| From aabba3c6abd50b05b1fc2c6ec44244aa6bcda576 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com> |
| Date: Tue, 8 Nov 2016 20:54:18 +0100 |
| Subject: KVM: x86: add asm_safe wrapper |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Radim Krčmář <rkrcmar@redhat.com> |
| |
| commit aabba3c6abd50b05b1fc2c6ec44244aa6bcda576 upstream. |
| |
| Move the existing exception handling for inline assembly into a macro |
| and switch its return values to X86EMUL type. |
| |
| Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kvm/emulate.c | 34 +++++++++++++++++++++++----------- |
| 1 file changed, 23 insertions(+), 11 deletions(-) |
| |
| --- a/arch/x86/kvm/emulate.c |
| +++ b/arch/x86/kvm/emulate.c |
| @@ -435,6 +435,26 @@ FOP_END; |
| FOP_START(salc) "pushf; sbb %al, %al; popf \n\t" FOP_RET |
| FOP_END; |
| |
| +/* |
| + * XXX: inoutclob user must know where the argument is being expanded. |
| + * Relying on CC_HAVE_ASM_GOTO would allow us to remove _fault. |
| + */ |
| +#define asm_safe(insn, inoutclob...) \ |
| +({ \ |
| + int _fault = 0; \ |
| + \ |
| + asm volatile("1:" insn "\n" \ |
| + "2:\n" \ |
| + ".pushsection .fixup, \"ax\"\n" \ |
| + "3: movl $1, %[_fault]\n" \ |
| + " jmp 2b\n" \ |
| + ".popsection\n" \ |
| + _ASM_EXTABLE(1b, 3b) \ |
| + : [_fault] "+qm"(_fault) inoutclob ); \ |
| + \ |
| + _fault ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; \ |
| +}) |
| + |
| static int emulator_check_intercept(struct x86_emulate_ctxt *ctxt, |
| enum x86_intercept intercept, |
| enum x86_intercept_stage stage) |
| @@ -5086,21 +5106,13 @@ static bool string_insn_completed(struct |
| |
| static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt) |
| { |
| - bool fault = false; |
| + int rc; |
| |
| ctxt->ops->get_fpu(ctxt); |
| - asm volatile("1: fwait \n\t" |
| - "2: \n\t" |
| - ".pushsection .fixup,\"ax\" \n\t" |
| - "3: \n\t" |
| - "movb $1, %[fault] \n\t" |
| - "jmp 2b \n\t" |
| - ".popsection \n\t" |
| - _ASM_EXTABLE(1b, 3b) |
| - : [fault]"+qm"(fault)); |
| + rc = asm_safe("fwait"); |
| ctxt->ops->put_fpu(ctxt); |
| |
| - if (unlikely(fault)) |
| + if (unlikely(rc != X86EMUL_CONTINUE)) |
| return emulate_exception(ctxt, MF_VECTOR, 0, false); |
| |
| return X86EMUL_CONTINUE; |
