- Support write protection of entire VM address space
- Split pmds section in migration mode
- Write protect dirty pages on Dirty log read
Signed-off-by: Mario Smarduch <m.smarduch@xxxxxxxxxxx>
---
arch/arm/kvm/mmu.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 156 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 7789857..502e776 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -56,6 +56,13 @@ static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
}
+void kvm_tlb_flush_vmid(struct kvm *kvm)
+{
+ phys_addr_t x;
+ /* based on function description 2nd argument is irrelevent */
+ kvm_tlb_flush_vmid_ipa(kvm, x);
+}
+
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
int min, int max)
{
@@ -639,6 +646,143 @@ static bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap)
return false;
}
+/*
+ * Called when QEMU retrieves the dirty log and write protects dirty pages
+ * for next QEMU call to retrieve the dirty logn
+ */
+void kvm_mmu_write_protect_pt_masked(struct kvm *kvm,
+ struct kvm_memory_slot *slot,
+ gfn_t gfn_offset, unsigned long mask)
+{
+ phys_addr_t ipa;
+ pgd_t *pgdp = kvm->arch.pgd, *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte, new_pte;
+
+ while (mask) {
+ ipa = (slot->base_gfn + gfn_offset + __ffs(mask)) << PAGE_SHIFT;
+ pgd = pgdp + pgd_index(ipa);
+ if (!pgd_present(*pgd))
+ goto update_mask;
+ pud = pud_offset(pgd, ipa);
+ if (!pud_present(*pud))
+ goto update_mask;
+ pmd = pmd_offset(pud, ipa);
+ if (!pmd_present(*pmd))
+ goto update_mask;
+ pte = pte_offset_kernel(pmd, ipa);
+ if (!pte_present(*pte))
+ goto update_mask;
+ if ((*pte & L_PTE_S2_RDWR) == L_PTE_S2_RDONLY)
+ goto update_mask;
+ new_pte = pfn_pte(pte_pfn(*pte), PAGE_S2);
+ *pte = new_pte;
+update_mask:
+ mask &= mask - 1;
+ }
+}
+
+/*
+ * In migration splits PMDs into PTEs to keep track of dirty pages. Without
+ * spliting light execution prevents migration.
+ */
+bool split_pmd(struct kvm *kvm, pmd_t *pmd, u64 addr)
+{
+ struct page *page;
+ pfn_t pfn = pmd_pfn(*pmd);
+ pte_t *pte, new_pte;
+ int i;
+
+ page = alloc_page(GFP_KERNEL);
+ if (page == NULL)
+ return false;
+
+ pte = page_address(page);
+ for (i = 0; i < PMD_SIZE/PAGE_SIZE; i++) {
+ new_pte = pfn_pte(pfn+i, PAGE_S2);
+ pte[i] = new_pte;
+ }
+ kvm_clean_pte(pte);
+ pmd_populate_kernel(NULL, pmd, pte);
+
+ /*
+ * flush the whole TLB for VM relying on hardware broadcast
+ */
+ kvm_tlb_flush_vmid(kvm);
+ get_page(virt_to_page(pte));
+ return true;
+}
+
+/*
+ * Called from QEMU when migration dirty logging is started. Write the protect
+ * current set. Future faults writes are tracked through WP of when dirty log
+ * log.
+ */
+
+void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte, new_pte;
+ pgd_t *pgdp = kvm->arch.pgd;
+ struct kvm_memory_slot *memslot = id_to_memslot(kvm->memslots, slot);
+ u64 start = memslot->base_gfn << PAGE_SHIFT;
+ u64 end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
+ u64 addr = start, addr1;
+
+ spin_lock(&kvm->mmu_lock);
+ kvm->arch.migration_in_progress = true;
+ while (addr < end) {
+ if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+ kvm_tlb_flush_vmid(kvm);
+ cond_resched_lock(&kvm->mmu_lock);
+ }
+
+ pgd = pgdp + pgd_index(addr);
+ if (!pgd_present(*pgd)) {
+ addr = pgd_addr_end(addr, end);
+ continue;
+ }
+
+ pud = pud_offset(pgd, addr);
+ if (pud_huge(*pud) || !pud_present(*pud)) {
+ addr = pud_addr_end(addr, end);
+ continue;
+ }
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd)) {
+ addr = pmd_addr_end(addr, end);
+ continue;
+ }
+
+ if (kvm_pmd_huge(*pmd)) {
+ if (!split_pmd(kvm, pmd, addr)) {
+ kvm->arch.migration_in_progress = false;
+ return;
+ }
+ addr = pmd_addr_end(addr, end);
+ continue;
+ }
+
+ pte = pte_offset_kernel(pmd, addr);
+ addr1 = addr;
+ addr += PAGE_SIZE;
+ if (!pte_present(*pte))
+ continue;
+
+ if ((*pte & L_PTE_S2_RDWR) == L_PTE_S2_RDONLY)
+ continue;
+
+ new_pte = pfn_pte(pte_pfn(*pte), PAGE_S2);
+ *pte = new_pte;
+ }
+ kvm_tlb_flush_vmid(kvm);
+ spin_unlock(&kvm->mmu_lock);
+}
+
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_memory_slot *memslot,
unsigned long fault_status)
@@ -652,6 +796,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
struct vm_area_struct *vma;
pfn_t pfn;
+ bool migration_active = vcpu->kvm->arch.migration_in_progress;
write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu));
if (fault_status == FSC_PERM && !write_fault) {
@@ -705,10 +850,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
spin_lock(&kvm->mmu_lock);
if (mmu_notifier_retry(kvm, mmu_seq))
goto out_unlock;
- if (!hugetlb && !force_pte)
+ /* During migration don't rebuild huge pages */
+ if (!hugetlb && !force_pte && !migration_active)
hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa);
- if (hugetlb) {
+ if (!migration_active && hugetlb) {
pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2);
new_pmd = pmd_mkhuge(new_pmd);
if (writable) {
@@ -720,6 +866,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
} else {
pte_t new_pte = pfn_pte(pfn, PAGE_S2);
if (writable) {
+ if (migration_active && hugetlb) {
+ /* get back pfn from fault_ipa */
+ pfn += (fault_ipa >> PAGE_SHIFT) &
+ ((1 << (PMD_SHIFT - PAGE_SHIFT))-1);
+ new_pte = pfn_pte(pfn, PAGE_S2);
+ }
kvm_set_s2pte_writable(&new_pte);
kvm_set_pfn_dirty(pfn);
}
@@ -727,6 +879,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false);
}
+ if (writable)
+ mark_page_dirty(kvm, gfn);
out_unlock:
spin_unlock(&kvm->mmu_lock);
--
1.7.9.5
--
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