Re: [PATCH] KVM: Fix EPT identity IOCTL on 32pae

[Jan Kiszka <jan.kiszka@siemens.com>]

Sheng Yang wrote:
> Copy u64 from guest result in chaos.

Not doing so, while the ABI as been defined as u64, will surely result
in chaos as well - just different one. I'm recalling the problems Alex
recently ran into on big-endian PowerPC and sizeof(userland_long) !=
sizeof(kernel_long).

> 
> Also fix a mistake of still using old macro rather than new variable().

Two patches then?

> 
> Signed-off-by: Sheng Yang <sheng@linux.intel.com>
> ---
>  arch/x86/kvm/vmx.c |    2 +-
>  arch/x86/kvm/x86.c |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 7931c72..c5aaa1b 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2199,7 +2199,7 @@ static int alloc_identity_pagetable(struct kvm *kvm)
>  		goto out;
>  
>  	kvm->arch.ept_identity_pagetable = gfn_to_page(kvm,
> -			VMX_EPT_IDENTITY_PAGETABLE_ADDR >> PAGE_SHIFT);
> +			kvm->arch.ept_identity_map_addr >> PAGE_SHIFT);
>  out:
>  	up_write(&kvm->slots_lock);
>  	return r;
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 2539e9a..977b705 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2178,7 +2178,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
>  			goto out;
>  		break;
>  	case KVM_SET_IDENTITY_MAP_ADDR: {
> -		u64 ident_addr;
> +		unsigned long ident_addr;
>  
>  		r = -EFAULT;
>  		if (copy_from_user(&ident_addr, argp, sizeof ident_addr))

I don't know what as to be fixed here, but you must stick to the ABI.
Maybe you just want to convert u64 -> ulong afterwards?

Jan

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