Convert unmap_stage2_range() to use kvm_pgtable_stage2_unmap() instead
of walking the page-table directly.
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Quentin Perret <qperret@xxxxxxxxxx>
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
---
arch/arm64/kvm/mmu.c | 62 ++++++++++++++++++++++++++------------------
1 file changed, 37 insertions(+), 25 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d8cfdd25eac5..f03d3d0af10d 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -39,6 +39,38 @@ static bool is_iomap(unsigned long flags)
return flags & KVM_S2PTE_FLAG_IS_IOMAP;
}
+/*
+ * Release kvm_mmu_lock periodically if the memory region is large. Otherwise,
+ * we may see kernel panics with CONFIG_DETECT_HUNG_TASK,
+ * CONFIG_LOCKUP_DETECTOR, CONFIG_LOCKDEP. Additionally, holding the lock too
+ * long will also starve other vCPUs. We have to also make sure that the page
+ * tables are not freed while we released the lock.
+ */
+static int stage2_apply_range(struct kvm *kvm, phys_addr_t addr,
+ phys_addr_t end,
+ int (*fn)(struct kvm_pgtable *, u64, u64),
+ bool resched)
+{
+ int ret;
+ u64 next;
+
+ do {
+ struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
+ if (!pgt)
+ return -EINVAL;
+
+ next = stage2_pgd_addr_end(kvm, addr, end);
+ ret = fn(pgt, addr, next - addr);
+ if (ret)
+ break;
+
+ if (resched && next != end)
+ cond_resched_lock(&kvm->mmu_lock);
+ } while (addr = next, addr != end);
+
+ return ret;
+}
+
static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
@@ -220,8 +252,8 @@ static inline void kvm_pgd_populate(pgd_t *pgdp, p4d_t *p4dp)
* end up writing old data to disk.
*
* This is why right after unmapping a page/section and invalidating
- * the corresponding TLBs, we call kvm_flush_dcache_p*() to make sure
- * the IO subsystem will never hit in the cache.
+ * the corresponding TLBs, we flush to make sure the IO subsystem will
+ * never hit in the cache.
*
* This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as
* we then fully enforce cacheability of RAM, no matter what the guest
@@ -344,32 +376,12 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
bool may_block)
{
struct kvm *kvm = mmu->kvm;
- pgd_t *pgd;
- phys_addr_t addr = start, end = start + size;
- phys_addr_t next;
+ phys_addr_t end = start + size;
assert_spin_locked(&kvm->mmu_lock);
WARN_ON(size & ~PAGE_MASK);
-
- pgd = mmu->pgd + stage2_pgd_index(kvm, addr);
- do {
- /*
- * Make sure the page table is still active, as another thread
- * could have possibly freed the page table, while we released
- * the lock.
- */
- if (!READ_ONCE(mmu->pgd))
- break;
- next = stage2_pgd_addr_end(kvm, addr, end);
- if (!stage2_pgd_none(kvm, *pgd))
- unmap_stage2_p4ds(mmu, pgd, addr, next);
- /*
- * If the range is too large, release the kvm->mmu_lock
- * to prevent starvation and lockup detector warnings.
- */
- if (may_block && next != end)
- cond_resched_lock(&kvm->mmu_lock);
- } while (pgd++, addr = next, addr != end);
+ WARN_ON(stage2_apply_range(kvm, start, end, kvm_pgtable_stage2_unmap,
+ may_block));
}
static void unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
--
2.28.0.618.gf4bc123cb7-goog
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