[RFC PATCH 25/27] KVM: arm64: Reserve memory for host stage 2

[Quentin Perret <qperret@xxxxxxxxxx>]

Extend the memory pool allocated for the hypervisor to include enough
pages to map all of memory at page granularity for the host stage 2.
While at it, also reserve some memory for device mappings.

Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
---
 arch/arm64/kvm/hyp/include/nvhe/mm.h | 36 ++++++++++++++++++++++++----
 arch/arm64/kvm/hyp/nvhe/setup.c      | 12 ++++++++++
 arch/arm64/kvm/hyp/reserved_mem.c    |  2 ++
 3 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h
index 5a3ad6f4e5bc..b79be2580164 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h
@@ -52,15 +52,12 @@ static inline unsigned long __hyp_pgtable_max_pages(unsigned long nr_pages)
 	return total;
 }
 
-static inline unsigned long hyp_s1_pgtable_size(void)
+static inline unsigned long __hyp_pgtable_total_size(void)
 {
 	struct hyp_memblock_region *reg;
 	unsigned long nr_pages, res = 0;
 	int i;
 
-	if (kvm_nvhe_sym(hyp_memblock_nr) <= 0)
-		return 0;
-
 	for (i = 0; i < kvm_nvhe_sym(hyp_memblock_nr); i++) {
 		reg = &kvm_nvhe_sym(hyp_memory)[i];
 		nr_pages = (reg->end - reg->start) >> PAGE_SHIFT;
@@ -68,6 +65,18 @@ static inline unsigned long hyp_s1_pgtable_size(void)
 		res += nr_pages << PAGE_SHIFT;
 	}
 
+	return res;
+}
+
+static inline unsigned long hyp_s1_pgtable_size(void)
+{
+	unsigned long res, nr_pages;
+
+	if (kvm_nvhe_sym(hyp_memblock_nr) <= 0)
+		return 0;
+
+	res = __hyp_pgtable_total_size();
+
 	/* Allow 1 GiB for private mappings */
 	nr_pages = (1 << 30) >> PAGE_SHIFT;
 	nr_pages = __hyp_pgtable_max_pages(nr_pages);
@@ -76,4 +85,23 @@ static inline unsigned long hyp_s1_pgtable_size(void)
 	return res;
 }
 
+static inline unsigned long host_s2_mem_pgtable_size(void)
+{
+	unsigned long max_pgd_sz = 16 << PAGE_SHIFT;
+
+	if (kvm_nvhe_sym(hyp_memblock_nr) <= 0)
+		return 0;
+
+	return __hyp_pgtable_total_size() + max_pgd_sz;
+}
+
+static inline unsigned long host_s2_dev_pgtable_size(void)
+{
+	if (kvm_nvhe_sym(hyp_memblock_nr) <= 0)
+		return 0;
+
+	/* Allow 1 GiB for private mappings */
+	return __hyp_pgtable_max_pages((1 << 30) >> PAGE_SHIFT) << PAGE_SHIFT;
+}
+
 #endif /* __KVM_HYP_MM_H */
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 9679c97b875b..b73e6b08cfba 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -24,6 +24,8 @@ unsigned long hyp_nr_cpus;
 static void *stacks_base;
 static void *vmemmap_base;
 static void *hyp_pgt_base;
+static void *host_s2_mem_pgt_base;
+static void *host_s2_dev_pgt_base;
 
 static int divide_memory_pool(void *virt, unsigned long size)
 {
@@ -46,6 +48,16 @@ static int divide_memory_pool(void *virt, unsigned long size)
 	if (!hyp_pgt_base)
 		return -ENOMEM;
 
+	nr_pages = host_s2_mem_pgtable_size() >> PAGE_SHIFT;
+	host_s2_mem_pgt_base = hyp_early_alloc_contig(nr_pages);
+	if (!host_s2_mem_pgt_base)
+		return -ENOMEM;
+
+	nr_pages = host_s2_dev_pgtable_size() >> PAGE_SHIFT;
+	host_s2_dev_pgt_base = hyp_early_alloc_contig(nr_pages);
+	if (!host_s2_dev_pgt_base)
+		return -ENOMEM;
+
 	return 0;
 }
 
diff --git a/arch/arm64/kvm/hyp/reserved_mem.c b/arch/arm64/kvm/hyp/reserved_mem.c
index 02b0b18006f5..c2c0484b6211 100644
--- a/arch/arm64/kvm/hyp/reserved_mem.c
+++ b/arch/arm64/kvm/hyp/reserved_mem.c
@@ -47,6 +47,8 @@ void __init reserve_kvm_hyp(void)
 
 	hyp_mem_size += num_possible_cpus() << PAGE_SHIFT;
 	hyp_mem_size += hyp_s1_pgtable_size();
+	hyp_mem_size += host_s2_mem_pgtable_size();
+	hyp_mem_size += host_s2_dev_pgtable_size();
 
 	/*
 	 * The hyp_vmemmap needs to be backed by pages, but these pages
-- 
2.29.2.299.gdc1121823c-goog