The following commit has been merged into the x86/core branch of tip:
Commit-ID: c9a34c3f4ece192f6d804039fe6aac9618f0d236
Gitweb: https://git.kernel.org/tip/c9a34c3f4ece192f6d804039fe6aac9618f0d236
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 10 Nov 2021 11:01:16 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Sat, 11 Dec 2021 09:09:48 +01:00
x86/kvm: Remove .fixup usage
KVM instruction emulation has a gnarly hack where the .fixup does a
return, however there's already a ret right after the 10b label, so
mark that as 11 and have the exception clear %esi to remove the
.fixup.
Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211110101325.722157053@xxxxxxxxxxxxx
---
arch/x86/include/asm/extable_fixup_types.h | 1 +
arch/x86/kvm/emulate.c | 16 ++++------------
2 files changed, 5 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h
index a43b8c1..31ad42f 100644
--- a/arch/x86/include/asm/extable_fixup_types.h
+++ b/arch/x86/include/asm/extable_fixup_types.h
@@ -46,5 +46,6 @@
#define EX_TYPE_IMM_REG 17 /* reg := (long)imm */
#define EX_TYPE_EFAULT_REG (EX_TYPE_IMM_REG | EX_DATA_IMM(-EFAULT))
#define EX_TYPE_ZERO_REG (EX_TYPE_IMM_REG | EX_DATA_IMM(0))
+#define EX_TYPE_ONE_REG (EX_TYPE_IMM_REG | EX_DATA_IMM(1))
#endif
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b026350..1e19a4d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -315,7 +315,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
__FOP_FUNC(#name)
#define __FOP_RET(name) \
- ASM_RET \
+ "11: " ASM_RET \
".size " name ", .-" name "\n\t"
#define FOP_RET(name) \
@@ -344,7 +344,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
__FOP_RET(#op "_" #dst)
#define FOP1EEX(op, dst) \
- FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception)
+ FOP1E(op, dst) _ASM_EXTABLE_TYPE_REG(10b, 11b, EX_TYPE_ZERO_REG, %%esi)
#define FASTOP1(op) \
FOP_START(op) \
@@ -434,10 +434,6 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
#op " %al \n\t" \
__FOP_RET(#op)
-asm(".pushsection .fixup, \"ax\"\n"
- "kvm_fastop_exception: xor %esi, %esi; " ASM_RET
- ".popsection");
-
FOP_START(setcc)
FOP_SETCC(seto)
FOP_SETCC(setno)
@@ -473,12 +469,8 @@ FOP_END;
\
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 ); \
+ _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_ONE_REG, %[_fault]) \
+ : [_fault] "+r"(_fault) inoutclob ); \
\
_fault ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; \
})
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