[PATCH v3] KVM: arm64: Fix protected VM fault on system with pages larger than 4K
COLD15d
From: Vincent Donnefort <hidden>
Date: 2026-09-15 09:16:31
Also in:
kvmarm
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
Just like commit 08f97454b7fa ("KVM: arm64: Fix protected mode handling
of pages larger than 4kB") fixed the boot of non-protected VMs on system
larger than 4K pages, align the fault IPA down to the page-size for
protected VMs.
To paraphrase Marc, pkvm_pgtable_stage2_map() assumes the address passed
as a parameter is aligned to the size of the intended mapping, while
HPFAR_EL2 gives the IPA minus the bottom 12 bits, regardless of the
system page size configuration.
Add a check at the start of pkvm_pgtable_stage2_map() as we do not
support !PAGE_ALIGNED arguments and ensure callers pass a page-aligned
IPA.
Fixes: ea03466e806f ("KVM: arm64: Handle aborts from protected VMs")
Signed-off-by: Vincent Donnefort <redacted>
---
arch/arm64/kvm/mmu.c | 12 +++++++-----
arch/arm64/kvm/pkvm.c | 3 +++
2 files changed, 10 insertions(+), 5 deletions(-)
Changelog:
v3:
- Fix nested case in gmem_abort() (Sashiko)
v2: https://lore.kernel.org/all/20260914075839.4019904-1-vdonnefort@google.com/ (local)
- Use gfn_to_gpa(gfn)
- Drop "phys" from the PAGE_ALIGNED check, it isn't a requirement.
- Fix gmem_abort() as well (Sashiko)
v1: https://lore.kernel.org/all/20260913173516.3122436-1-vdonnefort@google.com/ (local)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 9ba86450fe4a..e199dd339583 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c@@ -1610,6 +1610,7 @@ static int gmem_abort(const struct kvm_s2_fault_desc *s2fd) bool write_fault, exec_fault; bool perm_fault = kvm_vcpu_trap_is_permission_fault(s2fd->vcpu); enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED; + phys_addr_t ipa = ALIGN_DOWN(s2fd->fault_ipa, PAGE_SIZE); enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R; struct kvm_pgtable *pgt = s2fd->vcpu->arch.hw_mmu->pgt; unsigned long mmu_seq;
@@ -1672,12 +1673,12 @@ static int gmem_abort(const struct kvm_s2_fault_desc *s2fd) * PTE, which will be preserved. */ prot &= ~KVM_NV_GUEST_MAP_SZ; - ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, s2fd->fault_ipa, + ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, ipa, prot, flags); } else { - ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, s2fd->fault_ipa, PAGE_SIZE, - __pfn_to_phys(pfn), prot, - memcache, flags); + ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, ipa, PAGE_SIZE, + __pfn_to_phys(pfn), + prot, memcache, flags); } out_unlock:
@@ -1710,6 +1711,7 @@ static int pkvm_mem_abort(const struct kvm_s2_fault_desc *s2fd) unsigned int flags = FOLL_HWPOISON | FOLL_LONGTERM | FOLL_WRITE; struct kvm_vcpu *vcpu = s2fd->vcpu; struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt; + gfn_t gfn = gpa_to_gfn(s2fd->fault_ipa); struct mm_struct *mm = current->mm; struct kvm *kvm = vcpu->kvm; void *hyp_memcache;
@@ -1756,7 +1758,7 @@ static int pkvm_mem_abort(const struct kvm_s2_fault_desc *s2fd) } write_lock(&kvm->mmu_lock); - ret = pkvm_pgtable_stage2_map(pgt, s2fd->fault_ipa, PAGE_SIZE, + ret = pkvm_pgtable_stage2_map(pgt, gfn_to_gpa(gfn), PAGE_SIZE, page_to_phys(page), KVM_PGTABLE_PROT_RWX, hyp_memcache, 0); write_unlock(&kvm->mmu_lock);
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 8e4c6e4bec12..b7340c430ed6 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c@@ -414,6 +414,9 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 end = addr + size; int ret; + if (!PAGE_ALIGNED(addr | size)) + return -EINVAL; + lockdep_assert_held_write(&kvm->mmu_lock); mapping = pkvm_mapping_iter_first(&pgt->pkvm_mappings, addr, end - 1);
base-commit: df2908090cda368b01ff43709f51890076c56157 -- 2.55.0.1032.g73a4cd73de-goog