diff options
| -rw-r--r-- | arch/arm64/kvm/mmu.c | 62 |
1 files 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) |