Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-20 Thread Paul Mackerras
On Mon, Aug 10, 2015 at 11:27:31AM -0400, Nicholas Krause wrote:
> This fixes the wrapper functions kvm_umap_hva_hv and the function
> kvm_unmap_hav_range_hv to return the return value of the function
> kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
> call internally rather then always making the caller of these
> wrapper functions think they always run successfully by returning
> the value of zero directly.

In fact these functions do always run successfully, and there is no
bug fixed here (see below).

I don't object to the change per se, since it reduces the code size
very slightly, but the commit message and headline needs to be
reworded to avoid giving the impression that this fixes something.

>  int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
>  {
> - kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
> - return 0;
> + return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
>  }
>  
>  int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned 
> long end)
>  {
> - kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
> - return 0;
> + return kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);

kvm_handle_hva and kvm_handle_hva_range call the handler function
(kvm_unmap_rmapp in this case) one or more times, and return the
logical OR of the return values from the handler.  Since
kvm_unmap_rmapp always returns 0, the return value from
kvm_handle_hva{,_range} will always be 0 here.

Paul.
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Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-20 Thread Paul Mackerras
On Mon, Aug 10, 2015 at 11:27:31AM -0400, Nicholas Krause wrote:
 This fixes the wrapper functions kvm_umap_hva_hv and the function
 kvm_unmap_hav_range_hv to return the return value of the function
 kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
 call internally rather then always making the caller of these
 wrapper functions think they always run successfully by returning
 the value of zero directly.

In fact these functions do always run successfully, and there is no
bug fixed here (see below).

I don't object to the change per se, since it reduces the code size
very slightly, but the commit message and headline needs to be
reworded to avoid giving the impression that this fixes something.

  int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
  {
 - kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
 - return 0;
 + return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
  }
  
  int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned 
 long end)
  {
 - kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
 - return 0;
 + return kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);

kvm_handle_hva and kvm_handle_hva_range call the handler function
(kvm_unmap_rmapp in this case) one or more times, and return the
logical OR of the return values from the handler.  Since
kvm_unmap_rmapp always returns 0, the return value from
kvm_handle_hva{,_range} will always be 0 here.

Paul.
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Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-13 Thread Michael Ellerman
On Wed, 2015-08-12 at 21:06 +0200, Alexander Graf wrote:
> 
> On 10.08.15 17:27, Nicholas Krause wrote:
> > This fixes the wrapper functions kvm_umap_hva_hv and the function
> > kvm_unmap_hav_range_hv to return the return value of the function
> > kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
> > call internally rather then always making the caller of these
> > wrapper functions think they always run successfully by returning
> > the value of zero directly.
> > 
> > Signed-off-by: Nicholas Krause 
> 
> Paul, could you please take on this one?

Paul's away for a while can you take it directly?

cheers


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Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-13 Thread Michael Ellerman
On Wed, 2015-08-12 at 21:06 +0200, Alexander Graf wrote:
 
 On 10.08.15 17:27, Nicholas Krause wrote:
  This fixes the wrapper functions kvm_umap_hva_hv and the function
  kvm_unmap_hav_range_hv to return the return value of the function
  kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
  call internally rather then always making the caller of these
  wrapper functions think they always run successfully by returning
  the value of zero directly.
  
  Signed-off-by: Nicholas Krause xerofo...@gmail.com
 
 Paul, could you please take on this one?

Paul's away for a while can you take it directly?

cheers


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Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-12 Thread Alexander Graf


On 10.08.15 17:27, Nicholas Krause wrote:
> This fixes the wrapper functions kvm_umap_hva_hv and the function
> kvm_unmap_hav_range_hv to return the return value of the function
> kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
> call internally rather then always making the caller of these
> wrapper functions think they always run successfully by returning
> the value of zero directly.
> 
> Signed-off-by: Nicholas Krause 

Paul, could you please take on this one?

Thanks,

Alex

> ---
>  arch/powerpc/kvm/book3s_64_mmu_hv.c | 6 ++
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c 
> b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index dab68b7..0905c8f 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -774,14 +774,12 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned 
> long *rmapp,
>  
>  int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
>  {
> - kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
> - return 0;
> + return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
>  }
>  
>  int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned 
> long end)
>  {
> - kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
> - return 0;
> + return kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
>  }
>  
>  void kvmppc_core_flush_memslot_hv(struct kvm *kvm,
> 
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Re: [PATCH] kvm:powerpc:Fix return statements for wrapper functions in the file book3s_64_mmu_hv.c

2015-08-12 Thread Alexander Graf


On 10.08.15 17:27, Nicholas Krause wrote:
 This fixes the wrapper functions kvm_umap_hva_hv and the function
 kvm_unmap_hav_range_hv to return the return value of the function
 kvm_handle_hva or kvm_handle_hva_range that they are wrapped to
 call internally rather then always making the caller of these
 wrapper functions think they always run successfully by returning
 the value of zero directly.
 
 Signed-off-by: Nicholas Krause xerofo...@gmail.com

Paul, could you please take on this one?

Thanks,

Alex

 ---
  arch/powerpc/kvm/book3s_64_mmu_hv.c | 6 ++
  1 file changed, 2 insertions(+), 4 deletions(-)
 
 diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c 
 b/arch/powerpc/kvm/book3s_64_mmu_hv.c
 index dab68b7..0905c8f 100644
 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
 +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
 @@ -774,14 +774,12 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned 
 long *rmapp,
  
  int kvm_unmap_hva_hv(struct kvm *kvm, unsigned long hva)
  {
 - kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
 - return 0;
 + return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
  }
  
  int kvm_unmap_hva_range_hv(struct kvm *kvm, unsigned long start, unsigned 
 long end)
  {
 - kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
 - return 0;
 + return kvm_handle_hva_range(kvm, start, end, kvm_unmap_rmapp);
  }
  
  void kvmppc_core_flush_memslot_hv(struct kvm *kvm,
 
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