Re: EFI and multiboot2 devlopment work for Xen

From: Konrad Rzeszutek Wilk
Date: Mon Oct 28 2013 - 12:28:09 EST


On Tue, Oct 22, 2013 at 10:54:44AM +0200, Vladimir 'Ï-coder/phcoder' Serbinenko wrote:
> On 21.10.2013 23:16, Vladimir 'Ï-coder/phcoder' Serbinenko wrote:
> > Mail is big, I think I got your essential points but I didn't read it whole.
> > On 21.10.2013 14:57, Daniel Kiper wrote:
> >> Hi,
> >>
> >> During work on multiboot2 protocol support for Xen it was discovered
> >> that memory map passed via relevant tag could not represent wide range
> >> of memory types available on EFI platforms. Additionally, GRUB2
> >> implementation calls ExitBootServices() on them just before jumping
> >> into loaded image. In this situation loaded system could not clearly
> >> identify reserved memory regions, EFI runtime services regions and others.
> >>
> > Will a multiboot2 tag with whole EFI memory map solve your problem?
> I added such a tag in documentation and wrote a patch for it (attached).
> Awaiting for someone to test it to commit

Great! I think from Xen perspective we first need to have Xen be able
to understand multiboot2 - that is something Daniel had been working on.
I will let Daniel talk more about it.

Seth, would you have any time to test the patch against Solaris to
make sure it works?

Thanks!
>




=== modified file 'grub-core/loader/i386/multiboot_mbi.c'
--- grub-core/loader/i386/multiboot_mbi.c 2013-10-14 14:33:44 +0000
+++ grub-core/loader/i386/multiboot_mbi.c 2013-10-22 06:57:45 +0000
@@ -36,6 +36,10 @@
#include <grub/net.h>
#include <grub/i18n.h>

+#ifdef GRUB_MACHINE_EFI
+#include <grub/efi/efi.h>
+#endif
+
/* The bits in the required part of flags field we don't support. */
#define UNSUPPORTED_FLAGS 0x0000fff8

@@ -579,6 +583,12 @@
ptrdest += sizeof (struct grub_vbe_mode_info_block);
#endif

+#ifdef GRUB_MACHINE_EFI
+ err = grub_efi_finish_boot_services (NULL, NULL, NULL, NULL, NULL);
+ if (err)
+ return err;
+#endif
+
return GRUB_ERR_NONE;
}


=== modified file 'grub-core/loader/multiboot.c'
--- grub-core/loader/multiboot.c 2013-09-23 11:35:33 +0000
+++ grub-core/loader/multiboot.c 2013-10-22 06:51:30 +0000
@@ -131,12 +131,6 @@
if (err)
return err;

-#ifdef GRUB_MACHINE_EFI
- err = grub_efi_finish_boot_services (NULL, NULL, NULL, NULL, NULL);
- if (err)
- return err;
-#endif
-
#if defined (__i386__) || defined (__x86_64__)
grub_relocator32_boot (grub_multiboot_relocator, state, 0);
#else

=== modified file 'grub-core/loader/multiboot_mbi2.c'
--- grub-core/loader/multiboot_mbi2.c 2013-10-14 14:33:44 +0000
+++ grub-core/loader/multiboot_mbi2.c 2013-10-22 06:57:58 +0000
@@ -295,9 +295,55 @@
#endif
}

