The generic page-table walker is pretty useless as it stands, because it
doesn't understand enough to allocate anything. Teach it about stage-1
page-tables, and hook up an API for allocating these for the hypervisor
at EL2.
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Quentin Perret <qperret@xxxxxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_pgtable.h | 33 ++++++
arch/arm64/kvm/pgtable.c | 145 +++++++++++++++++++++++++++
2 files changed, 178 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index c1679c1a9a49..5be09ac3efa3 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -61,6 +61,39 @@ struct kvm_pgtable_walker {
const enum kvm_pgtable_walk_flags flags;
};
+/**
+ * kvm_pgtable_hyp_alloc_cookie() - Allocate a hypervisor stage-1 page-table.
+ * @va_bits: Maximum virtual address bits.
+ *
+ * Return: An opaque cookie which can be used to manipulate the page-table.
+ */
+void *kvm_pgtable_hyp_alloc_cookie(u32 va_bits);
+
+/**
+ * kvm_pgtable_hyp_free_cookie() - Free an unused hypervisor stage-1 page-table.
+ * @cookie: Opaque cookie allocated by kvm_pgtable_hyp_alloc_cookie().
+ *
+ * The page-table is assumed to be unreachable by any hardware walkers prior
+ * to freeing and therefore no TLB invalidation is performed.
+ */
+void kvm_pgtable_hyp_free_cookie(void *cookie);
+
+/**
+ * kvm_pgtable_hyp_map() - Install a mapping in a hypervisor stage-1 page-table.
+ * @cookie: Opaque cookie allocated by kvm_pgtable_hyp_alloc_cookie().
+ * @addr: Virtual address at which to place the mapping.
+ * @size: Size of the mapping.
+ * @phys: Physical address of the memory to map.
+ * @prot: Permissions and attributes for the mapping.
+ *
+ * If device attributes are not explicitly requested in @prot, then the
+ * mapping will be normal, cacheable.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int kvm_pgtable_hyp_map(void *cookie, u64 addr, u64 size, u64 phys,
+ enum kvm_pgtable_prot prot);
+
/**
* kvm_pgtable_get_pgd_phys() - Get physical pgd pointer for a page-table.
* @cookie: Opaque cookie allocated by kvm_pgtable_*_alloc_cookie().
diff --git a/arch/arm64/kvm/pgtable.c b/arch/arm64/kvm/pgtable.c
index 298620cbd67a..b148c76f8b79 100644
--- a/arch/arm64/kvm/pgtable.c
+++ b/arch/arm64/kvm/pgtable.c
@@ -24,8 +24,18 @@
#define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2)
+#define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2)
+#define KVM_PTE_LEAF_ATTR_LO_S1_AP GENMASK(7, 6)
+#define KVM_PTE_LEAF_ATTR_LO_S1_AP_RO 3
+#define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW 1
+#define KVM_PTE_LEAF_ATTR_LO_S1_SH GENMASK(9, 8)
+#define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS 3
+#define KVM_PTE_LEAF_ATTR_LO_S1_AF BIT(10)
+
#define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 51)
+#define KVM_PTE_LEAF_ATTR_HI_S1_XN BIT(54)
+
struct kvm_pgtable {
struct kvm_s2_mmu *mmu;
@@ -293,6 +303,141 @@ int kvm_pgtable_walk(void *cookie, u64 addr, u64 size,
return _kvm_pgtable_walk(&walk_data);
}
+struct hyp_map_data {
+ u64 phys;
+ kvm_pte_t attr;
+};
+
+static int hyp_map_set_prot_attr(enum kvm_pgtable_prot prot,
+ struct hyp_map_data *data)
+{
+ bool device = prot & KVM_PGTABLE_PROT_DEVICE;
