[PATCH v1] s390/mm: fix virtual-physical address confusion for swiotlb

[PATCH v1] s390/mm: fix virtual-physical address confusion for swiotlb

[Nico Boehr]

swiotlb passes virtual addresses to set_memory_encrypted() and
set_memory_decrypted(), but uv_remove_shared() and uv_set_shared()
expect physical addresses. This currently works, because virtual
and physical addresses are the same.

Add virt_to_phys() to resolve the virtual-physical confusion.

Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
 arch/s390/mm/init.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 97d66a3e60fb..8b652654064e 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -146,7 +146,7 @@ int set_memory_encrypted(unsigned long addr, int numpages)
 
 	/* make specified pages unshared, (swiotlb, dma_free) */
 	for (i = 0; i < numpages; ++i) {
-		uv_remove_shared(addr);
+		uv_remove_shared(virt_to_phys((void *)addr));
 		addr += PAGE_SIZE;
 	}
 	return 0;
@@ -157,7 +157,7 @@ int set_memory_decrypted(unsigned long addr, int numpages)
 	int i;
 	/* make specified pages shared (swiotlb, dma_alloca) */
 	for (i = 0; i < numpages; ++i) {
-		uv_set_shared(addr);
+		uv_set_shared(virt_to_phys((void *)addr));
 		addr += PAGE_SIZE;
 	}
 	return 0;
-- 
2.37.3

Re: [PATCH v1] s390/mm: fix virtual-physical address confusion for swiotlb

[Christian Borntraeger]

Am 07.11.22 um 11:58 schrieb Nico Boehr:
> swiotlb passes virtual addresses to set_memory_encrypted() and
> set_memory_decrypted(), but uv_remove_shared() and uv_set_shared()
> expect physical addresses. This currently works, because virtual
> and physical addresses are the same.
> 
> Add virt_to_phys() to resolve the virtual-physical confusion.
> 
> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
> Signed-off-by: Nico Boehr <nrb@linux.ibm.com>

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>

I am asking myself if we should rename addr to vaddr to make this more obvious.
(Other users of these functions do use vaddr as well).

> ---
>   arch/s390/mm/init.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index 97d66a3e60fb..8b652654064e 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -146,7 +146,7 @@ int set_memory_encrypted(unsigned long addr, int numpages)
>   
>   	/* make specified pages unshared, (swiotlb, dma_free) */
>   	for (i = 0; i < numpages; ++i) {
> -		uv_remove_shared(addr);
> +		uv_remove_shared(virt_to_phys((void *)addr));
>   		addr += PAGE_SIZE;
>   	}
>   	return 0;
> @@ -157,7 +157,7 @@ int set_memory_decrypted(unsigned long addr, int numpages)
>   	int i;
>   	/* make specified pages shared (swiotlb, dma_alloca) */
>   	for (i = 0; i < numpages; ++i) {
> -		uv_set_shared(addr);
> +		uv_set_shared(virt_to_phys((void *)addr));
>   		addr += PAGE_SIZE;
>   	}
>   	return 0;

Re: [PATCH v1] s390/mm: fix virtual-physical address confusion for swiotlb

[Nico Boehr]

Quoting Christian Borntraeger (2022-11-07 12:21:58)
> Am 07.11.22 um 11:58 schrieb Nico Boehr:
> > swiotlb passes virtual addresses to set_memory_encrypted() and
> > set_memory_decrypted(), but uv_remove_shared() and uv_set_shared()
> > expect physical addresses. This currently works, because virtual
> > and physical addresses are the same.
> > 
> > Add virt_to_phys() to resolve the virtual-physical confusion.
> > 
> > Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
> > Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
> 
> Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> 
> I am asking myself if we should rename addr to vaddr to make this more obvious.
> (Other users of these functions do use vaddr as well).

I had this at some point, but then changed it back because at the time I
thought we don't own the prototype.

However, looking at it again, it looks like that's wrong and we do own
it in arch/s390/include/asm/mem_encrypt.h.

So I think it's a good suggestion and I will pick it up for v2.