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Re: [PATCH v2 1/7] xen/acpi: Rework acpi_os_map_memory() and acpi_os_unmap_memory()



On Fri, 23 Oct 2020, Julien Grall wrote:
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> The functions acpi_os_{un,}map_memory() are meant to be arch-agnostic
> while the __acpi_os_{un,}map_memory() are meant to be arch-specific.
> 
> Currently, the former are still containing x86 specific code.
> 
> To avoid this rather strange split, the generic helpers are reworked so
> they are arch-agnostic. This requires the introduction of a new helper
> __acpi_os_unmap_memory() that will undo any mapping done by
> __acpi_os_map_memory().
> 
> Currently, the arch-helper for unmap is basically a no-op so it only
> returns whether the mapping was arch specific. But this will change
> in the future.
> 
> Note that the x86 version of acpi_os_map_memory() was already able to
> able the 1MB region. Hence why there is no addition of new code.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> Reviewed-by: Rahul Singh <rahul.singh@xxxxxxx>
> Tested-by: Rahul Singh <rahul.singh@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v2:
>         - Constify ptr in __acpi_unmap_table()
>         - Coding style fixes
>         - Fix build on arm64
>         - Use PAGE_OFFSET() rather than open-coding it
>         - Add Rahul's tested-by and reviewed-by
> ---
>  xen/arch/arm/acpi/lib.c | 12 ++++++++++++
>  xen/arch/x86/acpi/lib.c | 18 ++++++++++++++++++
>  xen/drivers/acpi/osl.c  | 34 ++++++++++++++++++----------------
>  xen/include/xen/acpi.h  |  1 +
>  4 files changed, 49 insertions(+), 16 deletions(-)
> 
> diff --git a/xen/arch/arm/acpi/lib.c b/xen/arch/arm/acpi/lib.c
> index 4fc6e17322c1..fcc186b03399 100644
> --- a/xen/arch/arm/acpi/lib.c
> +++ b/xen/arch/arm/acpi/lib.c
> @@ -30,6 +30,10 @@ char *__acpi_map_table(paddr_t phys, unsigned long size)
>      unsigned long base, offset, mapped_size;
>      int idx;
>  
> +    /* No arch specific implementation after early boot */
> +    if ( system_state >= SYS_STATE_boot )
> +        return NULL;
> +
>      offset = phys & (PAGE_SIZE - 1);
>      mapped_size = PAGE_SIZE - offset;
>      set_fixmap(FIXMAP_ACPI_BEGIN, maddr_to_mfn(phys), PAGE_HYPERVISOR);
> @@ -49,6 +53,14 @@ char *__acpi_map_table(paddr_t phys, unsigned long size)
>      return ((char *) base + offset);
>  }
>  
> +bool __acpi_unmap_table(const void *ptr, unsigned long size)
> +{
> +    vaddr_t vaddr = (vaddr_t)ptr;
> +
> +    return ((vaddr >= FIXMAP_ADDR(FIXMAP_ACPI_BEGIN)) &&
> +            (vaddr < (FIXMAP_ADDR(FIXMAP_ACPI_END) + PAGE_SIZE)));
> +}
> +
>  /* True to indicate PSCI 0.2+ is implemented */
>  bool __init acpi_psci_present(void)
>  {
> diff --git a/xen/arch/x86/acpi/lib.c b/xen/arch/x86/acpi/lib.c
> index 265b9ad81905..a22414a05c13 100644
> --- a/xen/arch/x86/acpi/lib.c
> +++ b/xen/arch/x86/acpi/lib.c
> @@ -46,6 +46,10 @@ char *__acpi_map_table(paddr_t phys, unsigned long size)
>       if ((phys + size) <= (1 * 1024 * 1024))
>               return __va(phys);
>  
> +     /* No further arch specific implementation after early boot */
> +     if (system_state >= SYS_STATE_boot)
> +             return NULL;
> +
>       offset = phys & (PAGE_SIZE - 1);
>       mapped_size = PAGE_SIZE - offset;
