[PATCH v5 4/4] KVM: arm64: Initialize the ptdump parser with stage-2 attributes

[Sebastian Ene]

Define a set of attributes used by the ptdump parser to display the
properties of a guest memory region covered by a pagetable descriptor.
Build a description of the pagetable levels and initialize the parser
with this configuration.

Signed-off-by: Sebastian Ene <sebastianene at google.com>
---
 arch/arm64/kvm/ptdump.c | 156 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)

diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index a4e984da8aa7..60725d46f17b 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c
@@ -14,6 +14,69 @@
 #include <kvm_ptdump.h>
 
 
+#define ADDR_MARKER_LEN		(2)
+#define MARKER_MSG_LEN		(32)
+
+static const struct prot_bits stage2_pte_bits[] = {
+	{
+		.mask	= PTE_VALID,
+		.val	= PTE_VALID,
+		.set	= " ",
+		.clear	= "F",
+	}, {
+		.mask	= KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID,
+		.val	= KVM_PTE_LEAF_ATTR_HI_S2_XN | PTE_VALID,
+		.set	= "XN",
+		.clear	= "  ",
+	}, {
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | PTE_VALID,
+		.set	= "R",
+		.clear	= " ",
+	}, {
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | PTE_VALID,
+		.set	= "W",
+		.clear	= " ",
+	}, {
+		.mask	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
+		.val	= KVM_PTE_LEAF_ATTR_LO_S2_AF | PTE_VALID,
+		.set	= "AF",
+		.clear	= "  ",
+	}, {
+		.mask	= PTE_NG,
+		.val	= PTE_NG,
+		.set	= "FnXS",
+		.clear	= "  ",
+	}, {
+		.mask	= PTE_CONT | PTE_VALID,
+		.val	= PTE_CONT | PTE_VALID,
+		.set	= "CON",
+		.clear	= "   ",
+	}, {
+		.mask	= PTE_TABLE_BIT,
+		.val	= PTE_TABLE_BIT,
+		.set	= "   ",
+		.clear	= "BLK",
+	}, {
+		.mask	= KVM_PGTABLE_PROT_SW0,
+		.val	= KVM_PGTABLE_PROT_SW0,
+		.set	= "SW0", /* PKVM_PAGE_SHARED_OWNED */
+	}, {
+		.mask   = KVM_PGTABLE_PROT_SW1,
+		.val	= KVM_PGTABLE_PROT_SW1,
+		.set	= "SW1", /* PKVM_PAGE_SHARED_BORROWED */
+	}, {
+		.mask	= KVM_PGTABLE_PROT_SW2,
+		.val	= KVM_PGTABLE_PROT_SW2,
+		.set	= "SW2",
+	}, {
+		.mask   = KVM_PGTABLE_PROT_SW3,
+		.val	= KVM_PGTABLE_PROT_SW3,
+		.set	= "SW3",
+	},
+};
+
 static int kvm_ptdump_guest_open(struct inode *inode, struct file *file);
 static int kvm_ptdump_guest_show(struct seq_file *m, void *);
 
@@ -52,6 +115,94 @@ static int kvm_ptdump_show_common(struct seq_file *m,
 	return kvm_pgtable_walk(pgtable, 0, BIT(pgtable->ia_bits), &walker);
 }
 
+static void kvm_ptdump_build_levels(struct pg_level *level, u32 start_lvl)
+{
+	static const char * const level_names[] = {"PGD", "PUD", "PMD", "PTE"};
+	u32 i = 0;
+	u64 mask_lvl = 0;
+
+	if (start_lvl > 2) {
+		pr_err("invalid start_lvl %u\n", start_lvl);
+		return;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(stage2_pte_bits); i++)
+		mask_lvl |= stage2_pte_bits[i].mask;
+
+	for (i = start_lvl; i <= KVM_PGTABLE_LAST_LEVEL; i++) {
+		level[i].name = level_names[i];
+		level[i].num = ARRAY_SIZE(stage2_pte_bits);
+		level[i].bits = stage2_pte_bits;
+		level[i].mask = mask_lvl;
+	}
+
+	if (start_lvl > 0)
+		level[start_lvl].name = level_names[0];
+}
+
+static int kvm_ptdump_parser_init(struct pg_state *st,
+				  struct kvm_pgtable *pgtable,
+				  struct seq_file *m)
+{
+	struct addr_marker *ipa_addr_marker;
+	char *marker_msg;
+	struct pg_level *level_descr;
+	struct ptdump_range *range;
+
+	ipa_addr_marker = kzalloc(sizeof(struct addr_marker) * ADDR_MARKER_LEN,
+				  GFP_KERNEL_ACCOUNT);
+	if (!ipa_addr_marker)
+		return -ENOMEM;
+
+	marker_msg = kzalloc(MARKER_MSG_LEN, GFP_KERNEL_ACCOUNT);
+	if (!marker_msg)
+		goto free_with_marker;
+
+	level_descr = kzalloc(sizeof(struct pg_level) * (KVM_PGTABLE_LAST_LEVEL + 1),
+			      GFP_KERNEL_ACCOUNT);
+	if (!level_descr)
+		goto free_with_msg;
+
+	range = kzalloc(sizeof(struct ptdump_range) * ADDR_MARKER_LEN,
+			GFP_KERNEL_ACCOUNT);
+	if (!range)
+		goto free_with_level;
+
+	kvm_ptdump_build_levels(level_descr, pgtable->start_level);
+
+	snprintf(marker_msg, MARKER_MSG_LEN, "IPA bits %2u start lvl %1d",
+		 pgtable->ia_bits, pgtable->start_level);
+
+	ipa_addr_marker[0].name = marker_msg;
+	ipa_addr_marker[1].start_address = BIT(pgtable->ia_bits);
+	range[0].end = BIT(pgtable->ia_bits);
+
+	st->seq = m;
+	st->marker = ipa_addr_marker;
+	st->level = -1,
+	st->pg_level = level_descr,
+	st->ptdump.range = range;
+	return 0;
+
+free_with_level:
+	kfree(level_descr);
+free_with_msg:
+	kfree(marker_msg);
+free_with_marker:
+	kfree(ipa_addr_marker);
+	return -ENOMEM;
+}
+
+static void kvm_ptdump_parser_teardown(struct pg_state *st)
+{
+	const struct addr_marker *ipa_addr_marker = st->marker;
+
+	kfree(ipa_addr_marker[0].name);
+	kfree(ipa_addr_marker);
+	kfree(st->pg_level);
+	kfree(st->ptdump.range);
+}
+
 static int kvm_ptdump_guest_show(struct seq_file *m, void *)
 {
 	struct kvm *guest_kvm = m->private;
@@ -59,10 +210,15 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *)
 	struct pg_state parser_state = {0};
 	int ret;
 
+	ret = kvm_ptdump_parser_init(&parser_state, mmu->pgt, m);
+	if (ret)
+		return ret;
+
 	write_lock(&guest_kvm->mmu_lock);
 	ret = kvm_ptdump_show_common(m, mmu->pgt, &parser_state);
 	write_unlock(&guest_kvm->mmu_lock);
 
+	kvm_ptdump_parser_teardown(&parser_state);
 	return ret;
 }
 
-- 
2.43.0.594.gd9cf4e227d-goog