On Mon, 2 Mar 2020 at 23:36, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
> 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 c5399e80c59c..96babb3a6629 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);
> }
> }
>
