Re: [PATCH v1 2/5] xen/riscv: implement maddr_to_virt()

["Alejandro Vallejo" <alejandro.vallejo@xxxxxxxxx>]

On Wed Oct 16, 2024 at 10:15 AM BST, Oleksii Kurochko wrote:
> Implement the `maddr_to_virt()` function to convert a machine address
> to a virtual address. This function is specifically designed to be used
> only for the DIRECTMAP region, so a check has been added to ensure that
> the address does not exceed `DIRECTMAP_SIZE`.
>

nit: Worth mentioning this comes from the x86 side of things.

> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> ---
>  xen/arch/riscv/include/asm/mm.h | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/riscv/include/asm/mm.h b/xen/arch/riscv/include/asm/mm.h
> index ebb142502e..0396e66f47 100644
> --- a/xen/arch/riscv/include/asm/mm.h
> +++ b/xen/arch/riscv/include/asm/mm.h
> @@ -25,8 +25,12 @@
>  
>  static inline void *maddr_to_virt(paddr_t ma)
>  {
> -    BUG_ON("unimplemented");
> -    return NULL;
> +    /* Offset in the direct map, accounting for pdx compression */
> +    unsigned long va_offset = maddr_to_directmapoff(ma);
> +
> +    ASSERT(va_offset < DIRECTMAP_SIZE);
> +
> +    return (void *)(DIRECTMAP_VIRT_START + va_offset);
>  }
>  
>  /*