+ u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL;
+ kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype);
+ u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS;
+ u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW :
+ KVM_PTE_LEAF_ATTR_LO_S1_AP_RO;
+
+ if (!(prot & KVM_PGTABLE_PROT_R))
+ return -EINVAL;
+
+ if (prot & KVM_PGTABLE_PROT_X) {
+ if (prot & KVM_PGTABLE_PROT_W)
+ return -EINVAL;
+
+ if (device)
+ return -EINVAL;
+ } else {
+ attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN;
+ }
+
+ attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap);
+ attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh);
+ attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF;
+ data->attr = attr;
+ return 0;
+}
+
+static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level,
+ kvm_pte_t *ptep, struct hyp_map_data *data)
+{
+ u64 granule = kvm_granule_size(level), phys = data->phys;
+
+ if (!kvm_block_mapping_supported(addr, end, phys, level))
+ return false;
+
+ WARN_ON(!kvm_set_valid_leaf_pte(ptep, phys, data->attr, level));
+ data->phys += granule;
+ return true;
+}
+
+static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
+ enum kvm_pgtable_walk_flags flag, void * const arg)
+{
+ kvm_pte_t *childp;
+
+ if (hyp_map_walker_try_leaf(addr, end, level, ptep, arg))
+ return 0;
+
+ if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1))
+ return -EINVAL;
+
+ childp = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL);
+ if (!childp) {
+ kvm_err("Failed to allocate page-table page\n");
+ return -ENOMEM;
+ }
+
+ kvm_set_table_pte(ptep, childp);
+ return 0;
+}
+
+int kvm_pgtable_hyp_map(void *cookie, u64 addr, u64 size, u64 phys,
+ enum kvm_pgtable_prot prot)
+{
+ int ret;
+ struct hyp_map_data map_data = {
+ .phys = ALIGN_DOWN(phys, PAGE_SIZE),
+ };
+ struct kvm_pgtable_walker walker = {
+ .cb = hyp_map_walker,
+ .flags = KVM_PGTABLE_WALK_LEAF,
+ .arg = &map_data,
+ };
+
+ ret = hyp_map_set_prot_attr(prot, &map_data);
+ if (ret)
+ return ret;
+
+ ret = kvm_pgtable_walk(cookie, addr, size, &walker);
+ dsb(ishst);
+ isb();
+ return ret;
+}
+
+void *kvm_pgtable_hyp_alloc_cookie(u32 va_bits)
+{
+ struct kvm_pgtable *pgt = kzalloc(sizeof(*pgt), GFP_KERNEL);
+
+ if (!pgt)
+ return NULL;
+
+ pgt->ia_bits = va_bits;
+ pgt->start_level = kvm_start_level(va_bits);
+
+ pgt->pgd = (kvm_pte_t *)get_zeroed_page(GFP_KERNEL);
+ if (!pgt->pgd) {
+ kfree(pgt);
+ pgt = NULL;
+ }
+
+ return pgt;
+}
+
+static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
+ enum kvm_pgtable_walk_flags flag, void * const arg)
+{
+ free_page((unsigned long)kvm_pte_follow(*ptep));
+ return 0;
+}
+
+void kvm_pgtable_hyp_free_cookie(void *cookie)
+{
+ size_t pgd_sz;
+ struct kvm_pgtable *pgt = cookie;
+ struct kvm_pgtable_walker walker = {
+ .cb = hyp_free_walker,
+ .flags = KVM_PGTABLE_WALK_TABLE_POST,
+ };
+
+ if (kvm_pgtable_walk(cookie, 0, BIT(pgt->ia_bits), &walker))
+ kvm_err("Failed to free page-table pages\n");
+
+ pgd_sz = kvm_pgd_pages(pgt) * PAGE_SIZE;
+ free_pages_exact(pgt->pgd, pgd_sz);
+ kfree(pgt);
+}
+
u64 kvm_pgtable_get_pgd_phys(void *cookie)
{
struct kvm_pgtable *pgt = cookie;
--
2.28.0.rc0.142.g3c755180ce-goog
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