Re: [PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n
Avi Kivity <[EMAIL PROTECTED]> wrote:
> A "g" constraint may place a local variable in an %rsp-relative memory
> operand.
> but if your assembly changes %rsp, the operand points to the wrong location.
>
> An "r" constraint fixes that.
>
> Thanks to Ingo Molnar for neatly bisecting the problem.
>
> Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
>
> Index: linux-2.6/drivers/kvm/vmx.c
> ===
> --- linux-2.6.orig/drivers/kvm/vmx.c
> +++ linux-2.6/drivers/kvm/vmx.c
> @@ -1825,7 +1825,7 @@ again:
> #endif
>"setbe %0 \n\t"
>"popf \n\t"
> - : "=g" (fail)
> + : "=r" (fail)
> : "r"(vcpu->launched), "d"((unsigned long)HOST_RSP),
>"c"(vcpu),
>[rax]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),
We need the following fix for 2.6.20.
[KVM] vmx: Fix register constraint in launch code
Both "=r" and "=g" breaks my build on i386:
$ make
CC [M] drivers/kvm/vmx.o
{standard input}: Assembler messages:
{standard input}:3318: Error: bad register name `%sil'
make[1]: *** [drivers/kvm/vmx.o] Error 1
make: *** [_module_drivers/kvm] Error 2
The reason is that setbe requires an 8-bit register but "=r" does not
constrain the target register to be one that has an 8-bit version on
i386.
According to
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10153
the correct constraint is "=q".
Signed-off-by: Herbert Xu <[EMAIL PROTECTED]>
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index ce219e3..0aa2659 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1824,7 +1824,7 @@ again:
#endif
"setbe %0 \n\t"
"popf \n\t"
- : "=g" (fail)
+ : "=q" (fail)
: "r"(vcpu->launched), "d"((unsigned long)HOST_RSP),
"c"(vcpu),
[rax]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),
-
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Re: [PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n
Avi Kivity [EMAIL PROTECTED] wrote:
A g constraint may place a local variable in an %rsp-relative memory
operand.
but if your assembly changes %rsp, the operand points to the wrong location.
An r constraint fixes that.
Thanks to Ingo Molnar for neatly bisecting the problem.
Signed-off-by: Avi Kivity [EMAIL PROTECTED]
Index: linux-2.6/drivers/kvm/vmx.c
===
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -1825,7 +1825,7 @@ again:
#endif
setbe %0 \n\t
popf \n\t
- : =g (fail)
+ : =r (fail)
: r(vcpu-launched), d((unsigned long)HOST_RSP),
c(vcpu),
[rax]i(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),
We need the following fix for 2.6.20.
[KVM] vmx: Fix register constraint in launch code
Both =r and =g breaks my build on i386:
$ make
CC [M] drivers/kvm/vmx.o
{standard input}: Assembler messages:
{standard input}:3318: Error: bad register name `%sil'
make[1]: *** [drivers/kvm/vmx.o] Error 1
make: *** [_module_drivers/kvm] Error 2
The reason is that setbe requires an 8-bit register but =r does not
constrain the target register to be one that has an 8-bit version on
i386.
According to
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10153
the correct constraint is =q.
Signed-off-by: Herbert Xu [EMAIL PROTECTED]
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmVHI~} [EMAIL PROTECTED]
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index ce219e3..0aa2659 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1824,7 +1824,7 @@ again:
#endif
setbe %0 \n\t
popf \n\t
- : =g (fail)
+ : =q (fail)
: r(vcpu-launched), d((unsigned long)HOST_RSP),
c(vcpu),
[rax]i(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),
-
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n
A "g" constraint may place a local variable in an %rsp-relative memory operand. but if your assembly changes %rsp, the operand points to the wrong location. An "r" constraint fixes that. Thanks to Ingo Molnar for neatly bisecting the problem. Signed-off-by: Avi Kivity <[EMAIL PROTECTED]> Index: linux-2.6/drivers/kvm/vmx.c === --- linux-2.6.orig/drivers/kvm/vmx.c +++ linux-2.6/drivers/kvm/vmx.c @@ -1825,7 +1825,7 @@ again: #endif "setbe %0 \n\t" "popf \n\t" - : "=g" (fail) + : "=r" (fail) : "r"(vcpu->launched), "d"((unsigned long)HOST_RSP), "c"(vcpu), [rax]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])), - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n
A g constraint may place a local variable in an %rsp-relative memory operand. but if your assembly changes %rsp, the operand points to the wrong location. An r constraint fixes that. Thanks to Ingo Molnar for neatly bisecting the problem. Signed-off-by: Avi Kivity [EMAIL PROTECTED] Index: linux-2.6/drivers/kvm/vmx.c === --- linux-2.6.orig/drivers/kvm/vmx.c +++ linux-2.6/drivers/kvm/vmx.c @@ -1825,7 +1825,7 @@ again: #endif setbe %0 \n\t popf \n\t - : =g (fail) + : =r (fail) : r(vcpu-launched), d((unsigned long)HOST_RSP), c(vcpu), [rax]i(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])), - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
