Patch "KVM: x86: Make indirect calls in emulator speculation safe" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    KVM: x86: Make indirect calls in emulator speculation safe

to the 4.4-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:
     kvm-x86-make-indirect-calls-in-emulator-speculation-safe.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Feb 23 17:23:58 CET 2018
From: Jack Wang <jinpu.wang@profitbricks.com>
Date: Fri, 23 Feb 2018 11:41:52 +0100
Subject: KVM: x86: Make indirect calls in emulator speculation safe
To: gregkh@linuxfoundation.org, stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, Andrea Arcangeli <aarcange@redhat.com>, Andi Kleen <ak@linux.intel.com>, Ashok Raj <ashok.raj@intel.com>, Jun Nakajima <jun.nakajima@intel.com>, David Woodhouse <dwmw2@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, rga@amazon.de, Dave Hansen <dave.hansen@intel.com>, Asit Mallick <asit.k.mallick@intel.com>, Andy Lutomirski <luto@kernel.org>, Josh Poimboeuf <jpoimboe@redhat.com>, Jason Baron <jbaron@akamai.com>, Paolo Bonzini <pbonzini@redhat.com>, Dan Williams <dan.j.williams@intel.com>, Arjan Van De Ven <arjan.van.de.ven@intel.com>, Tim Chen <tim.c.chen@linux.intel.com>, David Woodhouse <dwmw@amazon.co.uk>, Jack Wang <jinpu.wang@profitbricks.com>
Message-ID: <1519382538-15143-4-git-send-email-jinpu.wangl@profitbricks.com>

From: Peter Zijlstra <peterz@infradead.org>

(cherry picked from commit 1a29b5b7f347a1a9230c1e0af5b37e3e571588ab)

Replace the indirect calls with CALL_NOSPEC.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: rga@amazon.de
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Asit Mallick <asit.k.mallick@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Link: https://lkml.kernel.org/r/20180125095843.595615683@infradead.org
[dwmw2: Use ASM_CALL_CONSTRAINT like upstream, now we have it]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
[backport to 4.4]
Signed-off-by: Jack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/emulate.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -26,6 +26,7 @@
 #include <asm/kvm_emulate.h>
 #include <linux/stringify.h>
 #include <asm/debugreg.h>
+#include <asm/nospec-branch.h>
 
 #include "x86.h"
 #include "tss.h"
@@ -1000,8 +1001,8 @@ static u8 test_cc(unsigned int condition
 	void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
 
 	flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
-	asm("push %[flags]; popf; call *%[fastop]"
-	    : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
+	asm("push %[flags]; popf; " CALL_NOSPEC
+	    : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags));
 	return rc;
 }
 
@@ -5297,9 +5298,9 @@ static int fastop(struct x86_emulate_ctx
 	ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF;
 	if (!(ctxt->d & ByteOp))
 		fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
-	asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
+	asm("push %[flags]; popf; " CALL_NOSPEC "; pushf; pop %[flags]\n"
 	    : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
-	      [fastop]"+S"(fop)
+	      [thunk_target]"+S"(fop)
 	    : "c"(ctxt->src2.val));
 	ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
 	if (!fop) /* exception is returned in fop variable */


Patches currently in stable-queue which might be from jinpu.wang@profitbricks.com are

queue-4.4/x86-paravirt-remove-noreplace-paravirt-cmdline-option.patch
queue-4.4/documentation-document-array_index_nospec.patch
queue-4.4/kvm-x86-make-indirect-calls-in-emulator-speculation-safe.patch
queue-4.4/x86-nospec-fix-header-guards-names.patch
queue-4.4/x86-retpoline-avoid-retpolines-for-built-in-__init-functions.patch
queue-4.4/vfs-fdtable-prevent-bounds-check-bypass-via-speculative-execution.patch
queue-4.4/kvm-nvmx-invvpid-handling-improvements.patch
queue-4.4/x86-cpu-bugs-make-retpoline-module-warning-conditional.patch
queue-4.4/x86-spectre-check-config_retpoline-in-command-line-parser.patch
queue-4.4/x86-implement-array_index_mask_nospec.patch
queue-4.4/array_index_nospec-sanitize-speculative-array-de-references.patch
queue-4.4/kvm-vmx-make-indirect-call-speculation-safe.patch
queue-4.4/x86-spectre-fix-spelling-mistake-vunerable-vulnerable.patch
queue-4.4/kvm-nvmx-fix-kernel-panics-induced-by-illegal-invept-invvpid-types.patch
queue-4.4/module-retpoline-warn-about-missing-retpoline-in-module.patch
queue-4.4/x86-kvm-update-spectre-v1-mitigation.patch
queue-4.4/x86-get_user-use-pointer-masking-to-limit-speculation.patch
queue-4.4/x86-syscall-sanitize-syscall-table-de-references-under-speculation.patch
queue-4.4/kvm-nvmx-vmx_complete_nested_posted_interrupt-can-t-fail.patch
queue-4.4/x86-spectre-simplify-spectre_v2-command-line-parsing.patch
queue-4.4/x86-speculation-fix-typo-ibrs_att-which-should-be-ibrs_all.patch
queue-4.4/x86-spectre-report-get_user-mitigation-for-spectre_v1.patch
queue-4.4/x86-introduce-barrier_nospec.patch
queue-4.4/kvm-async_pf-fix-df-due-to-inject-page-not-present-and-page-ready-exceptions-simultaneously.patch
queue-4.4/kvm-vmx-clean-up-declaration-of-vpid-ept-invalidation-types.patch
queue-4.4/x86-bugs-drop-one-mitigation-from-dmesg.patch
queue-4.4/x86-retpoline-remove-the-esp-rsp-thunk.patch
queue-4.4/nl80211-sanitize-array-index-in-parse_txq_params.patch
queue-4.4/kvm-nvmx-kmap-can-t-fail.patch