Re: [PATCH 03/22] acpi: vmap pages in acpi_os_alloc_memory

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 16 Dec 2022, Julien Grall wrote:
> From: Hongyan Xia <hongyxia@xxxxxxxxxx>
> 
> Also, introduce a wrapper around vmap that maps a contiguous range for
> boot allocations. Unfortunately, the new helper cannot be a static inline
> because the dependences are a mess. We would need to re-include
> asm/page.h (was removed in aa4b9d1ee653 "include: don't use asm/page.h
> from common headers") and it doesn't look to be enough anymore
> because bits from asm/cpufeature.h is used in the definition of PAGE_NX.
> 
> Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx>
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

I saw Jan's comments and I agree with them but I also wanted to track
that I reviewed this patch and looks OK:

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ----
> 
>     Changes since Hongyan's version:
>         * Rename vmap_boot_pages() to vmap_contig_pages()
>         * Move the new helper in vmap.c to avoid compilation issue
>         * Don't use __pa() to translate the virtual address
> ---
>  xen/common/vmap.c      |  5 +++++
>  xen/drivers/acpi/osl.c | 13 +++++++++++--
>  xen/include/xen/vmap.h |  2 ++
>  3 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/common/vmap.c b/xen/common/vmap.c
> index 1340c7c6faf6..78f051a67682 100644
> --- a/xen/common/vmap.c
> +++ b/xen/common/vmap.c
> @@ -244,6 +244,11 @@ void *vmap(const mfn_t *mfn, unsigned int nr)
>      return __vmap(mfn, 1, nr, 1, PAGE_HYPERVISOR, VMAP_DEFAULT);
>  }
>  
> +void *vmap_contig_pages(mfn_t mfn, unsigned int nr_pages)
> +{
> +    return __vmap(&mfn, nr_pages, 1, 1, PAGE_HYPERVISOR, VMAP_DEFAULT);
> +}
> +
>  void vunmap(const void *va)
>  {
>      unsigned long addr = (unsigned long)va;
> diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c
> index 389505f78666..44a9719b0dcf 100644
> --- a/xen/drivers/acpi/osl.c
> +++ b/xen/drivers/acpi/osl.c
> @@ -221,7 +221,11 @@ void *__init acpi_os_alloc_memory(size_t sz)
>       void *ptr;
>  
>       if (system_state == SYS_STATE_early_boot)
> -             return mfn_to_virt(mfn_x(alloc_boot_pages(PFN_UP(sz), 1)));
> +     {
> +             mfn_t mfn = alloc_boot_pages(PFN_UP(sz), 1);
> +
> +             return vmap_contig_pages(mfn, PFN_UP(sz));
> +     }
>  
>       ptr = xmalloc_bytes(sz);
>       ASSERT(!ptr || is_xmalloc_memory(ptr));
> @@ -246,5 +250,10 @@ void __init acpi_os_free_memory(void *ptr)
>       if (is_xmalloc_memory(ptr))
>               xfree(ptr);
>       else if (ptr && system_state == SYS_STATE_early_boot)
> -             init_boot_pages(__pa(ptr), __pa(ptr) + PAGE_SIZE);
> +     {
> +             paddr_t addr = mfn_to_maddr(vmap_to_mfn(ptr));
> +
> +             vunmap(ptr);
> +             init_boot_pages(addr, addr + PAGE_SIZE);
> +     }
>  }
> diff --git a/xen/include/xen/vmap.h b/xen/include/xen/vmap.h
> index b0f7632e8985..3c06c7c3ba30 100644
> --- a/xen/include/xen/vmap.h
> +++ b/xen/include/xen/vmap.h
> @@ -23,6 +23,8 @@ void *vmalloc_xen(size_t size);
>  void *vzalloc(size_t size);
>  void vfree(void *va);
>  
> +void *vmap_contig_pages(mfn_t mfn, unsigned int nr_pages);
> +
>  void __iomem *ioremap(paddr_t, size_t);
>  
>  static inline void iounmap(void __iomem *va)
> -- 
> 2.38.1
>