1 files changed, 92 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/reserved_mem.c b/arch/arm64/kvm/hyp/reserved_mem.c
new file mode 100644
index 000000000000..9bc6a6d27904
--- /dev/null
+++ b/arch/arm64/kvm/hyp/reserved_mem.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: Quentin Perret <qperret@google.com>
+ */
+
+#include <linux/kvm_host.h>
+#include <linux/memblock.h>
+
+#include <asm/kvm_host.h>
+
+#include <nvhe/memory.h>
+#include <nvhe/mm.h>
+
+static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
+static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
+
+phys_addr_t hyp_mem_base;
+phys_addr_t hyp_mem_size;
+
+static int __init register_memblock_regions(void)
+{
+	struct memblock_region *reg;
+
+	for_each_mem_region(reg) {
+		if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS)
+			return -ENOMEM;
+
+		hyp_memory[*hyp_memblock_nr_ptr] = *reg;
+		(*hyp_memblock_nr_ptr)++;
+	}
+
+	return 0;
+}
+
+void __init kvm_hyp_reserve(void)
+{
+	u64 nr_pages, prev, hyp_mem_pages = 0;
+	int ret;
+
+	if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())
+		return;
+
+	if (kvm_get_mode() != KVM_MODE_PROTECTED)
+		return;
+
+	ret = register_memblock_regions();
+	if (ret) {
+		*hyp_memblock_nr_ptr = 0;
+		kvm_err("Failed to register hyp memblocks: %d\n", ret);
+		return;
+	}
+
+	hyp_mem_pages += hyp_s1_pgtable_pages();
+
+	/*
+	 * The hyp_vmemmap needs to be backed by pages, but these pages
+	 * themselves need to be present in the vmemmap, so compute the number
+	 * of pages needed by looking for a fixed point.
+	 */
+	nr_pages = 0;
+	do {
+		prev = nr_pages;
+		nr_pages = hyp_mem_pages + prev;
+		nr_pages = DIV_ROUND_UP(nr_pages * sizeof(struct hyp_page), PAGE_SIZE);
+		nr_pages += __hyp_pgtable_max_pages(nr_pages);
+	} while (nr_pages != prev);
+	hyp_mem_pages += nr_pages;
+
+	/*
+	 * Try to allocate a PMD-aligned region to reduce TLB pressure once
+	 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE.
+	 */
+	hyp_mem_size = hyp_mem_pages << PAGE_SHIFT;
+	hyp_mem_base = memblock_find_in_range(0, memblock_end_of_DRAM(),
+					      ALIGN(hyp_mem_size, PMD_SIZE),
+					      PMD_SIZE);
+	if (!hyp_mem_base)
+		hyp_mem_base = memblock_find_in_range(0, memblock_end_of_DRAM(),
+						      hyp_mem_size, PAGE_SIZE);
+	else
+		hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE);
+
+	if (!hyp_mem_base) {
+		kvm_err("Failed to reserve hyp memory\n");
+		return;
+	}
+	memblock_reserve(hyp_mem_base, hyp_mem_size);
+
+	kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20,
+		 hyp_mem_base);
+}