KVM: arm64: Factor memory allocation out of pgtable.c

In preparation for enabling the creation of page-tables at EL2, factor
all memory allocation out of the page-table code, hence making it
re-usable with any compatible memory allocator.

No functional changes intended.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-7-qperret@google.com

1 files changed, 64 insertions, 2 deletions

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 8711894db8c2..e583f7fb3620 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -88,6 +88,44 @@ static bool kvm_is_device_pfn(unsigned long pfn)
 	return !pfn_valid(pfn);
 }
 
+static void *stage2_memcache_zalloc_page(void *arg)
+{
+	struct kvm_mmu_memory_cache *mc = arg;
+
+	/* Allocated with __GFP_ZERO, so no need to zero */
+	return kvm_mmu_memory_cache_alloc(mc);
+}
+
+static void *kvm_host_zalloc_pages_exact(size_t size)
+{
+	return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
+}
+
+static void kvm_host_get_page(void *addr)
+{
+	get_page(virt_to_page(addr));
+}
+
+static void kvm_host_put_page(void *addr)
+{
+	put_page(virt_to_page(addr));
+}
+
+static int kvm_host_page_count(void *addr)
+{
+	return page_count(virt_to_page(addr));
+}
+
+static phys_addr_t kvm_host_pa(void *addr)
+{
+	return __pa(addr);
+}
+
+static void *kvm_host_va(phys_addr_t phys)
+{
+	return __va(phys);
+}
+
 /*
  * Unmapping vs dcache management:
  *
@@ -351,6 +389,17 @@ int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
 	return 0;
 }
 
+static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
+	.zalloc_page		= stage2_memcache_zalloc_page,
+	.zalloc_pages_exact	= kvm_host_zalloc_pages_exact,
+	.free_pages_exact	= free_pages_exact,
+	.get_page		= kvm_host_get_page,
+	.put_page		= kvm_host_put_page,
+	.page_count		= kvm_host_page_count,
+	.phys_to_virt		= kvm_host_va,
+	.virt_to_phys		= kvm_host_pa,
+};
+
 /**
  * kvm_init_stage2_mmu - Initialise a S2 MMU strucrure
  * @kvm:	The pointer to the KVM structure
@@ -374,7 +423,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
 	if (!pgt)
 		return -ENOMEM;
 
-	err = kvm_pgtable_stage2_init(pgt, kvm);
+	err = kvm_pgtable_stage2_init(pgt, kvm, &kvm_s2_mm_ops);
 	if (err)
 		goto out_free_pgtable;
 
@@ -1208,6 +1257,19 @@ static int kvm_map_idmap_text(void)
 	return err;
 }
 
+static void *kvm_hyp_zalloc_page(void *arg)
+{
+	return (void *)get_zeroed_page(GFP_KERNEL);
+}
+
+static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = {
+	.zalloc_page		= kvm_hyp_zalloc_page,
+	.get_page		= kvm_host_get_page,
+	.put_page		= kvm_host_put_page,
+	.phys_to_virt		= kvm_host_va,
+	.virt_to_phys		= kvm_host_pa,
+};
+
 int kvm_mmu_init(void)
 {
 	int err;
@@ -1251,7 +1313,7 @@ int kvm_mmu_init(void)
 		goto out;
 	}
 
-	err = kvm_pgtable_hyp_init(hyp_pgtable, hyp_va_bits);
+	err = kvm_pgtable_hyp_init(hyp_pgtable, hyp_va_bits, &kvm_hyp_mm_ops);
 	if (err)
 		goto out_free_pgtable;