Re: [PATCH] KVM: Fix wrong KVM_GET_LAPIC

[Avi Kivity <avi@qumranet.com>]

Amit Shah wrote:
> * On Monday 18 Aug 2008 08:45:40 Yang, Sheng wrote:
>   
>> From a8ca7dd8f5fe0125e7b7d0a21f5caddacd754911 Mon Sep 17 00:00:00 2001
>> From: Sheng Yang <sheng.yang@intel.com>
>> Date: Mon, 18 Aug 2008 11:04:22 +0800
>> Subject: [PATCH] KVM: Fix wrong KVM_GET_LAPIC
>>
>> Which caused migration fail in recent commits.
>>
>> Signed-off-by: Sheng Yang <sheng.yang@intel.com>
>> ---
>>  arch/x86/kvm/x86.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index ee005a6..4a03375 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -1555,7 +1555,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>>  		if (r)
>>  			goto out;
>>  		r = -EFAULT;
>> -		if (copy_to_user(argp, &lapic, sizeof lapic))
>> +		if (copy_to_user(argp, lapic, sizeof(struct kvm_lapic_state)))
>>     
>
> We're passing the structure instead of the pointer 

'lapic' is now a pointer to a struct kvm_lapic_state.

> and this leads to build 
> break with the tip on kvm.git.
>
>   

Builds for me.  Please double check.

> What's the point of this change anyway?
>   

Fixing save/restore, which got broken by the stack usage reduction patches.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.