[PATCH v3 03/23] efi/fake_mem: Arrange for a resource entry per efi_fake_mem instance

Dan Williams
2020-08-01T03:41:39Z

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 <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@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);
}
}