                      \
             "1:  movq  %%rax,%c4(%0)\n"                      \
             ".section .fixup,\"ax\"\n"                       \
             "2:  movq  %5,%%rax\n"                           \
@@ -67,7 +67,7 @@ enum mc_disposition {
             "    movl  %c2+3*%c3(%0),%%ecx; "                \
             "    movl  %c2+4*%c3(%0),%%r8d; "                \
             "    movl  %c2+5*%c3(%0),%%r9d; "                \
-            "    callq *%%rax; "                             \
+            "    INDIRECT_CALL %%rax; "                      \
             "1:  movl  %%eax,%c4(%0)\n"                      \
             ".section .fixup,\"ax\"\n"                       \
             "2:  movl  %5,%%eax\n"                           \
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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