+#ifdef GRUB_MACHINE_EFI
+
+static grub_efi_uintn_t efi_mmap_size = 0;
+
+/* Find the optimal number of pages for the memory map. Is it better to
+ move this code to efi/mm.c? */
+static void
+find_efi_mmap_size (void)
+{
+ efi_mmap_size = (1 << 12);
+ while (1)
+ {
+ int ret;
+ grub_efi_memory_descriptor_t *mmap;
+ grub_efi_uintn_t desc_size;
+ grub_efi_uintn_t cur_mmap_size = efi_mmap_size;
+
+ mmap = grub_malloc (cur_mmap_size);
+ if (! mmap)
+ return;
+
+ ret = grub_efi_get_memory_map (&cur_mmap_size, mmap, 0, &desc_size, 0);
+ grub_free (mmap);
+
+ if (ret < 0)
+ return;
+ else if (ret > 0)
+ break;
+
+ if (efi_mmap_size < cur_mmap_size)
+ efi_mmap_size = cur_mmap_size;
+ efi_mmap_size += (1 << 12);
+ }
+
+ /* Increase the size a bit for safety, because GRUB allocates more on
+ later, and EFI itself may allocate more. */
+ efi_mmap_size += (3 << 12);
+
+ efi_mmap_size = ALIGN_UP (efi_mmap_size, 4096);
+}
+#endif
+
static grub_size_t
grub_multiboot_get_mbi_size (void)
{
+#ifdef GRUB_MACHINE_EFI
+ if (!efi_mmap_size)
+ find_efi_mmap_size ();
+#endif
return 2 * sizeof (grub_uint32_t) + sizeof (struct multiboot_tag)
+ (sizeof (struct multiboot_tag_string)
+ ALIGN_UP (cmdline_size, MULTIBOOT_TAG_ALIGN))
@@ -318,6 +364,10 @@
+ ALIGN_UP (sizeof (struct multiboot_tag_old_acpi)
+ sizeof (struct grub_acpi_rsdp_v10), MULTIBOOT_TAG_ALIGN)
+ acpiv2_size ()
+#ifdef GRUB_MACHINE_EFI
+ + ALIGN_UP (sizeof (struct multiboot_tag_efi_mmap)
+ + efi_mmap_size, MULTIBOOT_TAG_ALIGN)
+#endif
+ sizeof (struct multiboot_tag_vbe) + MULTIBOOT_TAG_ALIGN - 1
+ sizeof (struct multiboot_tag_apm) + MULTIBOOT_TAG_ALIGN - 1;
}
@@ -760,6 +810,28 @@
}
#endif

+#ifdef GRUB_MACHINE_EFI
+ {
+ struct multiboot_tag_efi_mmap *tag = (struct multiboot_tag_efi_mmap *) ptrorig;
+ grub_efi_uintn_t efi_desc_size;
+ grub_efi_uint32_t efi_desc_version;
+
+ tag->type = MULTIBOOT_TAG_TYPE_EFI_MMAP;
+ tag->size = sizeof (*tag) + efi_mmap_size;
+
+ err = grub_efi_finish_boot_services (&efi_mmap_size, tag->efi_mmap, NULL,
+ &efi_desc_size, &efi_desc_version);
+ if (err)
+ return err;
+ tag->descr_size = efi_desc_size;
+ tag->descr_vers = efi_desc_version;
+ tag->size = sizeof (*tag) + efi_mmap_size;
+
+ ptrorig += ALIGN_UP (tag->size, MULTIBOOT_TAG_ALIGN)
+ / sizeof (grub_properly_aligned_t);
+ }
+#endif
+
{
struct multiboot_tag *tag = (struct multiboot_tag *) ptrorig;
tag->type = MULTIBOOT_TAG_TYPE_END;

=== modified file 'include/multiboot2.h'
--- include/multiboot2.h 2010-09-21 00:06:14 +0000
+++ include/multiboot2.h 2013-10-22 06:37:55 +0000
@@ -58,6 +58,7 @@
#define MULTIBOOT_TAG_TYPE_ACPI_OLD 14
#define MULTIBOOT_TAG_TYPE_ACPI_NEW 15
#define MULTIBOOT_TAG_TYPE_NETWORK 16
+#define MULTIBOOT_TAG_TYPE_EFI_MMAP 17

#define MULTIBOOT_HEADER_TAG_END 0
#define MULTIBOOT_HEADER_TAG_INFORMATION_REQUEST 1
@@ -361,6 +362,15 @@
multiboot_uint8_t dhcpack[0];
};

+struct multiboot_tag_efi_mmap
+{
+ multiboot_uint32_t type;
+ multiboot_uint32_t size;
+ multiboot_uint32_t descr_size;
+ multiboot_uint32_t descr_vers;
+ multiboot_uint8_t efi_mmap[0];
+};
+
#endif /* ! ASM_FILE */

#endif /* ! MULTIBOOT_HEADER */