Re: [Xen-devel] [PATCH] Xen: EFI: Parse DT parameters for Xen specific UEFI

[Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>]

On 6 May 2016 at 02:32, Shannon Zhao <zhaoshenglong@xxxxxxxxxx> wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> Add a new function to parse DT parameters for Xen specific UEFI just
> like the way for normal UEFI. Then it could reuse the existing codes.
>
> If Xen supports EFI, initialize runtime services.
>
> CC: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> Drop using of EFI_PARAVIRT. Discussion can be found from [1].
> [1] https://lkml.org/lkml/2016/4/29/8
> ---
>  arch/arm/include/asm/efi.h         |  2 +
>  arch/arm/xen/enlighten.c           | 16 ++++++++
>  arch/arm64/include/asm/efi.h       |  2 +
>  drivers/firmware/efi/arm-runtime.c | 70 +++++++++++++++++++++++---------
>  drivers/firmware/efi/efi.c         | 81 
> ++++++++++++++++++++++++++++++--------
>  5 files changed, 137 insertions(+), 34 deletions(-)
>
> diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h
> index e0eea72..5ba4343 100644
> --- a/arch/arm/include/asm/efi.h
> +++ b/arch/arm/include/asm/efi.h
> @@ -52,9 +52,11 @@ static inline void efi_set_pgd(struct mm_struct *mm)
>
>  void efi_virtmap_load(void);
>  void efi_virtmap_unload(void);
> +int xen_arm_enable_runtime_services(void);
>
>  #else
>  #define efi_init()
> +#define xen_arm_enable_runtime_services() (0)
>  #endif /* CONFIG_EFI */
>
>  /* arch specific definitions used by the stub code */
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 13e3e9f..3362870 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -16,6 +16,7 @@
>  #include <asm/xen/hypervisor.h>
>  #include <asm/xen/hypercall.h>
>  #include <asm/system_misc.h>
> +#include <asm/efi.h>
>  #include <linux/interrupt.h>
>  #include <linux/irqreturn.h>
>  #include <linux/module.h>
> @@ -261,6 +262,13 @@ static int __init fdt_find_hyper_node(unsigned long 
> node, const char *uname,
>             !strncmp(hyper_node.prefix, s, strlen(hyper_node.prefix)))
>                 hyper_node.version = s + strlen(hyper_node.prefix);
>
> +       if (IS_ENABLED(CONFIG_XEN_EFI)) {
> +               /* Check if Xen supports EFI */
> +               if ((of_get_flat_dt_subnode_by_name(node, "uefi") > 0) &&
> +                   !efi_runtime_disabled())
> +                       set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
> +       }
> +
>         return 0;
>  }
>
> @@ -338,6 +346,7 @@ static int __init xen_guest_init(void)
>  {
>         struct xen_add_to_physmap xatp;
>         struct shared_info *shared_info_page = NULL;
> +       int ret;
>
>         if (!xen_domain())
>                 return 0;
> @@ -352,6 +361,13 @@ static int __init xen_guest_init(void)
>                 return -ENODEV;
>         }
>
> +       if (IS_ENABLED(CONFIG_XEN_EFI) && efi_enabled(EFI_BOOT) &&
> +           efi_enabled(EFI_RUNTIME_SERVICES)) {
> +               ret = xen_arm_enable_runtime_services();
> +               if (ret)
> +                       return ret;
> +       }
> +
>         shared_info_page = (struct shared_info *)get_zeroed_page(GFP_KERNEL);
>
>         if (!shared_info_page) {
> diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
> index 8e88a69..574bee5 100644
> --- a/arch/arm64/include/asm/efi.h
> +++ b/arch/arm64/include/asm/efi.h
> @@ -8,8 +8,10 @@
>
>  #ifdef CONFIG_EFI
>  extern void efi_init(void);
> +int xen_arm_enable_runtime_services(void);
>  #else
>  #define efi_init()
> +#define xen_arm_enable_runtime_services() (0)
>  #endif
>
>  int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
> diff --git a/drivers/firmware/efi/arm-runtime.c 
> b/drivers/firmware/efi/arm-runtime.c
> index 6ae21e4..211ec10 100644
> --- a/drivers/firmware/efi/arm-runtime.c
> +++ b/drivers/firmware/efi/arm-runtime.c
> @@ -27,6 +27,7 @@
>  #include <asm/mmu.h>
>  #include <asm/pgalloc.h>
>  #include <asm/pgtable.h>
> +#include <asm/xen/xen-ops.h>
>
>  extern u64 efi_system_table;
>
> @@ -39,6 +40,33 @@ static struct mm_struct efi_mm = {
>         .mmlist                 = LIST_HEAD_INIT(efi_mm.mmlist),
>  };
>
> +static int __init efi_remap_init(void)
> +{
> +       u64 mapsize;
> +
> +       pr_info("Remapping and enabling EFI services.\n");
> +
> +       mapsize = memmap.map_end - memmap.map;
> +       memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
> +                                                  mapsize);
> +       if (!memmap.map) {
> +               pr_err("Failed to remap EFI memory map\n");
> +               return -ENOMEM;
> +       }
> +       memmap.map_end = memmap.map + mapsize;
> +       efi.memmap = &memmap;
> +
> +       efi.systab = (__force void *)ioremap_cache(efi_system_table,
> +                                                  
> sizeof(efi_system_table_t));
> +       if (!efi.systab) {

