This is a note to let you know that I've just added the patch titled
KVM: x86: add asm_safe wrapper
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-add-asm_safe-wrapper.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From aabba3c6abd50b05b1fc2c6ec44244aa6bcda576 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@xxxxxxxxxx>
Date: Tue, 8 Nov 2016 20:54:18 +0100
Subject: KVM: x86: add asm_safe wrapper
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From: Radim Krčmář <rkrcmar@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
Patches currently in stable-queue which might be from rkrcmar@xxxxxxxxxx are
queue-4.4/kvm-x86-add-asm_safe-wrapper.patch
queue-4.4/kvm-eventfd-fix-null-deref-irqbypass-consumer.patch
queue-4.4/kvm-x86-add-align16-instruction-flag.patch
queue-4.4/kvm-x86-emulate-fxsave-and-fxrstor.patch
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