>       set_fixmap(FIX_ACPI_END, phys);
> @@ -66,6 +70,20 @@ char *__acpi_map_table(paddr_t phys, unsigned long size)
>       return ((char *) base + offset);
>  }
>  
> +bool __acpi_unmap_table(const void *ptr, unsigned long size)
> +{
> +     unsigned long vaddr = (unsigned long)ptr;
> +
> +     if ((vaddr >= DIRECTMAP_VIRT_START) &&
> +         (vaddr < DIRECTMAP_VIRT_END)) {
> +             ASSERT(!((__pa(ptr) + size - 1) >> 20));
> +             return true;
> +     }
> +
> +     return ((vaddr >= __fix_to_virt(FIX_ACPI_END)) &&
> +             (vaddr < (__fix_to_virt(FIX_ACPI_BEGIN) + PAGE_SIZE)));
> +}
> +
>  unsigned int acpi_get_processor_id(unsigned int cpu)
>  {
>       unsigned int acpiid, apicid;
> diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c
> index 4c8bb7839eda..389505f78666 100644
> --- a/xen/drivers/acpi/osl.c
> +++ b/xen/drivers/acpi/osl.c
> @@ -92,27 +92,29 @@ acpi_physical_address __init 
> acpi_os_get_root_pointer(void)
>  void __iomem *
>  acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
>  {
> -     if (system_state >= SYS_STATE_boot) {
> -             mfn_t mfn = _mfn(PFN_DOWN(phys));
> -             unsigned int offs = phys & (PAGE_SIZE - 1);
> -
> -             /* The low first Mb is always mapped on x86. */
> -             if (IS_ENABLED(CONFIG_X86) && !((phys + size - 1) >> 20))
> -                     return __va(phys);
> -             return __vmap(&mfn, PFN_UP(offs + size), 1, 1,
> -                           ACPI_MAP_MEM_ATTR, VMAP_DEFAULT) + offs;
> -     }
> -     return __acpi_map_table(phys, size);
> +     void *ptr;
> +     mfn_t mfn = _mfn(PFN_DOWN(phys));
> +     unsigned int offs = PAGE_OFFSET(phys);
> +
> +     /* Try the arch specific implementation first */
> +     ptr = __acpi_map_table(phys, size);
> +     if (ptr)
> +             return ptr;
> +
> +     /* No common implementation for early boot map */
> +     if (unlikely(system_state < SYS_STATE_boot))
> +             return NULL;
> +
> +     ptr = __vmap(&mfn, PFN_UP(offs + size), 1, 1,
> +                  ACPI_MAP_MEM_ATTR, VMAP_DEFAULT);
> +
> +     return !ptr ? NULL : (ptr + offs);
>  }
>  
>  void acpi_os_unmap_memory(void __iomem * virt, acpi_size size)
>  {
> -     if (IS_ENABLED(CONFIG_X86) &&
> -         (unsigned long)virt >= DIRECTMAP_VIRT_START &&
> -         (unsigned long)virt < DIRECTMAP_VIRT_END) {
> -             ASSERT(!((__pa(virt) + size - 1) >> 20));
> +     if (__acpi_unmap_table(virt, size))
>               return;
> -     }
>  
>       if (system_state >= SYS_STATE_boot)
>               vunmap((void *)((unsigned long)virt & PAGE_MASK));
> diff --git a/xen/include/xen/acpi.h b/xen/include/xen/acpi.h
> index c945ab05c864..21d5e9feb5ae 100644
> --- a/xen/include/xen/acpi.h
> +++ b/xen/include/xen/acpi.h
> @@ -68,6 +68,7 @@ typedef int (*acpi_table_entry_handler) (struct 
> acpi_subtable_header *header, co
>  
>  unsigned int acpi_get_processor_id (unsigned int cpu);
>  char * __acpi_map_table (paddr_t phys_addr, unsigned long size);
> +bool __acpi_unmap_table(const void *ptr, unsigned long size);
>  int acpi_boot_init (void);
>  int acpi_boot_table_init (void);
>  int acpi_numa_init (void);
> -- 
> 2.17.1
> 



 


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