Re: [PATCH] KVM: Fix wrong KVM_GET_LAPIC

Avi Kivity
2008-08-20T07:10:59Z

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.