[PATCH] kvm/vmx: fix the return value of handle_vmcall()

[PATCH] kvm/vmx: fix the return value of handle_vmcall()

[Jesse Larrew]

The return value of kvm_emulate_hypercall() is intended to inform callers
whether or not we need to exit to userspace. However, handle_vmcall()
currently ignores the return value.

This patch simply propogates the return value from kvm_emulate_hypercall()
to callers so that it can be acted upon appropriately.

Signed-off-by: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
---
 arch/x86/kvm/vmx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f858159..8b37f5f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4682,8 +4682,7 @@ static int handle_halt(struct kvm_vcpu *vcpu)
 static int handle_vmcall(struct kvm_vcpu *vcpu)
 {
 	skip_emulated_instruction(vcpu);
-	kvm_emulate_hypercall(vcpu);
-	return 1;
+	return kvm_emulate_hypercall(vcpu);
 }
 
 static int handle_invd(struct kvm_vcpu *vcpu)
-- 
1.7.11.7

Jesse Larrew
Software Engineer, KVM Team
IBM Linux Technology Center
Phone: (512) 973-2052 (T/L: 363-2052)
jlarrew@linux.vnet.ibm.com

Re: [PATCH] kvm/vmx: fix the return value of handle_vmcall()

[Gleb Natapov]

On Mon, Dec 10, 2012 at 03:28:13PM -0600, Jesse Larrew wrote:
> 
> The return value of kvm_emulate_hypercall() is intended to inform callers
> whether or not we need to exit to userspace. However, handle_vmcall()
> currently ignores the return value.
> 
No, it it not. KVM does not handle vmcalls in userspace.

> This patch simply propogates the return value from kvm_emulate_hypercall()
> to callers so that it can be acted upon appropriately.
> 
> Signed-off-by: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
> ---
>  arch/x86/kvm/vmx.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index f858159..8b37f5f 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -4682,8 +4682,7 @@ static int handle_halt(struct kvm_vcpu *vcpu)
>  static int handle_vmcall(struct kvm_vcpu *vcpu)
>  {
>  	skip_emulated_instruction(vcpu);
> -	kvm_emulate_hypercall(vcpu);
> -	return 1;
> +	return kvm_emulate_hypercall(vcpu);
>  }
>  
>  static int handle_invd(struct kvm_vcpu *vcpu)
> -- 
> 1.7.11.7
> 
> Jesse Larrew
> Software Engineer, KVM Team
> IBM Linux Technology Center
> Phone: (512) 973-2052 (T/L: 363-2052)
> jlarrew@linux.vnet.ibm.com
> 
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--
			Gleb.