[PATCH v3 0/1] s390: ipl: fix physical-virtual confusion for diag308

[PATCH v3 0/1] s390: ipl: fix physical-virtual confusion for diag308

[Nico Boehr]

v3:
---
* u64 -> unsigned long (thanks Alexander)
* improve commit description a bit (thanks Alexander)

v2:
---
* add special handling for addr NULL (thanks Alexander)



Nico Boehr (1):
  s390: ipl: fix physical-virtual confusion for diag308

 arch/s390/kernel/ipl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.39.1

[PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Nico Boehr]

Diag 308 subcodes expect a physical address as their parameter.

This currently is not a bug, but in the future physical and virtual
addresses might differ.

Fix the confusion by doing a virtual-to-physical conversion in the
exported diag308() and leave the assembly wrapper __diag308() alone.

Note that several callers pass NULL as addr, so check for the case when
NULL is passed and pass 0 to hardware since virt_to_phys(0) might be
nonzero.

Suggested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 arch/s390/kernel/ipl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 5f0f5c86963a..afac9970ce42 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -176,11 +176,11 @@ static bool reipl_fcp_clear;
 static bool reipl_ccw_clear;
 static bool reipl_eckd_clear;
 
-static inline int __diag308(unsigned long subcode, void *addr)
+static inline int __diag308(unsigned long subcode, unsigned long addr)
 {
 	union register_pair r1;
 
-	r1.even = (unsigned long) addr;
+	r1.even = addr;
 	r1.odd	= 0;
 	asm volatile(
 		"	diag	%[r1],%[subcode],0x308\n"
@@ -195,7 +195,7 @@ static inline int __diag308(unsigned long subcode, void *addr)
 int diag308(unsigned long subcode, void *addr)
 {
 	diag_stat_inc(DIAG_STAT_X308);
-	return __diag308(subcode, addr);
+	return __diag308(subcode, addr ? virt_to_phys(addr) : 0);
 }
 EXPORT_SYMBOL_GPL(diag308);
 
-- 
2.39.1

Re: [PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Alexander Gordeev]

On Fri, Mar 10, 2023 at 02:34:11PM +0100, Nico Boehr wrote:
> Diag 308 subcodes expect a physical address as their parameter.
> 
> This currently is not a bug, but in the future physical and virtual
> addresses might differ.
> 
> Fix the confusion by doing a virtual-to-physical conversion in the
> exported diag308() and leave the assembly wrapper __diag308() alone.
> 
> Note that several callers pass NULL as addr, so check for the case when
> NULL is passed and pass 0 to hardware since virt_to_phys(0) might be
> nonzero.
> 
> Suggested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> ---
>  arch/s390/kernel/ipl.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
> index 5f0f5c86963a..afac9970ce42 100644
> --- a/arch/s390/kernel/ipl.c
> +++ b/arch/s390/kernel/ipl.c
> @@ -176,11 +176,11 @@ static bool reipl_fcp_clear;
>  static bool reipl_ccw_clear;
>  static bool reipl_eckd_clear;
>  
> -static inline int __diag308(unsigned long subcode, void *addr)
> +static inline int __diag308(unsigned long subcode, unsigned long addr)
>  {
>  	union register_pair r1;
>  
> -	r1.even = (unsigned long) addr;
> +	r1.even = addr;
>  	r1.odd	= 0;
>  	asm volatile(
>  		"	diag	%[r1],%[subcode],0x308\n"
> @@ -195,7 +195,7 @@ static inline int __diag308(unsigned long subcode, void *addr)
>  int diag308(unsigned long subcode, void *addr)
>  {
>  	diag_stat_inc(DIAG_STAT_X308);
> -	return __diag308(subcode, addr);
> +	return __diag308(subcode, addr ? virt_to_phys(addr) : 0);
>  }
>  EXPORT_SYMBOL_GPL(diag308);

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>

Re: [PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Alexander Gordeev]

Hi Nico,

Anything prevents this one from pushing?

Thanks!

Re: [PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Nico Boehr]

Quoting Alexander Gordeev (2023-03-31 08:48:37)
> Hi Nico,
> 
> Anything prevents this one from pushing?

No, can be pushed.

Re: [PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Alexander Gordeev]

On Fri, Mar 31, 2023 at 09:16:14AM +0200, Nico Boehr wrote:
> > Anything prevents this one from pushing?
> No, can be pushed.

Could you push it then, please?

Re: [PATCH v3 1/1] s390: ipl: fix physical-virtual confusion for diag308

[Nico Boehr]

Quoting Alexander Gordeev (2023-04-04 08:39:12)
> On Fri, Mar 31, 2023 at 09:16:14AM +0200, Nico Boehr wrote:
> > > Anything prevents this one from pushing?
> > No, can be pushed.
> 
> Could you push it then, please?

Done.