KVM: VMX: Make indirect call speculation safe

Replace indirect call 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/20180125095843.645776917@infradead.org

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d1e25db..924589c 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9064,14 +9064,14 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 #endif
                        "pushf\n\t"
                        __ASM_SIZE(push) " $%c[cs]\n\t"
-                       "call *%[entry]\n\t"
+                       CALL_NOSPEC
                        :
 #ifdef CONFIG_X86_64
                        [sp]"=&r"(tmp),
 #endif
                        ASM_CALL_CONSTRAINT
                        :
-                       [entry]"r"(entry),
+                       THUNK_TARGET(entry),
                        [ss]"i"(__KERNEL_DS),
                        [cs]"i"(__KERNEL_CS)
                        );