[PATCHv9 10/14] x86/mm: Provide helpers for unaccepted memory

From: Kirill A. Shutemov
Date: Thu Mar 30 2023 - 07:50:50 EST


Core-mm requires few helpers to support unaccepted memory:

- accept_memory() checks the range of addresses against the bitmap and
accept memory if needed.

- range_contains_unaccepted_memory() checks if anything within the
range requires acceptance.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/page.h | 3 ++
arch/x86/include/asm/unaccepted_memory.h | 4 ++
arch/x86/mm/Makefile | 2 +
arch/x86/mm/unaccepted_memory.c | 61 ++++++++++++++++++++++++
4 files changed, 70 insertions(+)
create mode 100644 arch/x86/mm/unaccepted_memory.c

diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index d18e5c332cb9..4bab2bb2c9c0 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -19,6 +19,9 @@
struct page;

#include <linux/range.h>
+
+#include <asm/unaccepted_memory.h>
+
extern struct range pfn_mapped[];
extern int nr_pfn_mapped;

diff --git a/arch/x86/include/asm/unaccepted_memory.h b/arch/x86/include/asm/unaccepted_memory.h
index 41fbfc798100..89fc91c61560 100644
--- a/arch/x86/include/asm/unaccepted_memory.h
+++ b/arch/x86/include/asm/unaccepted_memory.h
@@ -7,6 +7,10 @@ struct boot_params;

void process_unaccepted_memory(struct boot_params *params, u64 start, u64 num);

+#ifdef CONFIG_UNACCEPTED_MEMORY
+
void accept_memory(phys_addr_t start, phys_addr_t end);
+bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end);

#endif
+#endif
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index c80febc44cd2..b0ef1755e5c8 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -67,3 +67,5 @@ obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_amd.o

obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o
obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o
+
+obj-$(CONFIG_UNACCEPTED_MEMORY) += unaccepted_memory.o
diff --git a/arch/x86/mm/unaccepted_memory.c b/arch/x86/mm/unaccepted_memory.c
new file mode 100644
index 000000000000..1df918b21469
--- /dev/null
+++ b/arch/x86/mm/unaccepted_memory.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/memblock.h>
+#include <linux/mm.h>
+#include <linux/pfn.h>
+#include <linux/spinlock.h>
+
+#include <asm/io.h>
+#include <asm/setup.h>
+#include <asm/unaccepted_memory.h>
+
+/* Protects unaccepted memory bitmap */
+static DEFINE_SPINLOCK(unaccepted_memory_lock);
+
+void accept_memory(phys_addr_t start, phys_addr_t end)
+{
+ unsigned long range_start, range_end;
+ unsigned long *bitmap;
+ unsigned long flags;
+
+ if (!boot_params.unaccepted_memory)
+ return;
+
+ bitmap = __va(boot_params.unaccepted_memory);
+ range_start = start / PMD_SIZE;
+
+ spin_lock_irqsave(&unaccepted_memory_lock, flags);
+ for_each_set_bitrange_from(range_start, range_end, bitmap,
+ DIV_ROUND_UP(end, PMD_SIZE)) {
+ unsigned long len = range_end - range_start;
+
+ /* Platform-specific memory-acceptance call goes here */
+ panic("Cannot accept memory: unknown platform\n");
+ bitmap_clear(bitmap, range_start, len);
+ }
+ spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
+}
+
+bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end)
+{
+ unsigned long *bitmap;
+ unsigned long flags;
+ bool ret = false;
+
+ if (!boot_params.unaccepted_memory)
+ return 0;
+
+ bitmap = __va(boot_params.unaccepted_memory);
+
+ spin_lock_irqsave(&unaccepted_memory_lock, flags);
+ while (start < end) {
+ if (test_bit(start / PMD_SIZE, bitmap)) {
+ ret = true;
+ break;
+ }
+
+ start += PMD_SIZE;
+ }
+ spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
+
+ return ret;
+}
--
2.39.2