From: Will Deacon <will@kernel.org>
To: kvmarm@lists.cs.columbia.edu
Cc: kernel-team@android.com, Marc Zyngier <maz@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 08/20] KVM: arm64: Convert unmap_stage2_range() to generic page-table API
Date: Thu, 30 Jul 2020 16:33:54 +0100 [thread overview]
Message-ID: <20200730153406.25136-9-will@kernel.org> (raw)
In-Reply-To: <20200730153406.25136-1-will@kernel.org>
Convert unmap_stage2_range() to use kvm_pgtable_stage2_unmap() instead
of walking the page-table directly.
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kvm/mmu.c | 58 +++++++++++++++++++++++++-------------------
1 file changed, 33 insertions(+), 25 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index f6b7220412af..d2ce44183b98 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -39,6 +39,32 @@ 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.
+ */
+#define stage2_apply_range_resched(kvm, addr, end, fn) \
+({ \
+ int ret; \
+ struct kvm *__kvm = (kvm); \
+ u64 next, __addr = (addr), __end = (end); \
+ do { \
+ void *cookie = __kvm->arch.mmu.pgt_cookie; \
+ if (!cookie) \
+ break; \
+ next = stage2_pgd_addr_end(__kvm, __addr, __end); \
+ ret = fn(cookie, __addr, next - __addr); \
+ if (ret) \
+ break; \
+ if (next != __end) \
+ cond_resched_lock(&__kvm->mmu_lock); \
+ } while (__addr = next, __addr != __end); \
+ ret; \
+})
+
static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
@@ -256,8 +282,8 @@ 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
@@ -375,36 +401,18 @@ static void unmap_stage2_p4ds(struct kvm_s2_mmu *mmu, pgd_t *pgd,
* be called while holding mmu_lock (unless for freeing the stage2 pgd before
* destroying the VM), otherwise another faulting VCPU may come in and mess
* with things behind our backs.
+ *
+ * Return: 0 on success, negative error code on failure.
*/
static void unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
{
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 (next != end)
- cond_resched_lock(&kvm->mmu_lock);
- } while (pgd++, addr = next, addr != end);
+ WARN_ON(stage2_apply_range_resched(kvm, start, end,
+ kvm_pgtable_stage2_unmap));
}
static void stage2_flush_ptes(struct kvm_s2_mmu *mmu, pmd_t *pmd,
--
2.28.0.rc0.142.g3c755180ce-goog
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next prev parent reply other threads:[~2020-07-30 15:34 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 15:33 [PATCH 00/20] KVM: arm64: Rewrite page-table code and fault handling Will Deacon
2020-07-30 15:33 ` [PATCH 01/20] KVM: arm64: Add stand-alone page-table walker infrastructure Will Deacon
2020-07-30 15:33 ` [PATCH 02/20] KVM: arm64: Add support for creating kernel-agnostic stage-1 page tables Will Deacon
2020-07-31 8:14 ` Quentin Perret
2020-07-31 8:19 ` Quentin Perret
2020-07-31 8:22 ` Will Deacon
2020-07-31 8:36 ` Quentin Perret
2020-07-31 9:06 ` Quentin Perret
2020-07-30 15:33 ` [PATCH 03/20] KVM: arm64: Use generic allocator for hyp stage-1 page-tables Will Deacon
2020-07-30 15:33 ` [PATCH 04/20] KVM: arm64: Add support for creating kernel-agnostic stage-2 page tables Will Deacon
2020-07-30 15:33 ` [PATCH 05/20] KVM: arm64: Add support for stage-2 map()/unmap() in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 06/20] KVM: arm64: Convert kvm_phys_addr_ioremap() to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 07/20] KVM: arm64: Convert kvm_set_spte_hva() " Will Deacon
2020-07-30 15:33 ` Will Deacon [this message]
2020-07-30 15:33 ` [PATCH 09/20] KVM: arm64: Add support for stage-2 page-aging in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 10/20] KVM: arm64: Convert page-aging and access faults to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 11/20] KVM: arm64: Add support for stage-2 write-protect in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 12/20] KVM: arm64: Convert write-protect operation to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 13/20] KVM: arm64: Add support for stage-2 cache flushing in generic page-table Will Deacon
2020-07-30 15:34 ` [PATCH 14/20] KVM: arm64: Convert memslot cache-flushing code to generic page-table API Will Deacon
2020-07-30 15:34 ` [PATCH 15/20] KVM: arm64: Add support for relaxing stage-2 perms in generic page-table code Will Deacon
2020-07-30 15:34 ` [PATCH 16/20] KVM: arm64: Convert user_mem_abort() to generic page-table API Will Deacon
2020-07-30 15:34 ` [PATCH 17/20] KVM: arm64: Check the cookie instead of the pgd when modifying page-table Will Deacon
2020-07-30 15:34 ` [PATCH 18/20] KVM: arm64: Remove unused page-table code Will Deacon
2020-07-30 15:34 ` [PATCH 19/20] KVM: arm64: Remove unused 'pgd' field from 'struct kvm_s2_mmu' Will Deacon
2020-07-30 15:34 ` [PATCH 20/20] KVM: arm64: Don't constrain maximum IPA size based on host configuration Will Deacon
2020-08-03 8:17 ` [PATCH 00/20] KVM: arm64: Rewrite page-table code and fault handling Andrew Jones
2020-08-03 17:12 ` Quentin Perret
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