Patch "x86/retpoline/xen: Convert Xen hypercall indirect jumps" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

x86/retpoline/xen: Convert Xen hypercall indirect jumps

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Woodhouse <[email protected]>
Date: Thu, 11 Jan 2018 21:46:31 +0000
Subject: x86/retpoline/xen: Convert Xen hypercall indirect jumps

From: David Woodhouse <[email protected]>

commit ea08816d5b185ab3d09e95e393f265af54560350 upstream.

Convert indirect call in Xen hypercall to use non-speculative sequence, when CONFIG_RETPOLINE is enabled.

---
 arch/x86/include/asm/xen/hypercall.h |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -44,6 +44,7 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/smap.h>
+#include <asm/nospec-branch.h>
 
 #include <xen/interface/xen.h>
 #include <xen/interface/sched.h>

@@ -216,9 +217,9 @@ privcmd_call(unsigned call,
 	__HYPERCALL_5ARG(a1, a2, a3, a4, a5);
 
 	stac();
-	asm volatile("call *%[call]"
+	asm volatile(CALL_NOSPEC
 		     : __HYPERCALL_5PARAM
-		     : [call] "a" (&hypercall_page[call])
+		     : [thunk_target] "a" (&hypercall_page[call])
 		     : __HYPERCALL_CLOBBER5);
 	clac();
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch queue-4.9/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch queue-4.9/objtool-detect-jumps-to-retpoline-thunks.patch queue-4.9/x86-cpufeatures-add-x86_bug_spectre_v.patch queue-4.9/x86-alternatives-add-missing-n-at-end-of-alternative-inline-asm.patch queue-4.9/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch queue-4.9/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch queue-4.9/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch queue-4.9/x86-cpufeatures-add-x86_bug_cpu_insecure.patch queue-4.9/x86-cpufeatures-make-cpu-bugs-sticky.patch queue-4.9/x86-cpu-amd-make-lfence-a-serializing-instruction.patch queue-4.9/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch queue-4.9/objtool-allow-alternatives-to-be-ignored.patch queue-4.9/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch queue-4.9/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch queue-4.9/x86-cpu-factor-out-application-of-forced-cpu-caps.patch queue-4.9/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch queue-4.9/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch queue-4.9/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch queue-4.9/sysfs-cpu-add-vulnerability-folder.patch queue-4.9/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch queue-4.9/x86-pti-rename-bug_cpu_insecure-to-bug_cpu_meltdown.patch queue-4.9/x86-retpoline-remove-compile-time-warning.patch queue-4.9/x86-alternatives-fix-optimize_nops-checking.patch queue-4.9/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch queue-4.9/x86-retpoline-add-initial-retpoline-support.patch