[PATCH 1/2] Drivers: hv: Fix definition of hypercall input & output arg variables

[PATCH 1/2] Drivers: hv: Fix definition of hypercall input & output arg variables

[Michael Kelley]

The percpu variables hyperv_pcpu_input_arg and hyperv_pcpu_output_arg
have been incorrectly defined since their inception.  The __percpu
qualifier should be associated with the void * (i.e., a pointer), not
with the target of the pointer. This distinction makes no difference
to gcc and the generated code, but sparse correctly complains.  Fix
the definitions in the interest of general correctness in addition
to making sparse happy.

No functional change.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 drivers/hv/hv_common.c         | 4 ++--
 include/asm-generic/mshyperv.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 7be173a..7477e5a 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -44,10 +44,10 @@
 u32 hv_max_vp_index;
 EXPORT_SYMBOL_GPL(hv_max_vp_index);
 
-void  __percpu **hyperv_pcpu_input_arg;
+void * __percpu *hyperv_pcpu_input_arg;
 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
 
-void  __percpu **hyperv_pcpu_output_arg;
+void * __percpu *hyperv_pcpu_output_arg;
 EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
 
 /*
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 3e2248ac..95b7888 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -49,8 +49,8 @@ struct ms_hyperv_info {
 };
 extern struct ms_hyperv_info ms_hyperv;
 
-extern void  __percpu  **hyperv_pcpu_input_arg;
-extern void  __percpu  **hyperv_pcpu_output_arg;
+extern void * __percpu *hyperv_pcpu_input_arg;
+extern void * __percpu *hyperv_pcpu_output_arg;
 
 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
-- 
1.8.3.1

[PATCH 2/2] x86/hyperv: Fix definition of hv_ghcb_pg variable

[Michael Kelley]

The percpu variable hv_ghcb_pg is incorrectly defined.  The __percpu
qualifier should be associated with the union hv_ghcb * (i.e.,
a pointer), not with the target of the pointer. This distinction
makes no difference to gcc and the generated code, but sparse
correctly complains.  Fix the definition in the interest of
general correctness in addition to making sparse happy.

No functional change.

Fixes: 0cc4f6d9f0b9 ("x86/hyperv: Initialize GHCB page in Isolation VM")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
---
 arch/x86/hyperv/hv_init.c       | 2 +-
 arch/x86/include/asm/mshyperv.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 96eb7db..99afe77 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -36,7 +36,7 @@
 void *hv_hypercall_pg;
 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 
-union hv_ghcb __percpu **hv_ghcb_pg;
+union hv_ghcb * __percpu *hv_ghcb_pg;
 
 /* Storage to save the hypercall page temporarily for hibernation */
 static void *hv_hypercall_pg_saved;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index da3972f..498317d 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -30,7 +30,7 @@ typedef int (*hyperv_fill_flush_list_func)(
 
 extern u64 hv_current_partition_id;
 
-extern union hv_ghcb  __percpu **hv_ghcb_pg;
+extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
-- 
1.8.3.1

Re: [PATCH 1/2] Drivers: hv: Fix definition of hypercall input & output arg variables

[Wei Liu]

On Mon, Dec 27, 2021 at 07:31:54PM -0800, Michael Kelley wrote:
> The percpu variables hyperv_pcpu_input_arg and hyperv_pcpu_output_arg
> have been incorrectly defined since their inception.  The __percpu
> qualifier should be associated with the void * (i.e., a pointer), not
> with the target of the pointer. This distinction makes no difference
> to gcc and the generated code, but sparse correctly complains.  Fix
> the definitions in the interest of general correctness in addition
> to making sparse happy.
> 
> No functional change.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>

Good catch. I failed to interpret sparse's complaints.

Both patches queued to hyperv-next. Thanks.

> ---
>  drivers/hv/hv_common.c         | 4 ++--
>  include/asm-generic/mshyperv.h | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index 7be173a..7477e5a 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -44,10 +44,10 @@
>  u32 hv_max_vp_index;
>  EXPORT_SYMBOL_GPL(hv_max_vp_index);
>  
> -void  __percpu **hyperv_pcpu_input_arg;
> +void * __percpu *hyperv_pcpu_input_arg;
>  EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
>  
> -void  __percpu **hyperv_pcpu_output_arg;
> +void * __percpu *hyperv_pcpu_output_arg;
>  EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
>  
>  /*
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index 3e2248ac..95b7888 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -49,8 +49,8 @@ struct ms_hyperv_info {
>  };
>  extern struct ms_hyperv_info ms_hyperv;
>  
> -extern void  __percpu  **hyperv_pcpu_input_arg;
> -extern void  __percpu  **hyperv_pcpu_output_arg;
> +extern void * __percpu *hyperv_pcpu_input_arg;
> +extern void * __percpu *hyperv_pcpu_output_arg;
>  
>  extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
>  extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
> -- 
> 1.8.3.1
>