[PATCH v4 03/23] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance

[Dan Williams]

In preparation for attaching a platform device per iomem resource teach
the efi_fake_mem code to create an e820 entry per instance. Similar to
E820_TYPE_PRAM, bypass merging resource when the e820 map is sanitized.

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Acked-by: Ard Biesheuvel <a...@kernel.org>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 arch/x86/kernel/e820.c              |   16 +++++++++++++++-
 drivers/firmware/efi/x86_fake_mem.c |   12 +++++++++---
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 983cd53ed4c9..22aad412f965 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -305,6 +305,20 @@ static int __init cpcompare(const void *a, const void *b)
        return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
 }
 
+static bool e820_nomerge(enum e820_type type)
+{
+       /*
+        * These types may indicate distinct platform ranges aligned to
+        * numa node, protection domain, performance domain, or other
+        * boundaries. Do not merge them.
+        */
+       if (type == E820_TYPE_PRAM)
+               return true;
+       if (type == E820_TYPE_SOFT_RESERVED)
+               return true;
+       return false;
+}
+
 int __init e820__update_table(struct e820_table *table)
 {
        struct e820_entry *entries = table->entries;
@@ -380,7 +394,7 @@ int __init e820__update_table(struct e820_table *table)
                }
 
                /* Continue building up new map based on this information: */
-               if (current_type != last_type || current_type == 
E820_TYPE_PRAM) {
+               if (current_type != last_type || e820_nomerge(current_type)) {
                        if (last_type != 0)      {
                                new_entries[new_nr_entries].size = 
change_point[chg_idx]->addr - last_addr;
                                /* Move forward only if the new size was 
non-zero: */
diff --git a/drivers/firmware/efi/x86_fake_mem.c 
b/drivers/firmware/efi/x86_fake_mem.c
index e5d6d5a1b240..0bafcc1bb0f6 100644
--- a/drivers/firmware/efi/x86_fake_mem.c
+++ b/drivers/firmware/efi/x86_fake_mem.c
@@ -38,7 +38,7 @@ void __init efi_fake_memmap_early(void)
                m_start = mem->range.start;
                m_end = mem->range.end;
                for_each_efi_memory_desc(md) {
-                       u64 start, end;
+                       u64 start, end, size;
 
                        if (md->type != EFI_CONVENTIONAL_MEMORY)
                                continue;
@@ -58,11 +58,17 @@ void __init efi_fake_memmap_early(void)
                         */
                        start = max(start, m_start);
                        end = min(end, m_end);
+                       size = end - start + 1;
 
                        if (end <= start)
                                continue;
-                       e820__range_update(start, end - start + 1, 
E820_TYPE_RAM,
-                                       E820_TYPE_SOFT_RESERVED);
+
+                       /*
+                        * Ensure each efi_fake_mem instance results in
+                        * a unique e820 resource
+                        */
+                       e820__range_remove(start, size, E820_TYPE_RAM, 1);
+                       e820__range_add(start, size, E820_TYPE_SOFT_RESERVED);
                        e820__update_table(e820_table);
                }
        }