Is there a reason why memmap.map isn't iounmap() in the error path?
The original code didn't have it either, hence the question.

Thanks,
Mathieu

> +               pr_err("Failed to remap EFI System Table\n");
> +               return -ENOMEM;
> +       }
> +       set_bit(EFI_SYSTEM_TABLES, &efi.flags);
> +
> +       return 0;
> +}
> +
>  static bool __init efi_virtmap_init(void)
>  {
>         efi_memory_desc_t *md;
> @@ -75,7 +103,7 @@ static bool __init efi_virtmap_init(void)
>   */
>  static int __init arm_enable_runtime_services(void)
>  {
> -       u64 mapsize;
> +       int ret;
>
>         if (!efi_enabled(EFI_BOOT)) {
>                 pr_info("EFI services will not be available.\n");
> @@ -87,25 +115,14 @@ static int __init arm_enable_runtime_services(void)
>                 return 0;
>         }
>
> -       pr_info("Remapping and enabling EFI services.\n");
> -
> -       mapsize = memmap.map_end - memmap.map;
> -       memmap.map = (__force void *)ioremap_cache(memmap.phys_map,
> -                                                  mapsize);
> -       if (!memmap.map) {
> -               pr_err("Failed to remap EFI memory map\n");
> -               return -ENOMEM;
> +       if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> +               pr_info("EFI runtime services access via paravirt.\n");
> +               return 0;
>         }
> -       memmap.map_end = memmap.map + mapsize;
> -       efi.memmap = &memmap;
>
> -       efi.systab = (__force void *)ioremap_cache(efi_system_table,
> -                                                  
> sizeof(efi_system_table_t));
> -       if (!efi.systab) {
> -               pr_err("Failed to remap EFI System Table\n");
> -               return -ENOMEM;
> -       }
> -       set_bit(EFI_SYSTEM_TABLES, &efi.flags);
> +       ret = efi_remap_init();
> +       if (ret)
> +               return ret;
>
>         if (!efi_virtmap_init()) {
>                 pr_err("No UEFI virtual mapping was installed -- runtime 
> services will not be available\n");
> @@ -122,6 +139,23 @@ static int __init arm_enable_runtime_services(void)
>  }
>  early_initcall(arm_enable_runtime_services);
>
> +int __init xen_arm_enable_runtime_services(void)
> +{
> +       int ret;
> +
> +       ret = efi_remap_init();
> +       if (ret)
> +               return ret;
> +
> +       if (IS_ENABLED(CONFIG_XEN_EFI)) {
> +               /* Set up runtime services function pointers for Xen Dom0 */
> +               xen_efi_runtime_setup();
> +               efi.runtime_version = efi.systab->hdr.revision;
> +       }
> +
> +       return 0;
> +}
> +
>  void efi_virtmap_load(void)
>  {
>         preempt_disable();
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 3a69ed5..f586e1e 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -469,12 +469,14 @@ device_initcall(efi_load_efivars);
>                 FIELD_SIZEOF(struct efi_fdt_params, field) \
>         }
>
> -static __initdata struct {
> +struct params {
>         const char name[32];
>         const char propname[32];
>         int offset;
>         int size;
> -} dt_params[] = {
> +};
> +
> +static __initdata struct params fdt_params[] = {
>         UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
>         UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
>         UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
> @@ -482,44 +484,91 @@ static __initdata struct {
>         UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", 
> desc_ver)
>  };
>
> +static __initdata struct params xen_fdt_params[] = {
> +       UEFI_PARAM("System Table", "xen,uefi-system-table", system_table),
> +       UEFI_PARAM("MemMap Address", "xen,uefi-mmap-start", mmap),
> +       UEFI_PARAM("MemMap Size", "xen,uefi-mmap-size", mmap_size),
