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

Christian Borntraeger
2022-11-07T11:22:09Z

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;