[PATCH v2 2/2] KVM: arm64: ptdump: Flush the last region
From: Wei-Lin Chang <hidden>
Date: 2026-07-24 18:54:56
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Currently the stage-2 ptdump calls note_page() at each leaf entry visit.
This simply misses the output of the last region, because note_page()
only dumps output when it detects a change in level/prot, or when the
walk enters a next marker section. The last region in the guest IPA
space with the same level/prot is not dumped since there is no change
after it.
Call note_page_flush() to dump the final region. note_page_flush()
expects ptdump_state.range[] to be initialized to the range of the
address space, so also do that.
Also change the second marker's start address to ULONG_MAX so we never
cross it. This avoids dumping redundant marker names (which are NULL),
and advancing beyond the end of the marker array.
Fixes: 7c4f73548ed1 ("KVM: arm64: Register ptdump with debugfs on guest creation")
Reported-by: Sashiko AI <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/kvmarm/20260630122758.891011F00A3A@smtp.kernel.org/ (local)
Signed-off-by: Wei-Lin Chang <redacted>
---
arch/arm64/kvm/ptdump.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/ptdump.c b/arch/arm64/kvm/ptdump.c
index c9140e22abcf..222577163d2b 100644
--- a/arch/arm64/kvm/ptdump.c
+++ b/arch/arm64/kvm/ptdump.c@@ -130,7 +130,7 @@ static struct kvm_ptdump_guest_state *kvm_ptdump_parser_create(struct kvm_s2_mmu } st->ipa_marker[0].name = "Guest IPA"; - st->ipa_marker[1].start_address = BIT(pgtable->ia_bits); + st->ipa_marker[1].start_address = ULONG_MAX; st->mmu = mmu; return st;
@@ -148,18 +148,26 @@ static int kvm_ptdump_guest_show(struct seq_file *m, void *unused) .flags = KVM_PGTABLE_WALK_LEAF, }; + guard(write_lock)(&kvm->mmu_lock); st->parser_state = (struct ptdump_pg_state) { .marker = &st->ipa_marker[0], .level = -1, .pg_level = &st->level[0], .seq = m, + .ptdump = { + .range = (struct ptdump_range[]){ + {0, BIT(mmu->pgt->ia_bits)}, + {0, 0} + } + } }; - write_lock(&kvm->mmu_lock); ret = kvm_pgtable_walk(mmu->pgt, 0, BIT(mmu->pgt->ia_bits), &walker); - write_unlock(&kvm->mmu_lock); + if (ret) + return ret; + note_page_flush(&st->parser_state.ptdump); - return ret; + return 0; } static int kvm_ptdump_guest_open(struct inode *m, struct file *file)
--
2.43.0