* [stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..."
@ 2013-09-04 16:44 Paul Gortmaker
2013-09-10 11:05 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Paul Gortmaker @ 2013-09-04 16:44 UTC (permalink / raw)
To: gregkh; +Cc: gleb, kvm, stable-commits
Hi Greg,
The 3.4.44+ cherry pick:
----------------
commit 5b5b30580218eae22609989546bac6e44d0eda6e
Author: Gleb Natapov <gleb@redhat.com>
Date: Wed Apr 24 13:38:36 2013 +0300
KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions
commit 660696d1d16a71e15549ce1bf74953be1592bcd3 upstream.
Source operand for one byte mov[zs]x is decoded incorrectly if it is in
high byte register. Fix that.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----------------
introduces the following:
arch/x86/kvm/emulate.c: In function ‘decode_operand’:
arch/x86/kvm/emulate.c:3974:4: warning: passing argument 1 of ‘decode_register’ makes integer from pointer without a cast [enabled by default]
arch/x86/kvm/emulate.c:789:14: note: expected ‘u8’ but argument is of type ‘struct x86_emulate_ctxt *’
arch/x86/kvm/emulate.c:3974:4: warning: passing argument 2 of ‘decode_register’ makes pointer from integer without a cast [enabled by default]
arch/x86/kvm/emulate.c:789:14: note: expected ‘long unsigned int *’ but argument is of type ‘u8’
Based on the severity of the warnings above, I'm reasonably sure there will
be some kind of runtime regressions due to this, but I stopped to investigate
the warnings as soon as I saw them, before any run time testing.
It happens because mainline v3.7-rc1~113^2~40 (dd856efafe60) does this:
-static void *decode_register(u8 modrm_reg, unsigned long *regs,
+static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
Since 660696d1d16a71e1 was only applied to stable 3.4, 3.8, and 3.9 -- and
the prerequisite above is in 3.7+, the issue should be limited to 3.4.44+
Thanks,
Paul.
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..."
2013-09-04 16:44 [stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..." Paul Gortmaker
@ 2013-09-10 11:05 ` Paolo Bonzini
2013-09-12 16:55 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2013-09-10 11:05 UTC (permalink / raw)
To: Paul Gortmaker; +Cc: gregkh, gleb, kvm, stable-commits
Il 04/09/2013 18:44, Paul Gortmaker ha scritto:
> Hi Greg,
>
> The 3.4.44+ cherry pick:
>
> ----------------
> commit 5b5b30580218eae22609989546bac6e44d0eda6e
> Author: Gleb Natapov <gleb@redhat.com>
> Date: Wed Apr 24 13:38:36 2013 +0300
>
> KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions
>
> commit 660696d1d16a71e15549ce1bf74953be1592bcd3 upstream.
>
> Source operand for one byte mov[zs]x is decoded incorrectly if it is in
> high byte register. Fix that.
>
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ----------------
>
> introduces the following:
>
> arch/x86/kvm/emulate.c: In function ‘decode_operand’:
> arch/x86/kvm/emulate.c:3974:4: warning: passing argument 1 of ‘decode_register’ makes integer from pointer without a cast [enabled by default]
> arch/x86/kvm/emulate.c:789:14: note: expected ‘u8’ but argument is of type ‘struct x86_emulate_ctxt *’
> arch/x86/kvm/emulate.c:3974:4: warning: passing argument 2 of ‘decode_register’ makes pointer from integer without a cast [enabled by default]
> arch/x86/kvm/emulate.c:789:14: note: expected ‘long unsigned int *’ but argument is of type ‘u8’
>
> Based on the severity of the warnings above, I'm reasonably sure there will
> be some kind of runtime regressions due to this, but I stopped to investigate
> the warnings as soon as I saw them, before any run time testing.
>
> It happens because mainline v3.7-rc1~113^2~40 (dd856efafe60) does this:
>
> -static void *decode_register(u8 modrm_reg, unsigned long *regs,
> +static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
>
> Since 660696d1d16a71e1 was only applied to stable 3.4, 3.8, and 3.9 -- and
> the prerequisite above is in 3.7+, the issue should be limited to 3.4.44+
Right, the fix is not important to have for 3.4 kernels.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..."
2013-09-10 11:05 ` Paolo Bonzini
@ 2013-09-12 16:55 ` Greg KH
0 siblings, 0 replies; 3+ messages in thread
From: Greg KH @ 2013-09-12 16:55 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Paul Gortmaker, gleb, kvm, stable-commits
On Tue, Sep 10, 2013 at 01:05:21PM +0200, Paolo Bonzini wrote:
> Il 04/09/2013 18:44, Paul Gortmaker ha scritto:
> > Hi Greg,
> >
> > The 3.4.44+ cherry pick:
> >
> > ----------------
> > commit 5b5b30580218eae22609989546bac6e44d0eda6e
> > Author: Gleb Natapov <gleb@redhat.com>
> > Date: Wed Apr 24 13:38:36 2013 +0300
> >
> > KVM: X86 emulator: fix source operand decoding for 8bit mov[zs]x instructions
> >
> > commit 660696d1d16a71e15549ce1bf74953be1592bcd3 upstream.
> >
> > Source operand for one byte mov[zs]x is decoded incorrectly if it is in
> > high byte register. Fix that.
> >
> > Signed-off-by: Gleb Natapov <gleb@redhat.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ----------------
> >
> > introduces the following:
> >
> > arch/x86/kvm/emulate.c: In function ‘decode_operand’:
> > arch/x86/kvm/emulate.c:3974:4: warning: passing argument 1 of ‘decode_register’ makes integer from pointer without a cast [enabled by default]
> > arch/x86/kvm/emulate.c:789:14: note: expected ‘u8’ but argument is of type ‘struct x86_emulate_ctxt *’
> > arch/x86/kvm/emulate.c:3974:4: warning: passing argument 2 of ‘decode_register’ makes pointer from integer without a cast [enabled by default]
> > arch/x86/kvm/emulate.c:789:14: note: expected ‘long unsigned int *’ but argument is of type ‘u8’
> >
> > Based on the severity of the warnings above, I'm reasonably sure there will
> > be some kind of runtime regressions due to this, but I stopped to investigate
> > the warnings as soon as I saw them, before any run time testing.
> >
> > It happens because mainline v3.7-rc1~113^2~40 (dd856efafe60) does this:
> >
> > -static void *decode_register(u8 modrm_reg, unsigned long *regs,
> > +static void *decode_register(struct x86_emulate_ctxt *ctxt, u8 modrm_reg,
> >
> > Since 660696d1d16a71e1 was only applied to stable 3.4, 3.8, and 3.9 -- and
> > the prerequisite above is in 3.7+, the issue should be limited to 3.4.44+
>
> Right, the fix is not important to have for 3.4 kernels.
Thanks for letting me know, I've now reverted it.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2013-09-12 16:56 UTC | newest]
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2013-09-04 16:44 [stable-3.4] possibly revert "KVM: X86 emulator: fix source operand decoding..." Paul Gortmaker
2013-09-10 11:05 ` Paolo Bonzini
2013-09-12 16:55 ` Greg KH
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