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Message-Id: <20161108195419.4607-4-rkrcmar@redhat.com>
Date: Tue, 8 Nov 2016 20:54:18 +0100
From: Radim Krčmář <rkrcmar@...hat.com>
To: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>, Bandan Das <bsd@...hat.com>,
Nadav Amit <nadav.amit@...il.com>
Subject: [PATCH v3 3/4] KVM: x86: add asm_safe wrapper
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@...hat.com>
---
v2: new
---
arch/x86/kvm/emulate.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 14624d6bf112..6af3cac6ec89 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -448,6 +448,26 @@ 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)
@@ -5087,21 +5107,13 @@ static bool string_insn_completed(struct x86_emulate_ctxt *ctxt)
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;
--
2.10.2
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