[PATCH v3 13/21] KVM: arm64: Convert write-protect operation to generic page-table API

Will Deacon
2020-08-25T09:44:54Z

From: Quentin Perret <qperret@google.com>

Convert stage2_wp_range() to call the kvm_pgtable_stage2_wrprotect()
function of the generic page-table code instead of walking the page-table
directly.

Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kvm/mmu.c | 25 ++++---------------------
1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d3db8e00ce0a..ca2c37c91e0b 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -66,6 +66,9 @@ static bool is_iomap(unsigned long flags)
ret; \
})

+#define stage2_apply_range_resched(kvm, addr, end, fn) \
+ stage2_apply_range(kvm, addr, end, fn, true)
+
static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
@@ -1294,27 +1297,7 @@ static void stage2_wp_p4ds(struct kvm_s2_mmu *mmu, pgd_t *pgd,
static void stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
{
struct kvm *kvm = mmu->kvm;
- pgd_t *pgd;
- phys_addr_t next;
-
- pgd = mmu->pgd + stage2_pgd_index(kvm, addr);
- do {
- /*
- * 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.
- */
- cond_resched_lock(&kvm->mmu_lock);
- if (!READ_ONCE(mmu->pgd))
- break;
- next = stage2_pgd_addr_end(kvm, addr, end);
- if (stage2_pgd_present(kvm, *pgd))
- stage2_wp_p4ds(mmu, pgd, addr, next);
- } while (pgd++, addr = next, addr != end);
+ stage2_apply_range_resched(kvm, addr, end, kvm_pgtable_stage2_wrprotect);
}

/**
--
2.28.0.297.g1956fa8f8d-goog