[RFC][PATCH 2/2] arm: grub-install: Default to arm-efi target in EFI-based QEMU virt models

[dann frazier]

From: dann frazier <address@hidden>

We currently default to the arm-uboot target in grub-install,
but arm-efi should be used for some systems with UEFI firmware, such as
Tianocore/EDK2-based QEMU models. We could change the default to arm-efi
anytime we successfully probe for an EFI runtime. However, that would
apparently do the wrong thing on U-Boot implementations that implement the
UEFI spec, such as those compliant with the upcoming Embedded Base Boot
Requirements specification, as they are not required to support
SetVariable() in runtime services.

For now, whitelist QEMU linux/virt models with runtime EFI support,
but otherwise continue to default to the arm-uboot target.

Signed-off-by: dann frazier <address@hidden>
---
 grub-core/osdep/basic/platform.c   |  6 +++++
 grub-core/osdep/linux/platform.c   | 37 ++++++++++++++++++++++++++++++
 grub-core/osdep/windows/platform.c |  6 +++++
 include/grub/util/install.h        |  3 +++
 util/grub-install.c                |  2 +-
 5 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/grub-core/osdep/basic/platform.c b/grub-core/osdep/basic/platform.c
index 4b5502aeb..a7dafd85a 100644
--- a/grub-core/osdep/basic/platform.c
+++ b/grub-core/osdep/basic/platform.c
@@ -18,6 +18,12 @@
 
 #include <grub/util/install.h>
 
+const char *
+grub_install_get_default_arm_platform (void)
+{
+  return "arm-uboot";
+}
+
 const char *
 grub_install_get_default_x86_platform (void)
 { 
diff --git a/grub-core/osdep/linux/platform.c b/grub-core/osdep/linux/platform.c
index d278c299b..835aa4856 100644
--- a/grub-core/osdep/linux/platform.c
+++ b/grub-core/osdep/linux/platform.c
@@ -121,6 +121,43 @@ is_efi (void)
   return 0;
 }
 
+static int
+is_virt (void)
+{
+  FILE *fp;
+  char *buf = NULL;
+  int ret = 0;
+  size_t len = 0;
+  const char qemu_virt[] = "linux,dummy-virt";
+
+  fp = grub_util_fopen ("/sys/firmware/devicetree/base/compatible", "r");
+  if (fp == NULL)
+    return 0;
+
+  if (getline (&buf, &len, fp) == -1)
+    {
+      fclose (fp);
+      return 0;
+    }
+
+  if (strncmp (buf, qemu_virt, len) == 0)
+    ret = 1;
+
+  free (buf);
+  fclose (fp);
+
+  return ret;
+}
+
+const char *
+grub_install_get_default_arm_platform (void)
+{
+  if (is_efi() && is_virt())
+      return "arm-efi";
+
+  return "arm-uboot";
+}
+
 const char *
 grub_install_get_default_x86_platform (void)
 {
diff --git a/grub-core/osdep/windows/platform.c 
b/grub-core/osdep/windows/platform.c
index 58b322887..2dabd1758 100644
--- a/grub-core/osdep/windows/platform.c
+++ b/grub-core/osdep/windows/platform.c
@@ -116,6 +116,12 @@ is_efi (void)
   return platform == PLAT_EFI;
 }
 
+const char *
+grub_install_get_default_arm_platform (void)
+{
+  return "arm-uboot";
+}
+
 const char *
 grub_install_get_default_x86_platform (void)
 { 
diff --git a/include/grub/util/install.h b/include/grub/util/install.h
index 0dba8b67f..212ada422 100644
--- a/include/grub/util/install.h
+++ b/include/grub/util/install.h
@@ -207,6 +207,9 @@ grub_util_get_target_dirname (const struct 
grub_install_image_target_desc *t);
 void
 grub_install_create_envblk_file (const char *name);
 
+const char *
+grub_install_get_default_arm_platform (void);
+
 const char *
 grub_install_get_default_x86_platform (void);
 
diff --git a/util/grub-install.c b/util/grub-install.c
index 78d0138cb..81bbec778 100644
--- a/util/grub-install.c
+++ b/util/grub-install.c
@@ -319,7 +319,7 @@ get_default_platform (void)
 #elif defined (__ia64__)
    return "ia64-efi";
 #elif defined (__arm__)
-   return "arm-uboot";
+   return grub_install_get_default_arm_platform ();
 #elif defined (__aarch64__)
    return "arm64-efi";
 #elif defined (__amd64__) || defined (__x86_64__) || defined (__i386__)
-- 
2.18.0