[Xen-devel] [PATCH 2/6] xen: factor out allocation of special pages into separate function

[Juergen Gross <jgross@xxxxxxxx>]

Do the allocation of special pages (start info, console and xenbus
ring buffers) in a separate function. This will allow to do the
allocation at different times of the boot preparations depending on
the features the kernel is supporting.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 grub-core/loader/i386/xen.c | 50 +++++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/grub-core/loader/i386/xen.c b/grub-core/loader/i386/xen.c
index 42ed7c7..e48cc3f 100644
--- a/grub-core/loader/i386/xen.c
+++ b/grub-core/loader/i386/xen.c
@@ -54,6 +54,8 @@ static grub_uint64_t modules_target_start;
 static grub_size_t n_modules;
 static struct grub_relocator_xen_state state;
 static grub_xen_mfn_t *virt_mfn_list;
+static struct start_info *virt_start_info;
+static grub_xen_mfn_t console_pfn;
 
 #define PAGE_SIZE 4096
 #define MAX_MODULES (PAGE_SIZE / sizeof (struct xen_multiboot_mod_list))
@@ -232,43 +234,51 @@ grub_xen_p2m_alloc (void)
 }
 
 static grub_err_t
-grub_xen_boot (void)
+grub_xen_special_alloc (void)
 {
   grub_relocator_chunk_t ch;
   grub_err_t err;
-  struct start_info *nst;
-  grub_uint64_t nr_info_pages;
-  grub_uint64_t nr_pages, nr_pt_pages, nr_need_pages;
-  struct gnttab_set_version gnttab_setver;
-  grub_size_t i;
-
-  if (grub_xen_n_allocated_shared_pages)
-    return grub_error (GRUB_ERR_BUG, "active grants");
-
-  err = grub_xen_p2m_alloc ();
-  if (err)
-    return err;
 
   err = grub_relocator_alloc_chunk_addr (relocator, &ch,
                                         max_addr, sizeof (next_start));
   if (err)
     return err;
   state.start_info = max_addr + xen_inf.virt_base;
-  nst = get_virtual_current_address (ch);
+  virt_start_info = get_virtual_current_address (ch);
   max_addr = ALIGN_UP (max_addr + sizeof (next_start), PAGE_SIZE);
+  console_pfn = max_addr >> PAGE_SHIFT;
+  max_addr += 2 * PAGE_SIZE;
 
   next_start.nr_pages = grub_xen_start_page_addr->nr_pages;
   grub_memcpy (next_start.magic, grub_xen_start_page_addr->magic,
               sizeof (next_start.magic));
+  next_start.shared_info = grub_xen_start_page_addr->shared_info;
   next_start.store_mfn = grub_xen_start_page_addr->store_mfn;
   next_start.store_evtchn = grub_xen_start_page_addr->store_evtchn;
   next_start.console.domU = grub_xen_start_page_addr->console.domU;
-  next_start.shared_info = grub_xen_start_page_addr->shared_info;
 
-  err = set_mfns (max_addr >> PAGE_SHIFT);
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_xen_boot (void)
+{
+  grub_relocator_chunk_t ch;
+  grub_err_t err;
+  grub_uint64_t nr_info_pages;
+  grub_uint64_t nr_pages, nr_pt_pages, nr_need_pages;
+  struct gnttab_set_version gnttab_setver;
+  grub_size_t i;
+
+  if (grub_xen_n_allocated_shared_pages)
+    return grub_error (GRUB_ERR_BUG, "active grants");
+
+  err = grub_xen_p2m_alloc ();
+  if (err)
+    return err;
+  err = grub_xen_special_alloc ();
   if (err)
     return err;
-  max_addr += 2 * PAGE_SIZE;
 
   next_start.pt_base = max_addr + xen_inf.virt_base;
   state.paging_start = max_addr >> PAGE_SHIFT;
@@ -297,6 +307,10 @@ grub_xen_boot (void)
   if (err)
     return err;
 
+  err = set_mfns (console_pfn);
+  if (err)
+    return err;
+
   generate_page_table (get_virtual_current_address (ch),
                       max_addr >> PAGE_SHIFT, nr_pages,
                       xen_inf.virt_base, virt_mfn_list);
@@ -308,7 +322,7 @@ grub_xen_boot (void)
   next_start.nr_pt_frames = nr_pt_pages;
   state.paging_size = nr_pt_pages;
 
-  *nst = next_start;
+  *virt_start_info = next_start;
 
   grub_memset (&gnttab_setver, 0, sizeof (gnttab_setver));
 
-- 
2.1.4


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