4.4-stable review patch. If anyone has any objections, please let me know.
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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 */