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KVM: arm64: Convert unmap_stage2_range() to generic page-table API

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Convert unmap_stage2_range() to use kvm_pgtable_stage2_unmap() instead
of walking the page-table directly.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20200911132529.19844-10-will@kernel.org
This commit is contained in:
Will Deacon 2020-09-11 14:25:17 +01:00 committed by Marc Zyngier
parent e9edb17ae0
commit 52bae936f0
1 changed files with 37 additions and 25 deletions
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62
arch/arm64/kvm/mmu.c
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@ -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)