Re: [Xen-devel] [PATCH v4 06/10] xen/arm: mm: Use PAGE_HYPERVISOR_* instead of MT_* when calling set_fixmap

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 9 Oct 2017, Julien Grall wrote:
> At the moment, PAGE_HYPERVISOR_* and MT_* have exactly the same value.
> In a follow-up patch the former will be extended to carry more
> information.
> 
> It looks like the caller of set_fixmap are mixing the both. Stay
> consistent and only use PAGE_HYPERVISOR_*. This is also match the
> behavior of create_xen_entries and would potentially allow to share some
> part in the future.
> 
> Also rename the parameter 'attributes' to 'flags' so it is clearer what
> is the interface.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v4:
>         - Patch added.
> ---
>  xen/arch/arm/kernel.c             | 2 +-
>  xen/arch/arm/mm.c                 | 4 ++--
>  xen/arch/arm/platforms/vexpress.c | 3 ++-
>  xen/drivers/video/arm_hdlcd.c     | 2 +-
>  4 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
> index a12baa86e7..c2755a9ab9 100644
> --- a/xen/arch/arm/kernel.c
> +++ b/xen/arch/arm/kernel.c
> @@ -54,7 +54,7 @@ void copy_from_paddr(void *dst, paddr_t paddr, unsigned 
> long len)
>          s = paddr & (PAGE_SIZE-1);
>          l = min(PAGE_SIZE - s, len);
>  
> -        set_fixmap(FIXMAP_MISC, maddr_to_mfn(paddr), MT_NORMAL_NC);
> +        set_fixmap(FIXMAP_MISC, maddr_to_mfn(paddr), PAGE_HYPERVISOR_WC);
>          memcpy(dst, src + s, l);
>          clean_dcache_va_range(dst, l);
>  
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 39bade63f5..70a03015ec 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -329,9 +329,9 @@ static inline lpae_t mfn_to_xen_entry(mfn_t mfn, unsigned 
> attr)
>  }
>  
>  /* Map a 4k page in a fixmap entry */
> -void set_fixmap(unsigned map, mfn_t mfn, unsigned attributes)
> +void set_fixmap(unsigned map, mfn_t mfn, unsigned int flags)
>  {
> -    lpae_t pte = mfn_to_xen_entry(mfn, attributes);
> +    lpae_t pte = mfn_to_xen_entry(mfn, flags);
>      pte.pt.table = 1; /* 4k mappings always have this bit set */
>      pte.pt.xn = 1;
>      write_pte(xen_fixmap + third_table_offset(FIXMAP_ADDR(map)), pte);
> diff --git a/xen/arch/arm/platforms/vexpress.c 
> b/xen/arch/arm/platforms/vexpress.c
> index df2c4b5bec..39b6bcc70e 100644
> --- a/xen/arch/arm/platforms/vexpress.c
> +++ b/xen/arch/arm/platforms/vexpress.c
> @@ -65,7 +65,8 @@ int vexpress_syscfg(int write, int function, int device, 
> uint32_t *data)
>      uint32_t *syscfg = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
>      int ret = -1;
>  
> -    set_fixmap(FIXMAP_MISC, maddr_to_mfn(V2M_SYS_MMIO_BASE), 
> MT_DEVICE_nGnRE);
> +    set_fixmap(FIXMAP_MISC, maddr_to_mfn(V2M_SYS_MMIO_BASE),
> +               PAGE_HYPERVISOR_NOCACHE);
>  
>      if ( syscfg[V2M_SYS_CFGCTRL/4] & V2M_SYS_CFG_START )
>          goto out;
> diff --git a/xen/drivers/video/arm_hdlcd.c b/xen/drivers/video/arm_hdlcd.c
> index 1175399dbc..e1174b223f 100644
> --- a/xen/drivers/video/arm_hdlcd.c
> +++ b/xen/drivers/video/arm_hdlcd.c
> @@ -227,7 +227,7 @@ void __init video_init(void)
>      /* uses FIXMAP_MISC */
>      set_pixclock(videomode->pixclock);
>  
> -    set_fixmap(FIXMAP_MISC, maddr_to_mfn(hdlcd_start), MT_DEVICE_nGnRE);
> +    set_fixmap(FIXMAP_MISC, maddr_to_mfn(hdlcd_start), 
> PAGE_HYPERVISOR_NOCACHE);
>      HDLCD[HDLCD_COMMAND] = 0;
>  
>      HDLCD[HDLCD_LINELENGTH] = videomode->xres * bytes_per_pixel;
> -- 
> 2.11.0
> 

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