> +       UEFI_PARAM("MemMap Desc. Size", "xen,uefi-mmap-desc-size", desc_size),
> +       UEFI_PARAM("MemMap Desc. Version", "xen,uefi-mmap-desc-ver", desc_ver)
> +};
> +
> +#define EFI_FDT_PARAMS_SIZE    ARRAY_SIZE(fdt_params)
> +
> +static __initdata struct {
> +       const char *uname;
> +       const char *subnode;
> +       struct params *params;
> +} dt_params[] = {
> +       { "hypervisor", "uefi", xen_fdt_params },
> +       { "chosen", NULL, fdt_params },
> +};
> +
>  struct param_info {
>         int found;
>         void *params;
> +       const char *missing;
>  };
>
> -static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
> -                                      int depth, void *data)
> +static int __init __find_uefi_params(unsigned long node,
> +                                    struct param_info *info,
> +                                    struct params *params)
>  {
> -       struct param_info *info = data;
>         const void *prop;
>         void *dest;
>         u64 val;
>         int i, len;
>
> -       if (depth != 1 || strcmp(uname, "chosen") != 0)
> -               return 0;
> -
> -       for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
> -               prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
> -               if (!prop)
> +       for (i = 0; i < EFI_FDT_PARAMS_SIZE; i++) {
> +               prop = of_get_flat_dt_prop(node, params[i].propname, &len);
> +               if (!prop) {
> +                       info->missing = params[i].name;
>                         return 0;
> -               dest = info->params + dt_params[i].offset;
> +               }
> +
> +               dest = info->params + params[i].offset;
>                 info->found++;
>
>                 val = of_read_number(prop, len / sizeof(u32));
>
> -               if (dt_params[i].size == sizeof(u32))
> +               if (params[i].size == sizeof(u32))
>                         *(u32 *)dest = val;
>                 else
>                         *(u64 *)dest = val;
>
>                 if (efi_enabled(EFI_DBG))
> -                       pr_info("  %s: 0x%0*llx\n", dt_params[i].name,
> -                               dt_params[i].size * 2, val);
> +                       pr_info("  %s: 0x%0*llx\n", params[i].name,
> +                               params[i].size * 2, val);
>         }
> +
>         return 1;
>  }
>
> +static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
> +                                      int depth, void *data)
> +{
> +       struct param_info *info = data;
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
> +               const char *subnode = dt_params[i].subnode;
> +
> +               if (depth != 1 || strcmp(uname, dt_params[i].uname) != 0) {
> +                       info->missing = dt_params[i].params[0].name;
> +                       continue;
> +               }
> +
> +               if (subnode) {
> +                       node = of_get_flat_dt_subnode_by_name(node, subnode);
> +                       if (node < 0)
> +                               return 0;
> +               }
> +
> +               return __find_uefi_params(node, info, dt_params[i].params);
> +       }
> +
> +       return 0;
> +}
> +
>  int __init efi_get_fdt_params(struct efi_fdt_params *params)
>  {
>         struct param_info info;
> @@ -535,7 +584,7 @@ int __init efi_get_fdt_params(struct efi_fdt_params 
> *params)
>                 pr_info("UEFI not found.\n");
>         else if (!ret)
>                 pr_err("Can't find '%s' in device tree!\n",
> -                      dt_params[info.found].name);
> +                      info.missing);
>
>         return ret;
>  }
> --
> 2.0.4
>
>
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