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* [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails
@ 2019-08-15 16:20 Sean Christopherson
  2019-08-16 21:16 ` Jim Mattson
  2019-08-19 15:18 ` Paolo Bonzini
  0 siblings, 2 replies; 3+ messages in thread
From: Sean Christopherson @ 2019-08-15 16:20 UTC (permalink / raw)
  To: Paolo Bonzini, Radim Krčmář; +Cc: kvm, linux-kernel

Jump to the common error handling in x86_decode_insn() if
__do_insn_fetch_bytes() fails so that its error code is converted to the
appropriate return type.  Although the various helpers used by
x86_decode_insn() return X86EMUL_* values, x86_decode_insn() itself
returns EMULATION_FAILED or EMULATION_OK.

This doesn't cause a functional issue as the sole caller,
x86_emulate_instruction(), currently only cares about success vs.
failure, and success is indicated by '0' for both types
(X86EMUL_CONTINUE and EMULATION_OK).

Fixes: 285ca9e948fa ("KVM: emulate: speed up do_insn_fetch")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8e409ad448f9..6d2273e71020 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5126,7 +5126,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
 	else {
 		rc = __do_insn_fetch_bytes(ctxt, 1);
 		if (rc != X86EMUL_CONTINUE)
-			return rc;
+			goto done;
 	}
 
 	switch (mode) {
-- 
2.22.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails
  2019-08-15 16:20 [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails Sean Christopherson
@ 2019-08-16 21:16 ` Jim Mattson
  2019-08-19 15:18 ` Paolo Bonzini
  1 sibling, 0 replies; 3+ messages in thread
From: Jim Mattson @ 2019-08-16 21:16 UTC (permalink / raw)
  To: Sean Christopherson
  Cc: Paolo Bonzini, Radim Krčmář, kvm list, LKML

On Thu, Aug 15, 2019 at 9:20 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> Jump to the common error handling in x86_decode_insn() if
> __do_insn_fetch_bytes() fails so that its error code is converted to the
> appropriate return type.  Although the various helpers used by
> x86_decode_insn() return X86EMUL_* values, x86_decode_insn() itself
> returns EMULATION_FAILED or EMULATION_OK.
>
> This doesn't cause a functional issue as the sole caller,
> x86_emulate_instruction(), currently only cares about success vs.
> failure, and success is indicated by '0' for both types
> (X86EMUL_CONTINUE and EMULATION_OK).
>
> Fixes: 285ca9e948fa ("KVM: emulate: speed up do_insn_fetch")
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails
  2019-08-15 16:20 [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails Sean Christopherson
  2019-08-16 21:16 ` Jim Mattson
@ 2019-08-19 15:18 ` Paolo Bonzini
  1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2019-08-19 15:18 UTC (permalink / raw)
  To: Sean Christopherson, Radim Krčmář; +Cc: kvm, linux-kernel

On 15/08/19 18:20, Sean Christopherson wrote:
> Jump to the common error handling in x86_decode_insn() if
> __do_insn_fetch_bytes() fails so that its error code is converted to the
> appropriate return type.  Although the various helpers used by
> x86_decode_insn() return X86EMUL_* values, x86_decode_insn() itself
> returns EMULATION_FAILED or EMULATION_OK.
> 
> This doesn't cause a functional issue as the sole caller,
> x86_emulate_instruction(), currently only cares about success vs.
> failure, and success is indicated by '0' for both types
> (X86EMUL_CONTINUE and EMULATION_OK).
> 
> Fixes: 285ca9e948fa ("KVM: emulate: speed up do_insn_fetch")
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/emulate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 8e409ad448f9..6d2273e71020 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -5126,7 +5126,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
>  	else {
>  		rc = __do_insn_fetch_bytes(ctxt, 1);
>  		if (rc != X86EMUL_CONTINUE)
> -			return rc;
> +			goto done;
>  	}
>  
>  	switch (mode) {
> 

Queued, thanks.

Paolo

^ permalink raw reply	[flat|nested] 3+ messages in thread

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Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2019-08-15 16:20 [PATCH] KVM: x86: Fix x86_decode_insn() return when fetching insn bytes fails Sean Christopherson
2019-08-16 21:16 ` Jim Mattson
2019-08-19 15:18 ` Paolo Bonzini

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