Commit-ID: 1a29b5b7f347a1a9230c1e0af5b37e3e571588ab Gitweb: https://git.kernel.org/tip/1a29b5b7f347a1a9230c1e0af5b37e3e571588ab Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Thu, 25 Jan 2018 10:58:13 +0100 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Thu, 25 Jan 2018 11:30:07 +0100
KVM: x86: Make indirect calls in emulator speculation safe Replace the indirect calls with CALL_NOSPEC. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Reviewed-by: David Woodhouse <d...@amazon.co.uk> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Andi Kleen <a...@linux.intel.com> Cc: Ashok Raj <ashok....@intel.com> Cc: Greg KH <gre...@linuxfoundation.org> Cc: Jun Nakajima <jun.nakaj...@intel.com> Cc: David Woodhouse <dw...@infradead.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: r...@amazon.de Cc: Dave Hansen <dave.han...@intel.com> Cc: Asit Mallick <asit.k.mall...@intel.com> Cc: Andy Lutomirski <l...@kernel.org> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Jason Baron <jba...@akamai.com> Cc: Paolo Bonzini <pbonz...@redhat.com> Cc: Dan Williams <dan.j.willi...@intel.com> Cc: Arjan Van De Ven <arjan.van.de....@intel.com> Cc: Tim Chen <tim.c.c...@linux.intel.com> Link: https://lkml.kernel.org/r/20180125095843.595615...@infradead.org --- arch/x86/kvm/emulate.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index d90cdc7..453d8c9 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -25,6 +25,7 @@ #include <asm/kvm_emulate.h> #include <linux/stringify.h> #include <asm/debugreg.h> +#include <asm/nospec-branch.h> #include "x86.h" #include "tss.h" @@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsigned int condition, unsigned long flags) 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; } @@ -5305,9 +5306,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) 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), ASM_CALL_CONSTRAINT + [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT : "c"(ctxt->src2.val)); ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
