1 files changed, 472 insertions, 0 deletions
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
new file mode 100644
index 000000000000..4ab06697bfc0
--- /dev/null
+++ b/arch/riscv/kvm/mmu.c
@@ -0,0 +1,472 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/hugetlb.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/kvm_host.h>
+#include <linux/sched/signal.h>
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_nacl.h>
+
+static void mmu_wp_memory_region(struct kvm *kvm, int slot)
+{
+	struct kvm_memslots *slots = kvm_memslots(kvm);
+	struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
+	phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
+	phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
+	struct kvm_gstage gstage;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	spin_lock(&kvm->mmu_lock);
+	kvm_riscv_gstage_wp_range(&gstage, start, end);
+	spin_unlock(&kvm->mmu_lock);
+	kvm_flush_remote_tlbs_memslot(kvm, memslot);
+}
+
+int kvm_riscv_mmu_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa,
+			  unsigned long size, bool writable, bool in_atomic)
+{
+	int ret = 0;
+	pgprot_t prot;
+	unsigned long pfn;
+	phys_addr_t addr, end;
+	struct kvm_mmu_memory_cache pcache = {
+		.gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
+		.gfp_zero = __GFP_ZERO,
+	};
+	struct kvm_gstage_mapping map;
+	struct kvm_gstage gstage;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
+	pfn = __phys_to_pfn(hpa);
+	prot = pgprot_noncached(PAGE_WRITE);
+
+	for (addr = gpa; addr < end; addr += PAGE_SIZE) {
+		map.addr = addr;
+		map.pte = pfn_pte(pfn, prot);
+		map.pte = pte_mkdirty(map.pte);
+		map.level = 0;
+
+		if (!writable)
+			map.pte = pte_wrprotect(map.pte);
+
+		ret = kvm_mmu_topup_memory_cache(&pcache, kvm_riscv_gstage_pgd_levels);
+		if (ret)
+			goto out;
+
+		spin_lock(&kvm->mmu_lock);
+		ret = kvm_riscv_gstage_set_pte(&gstage, &pcache, &map);
+		spin_unlock(&kvm->mmu_lock);
+		if (ret)
+			goto out;
+
+		pfn++;
+	}
+
+out:
+	kvm_mmu_free_memory_cache(&pcache);
+	return ret;
+}
+
+void kvm_riscv_mmu_iounmap(struct kvm *kvm, gpa_t gpa, unsigned long size)
+{
+	struct kvm_gstage gstage;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	spin_lock(&kvm->mmu_lock);
+	kvm_riscv_gstage_unmap_range(&gstage, gpa, size, false);
+	spin_unlock(&kvm->mmu_lock);
+}
+
+void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
+					     struct kvm_memory_slot *slot,
+					     gfn_t gfn_offset,
+					     unsigned long mask)
+{
+	phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
+	phys_addr_t start = (base_gfn +  __ffs(mask)) << PAGE_SHIFT;
+	phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
+	struct kvm_gstage gstage;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	kvm_riscv_gstage_wp_range(&gstage, start, end);
+}
+
+void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
+{
+}
+
+void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
+{
+}
+
+void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
+{
+}
+
+void kvm_arch_flush_shadow_all(struct kvm *kvm)
+{
+	kvm_riscv_mmu_free_pgd(kvm);
+}
+
+void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
+				   struct kvm_memory_slot *slot)
+{
+	gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
+	phys_addr_t size = slot->npages << PAGE_SHIFT;
+	struct kvm_gstage gstage;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	spin_lock(&kvm->mmu_lock);
+	kvm_riscv_gstage_unmap_range(&gstage, gpa, size, false);
+	spin_unlock(&kvm->mmu_lock);
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+				struct kvm_memory_slot *old,
+				const struct kvm_memory_slot *new,
+				enum kvm_mr_change change)
+{
+	/*
+	 * At this point memslot has been committed and there is an
+	 * allocated dirty_bitmap[], dirty pages will be tracked while
+	 * the memory slot is write protected.
+	 */
+	if (change != KVM_MR_DELETE && new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+		if (kvm_dirty_log_manual_protect_and_init_set(kvm))
+			return;
+		mmu_wp_memory_region(kvm, new->id);
+	}
+}
+
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+				const struct kvm_memory_slot *old,
+				struct kvm_memory_slot *new,
+				enum kvm_mr_change change)
+{
+	hva_t hva, reg_end, size;
+	bool writable;
+	int ret = 0;
+
+	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
+			change != KVM_MR_FLAGS_ONLY)
+		return 0;
+
+	/*
+	 * Prevent userspace from creating a memory region outside of the GPA
+	 * space addressable by the KVM guest GPA space.
+	 */
+	if ((new->base_gfn + new->npages) >=
+	    (kvm_riscv_gstage_gpa_size >> PAGE_SHIFT))
+		return -EFAULT;
+
+	hva = new->userspace_addr;
+	size = new->npages << PAGE_SHIFT;
+	reg_end = hva + size;
+	writable = !(new->flags & KVM_MEM_READONLY);
+
+	mmap_read_lock(current->mm);
+
+	/*
+	 * A memory region could potentially cover multiple VMAs, and
+	 * any holes between them, so iterate over all of them.
+	 *
+	 *     +--------------------------------------------+
+	 * +---------------+----------------+   +----------------+
+	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
+	 * +---------------+----------------+   +----------------+
+	 *     |               memory region                |
+	 *     +--------------------------------------------+
+	 */
+	do {
+		struct vm_area_struct *vma;
+		hva_t vm_end;
+
+		vma = find_vma_intersection(current->mm, hva, reg_end);
+		if (!vma)
+			break;
+
+		/*
+		 * Mapping a read-only VMA is only allowed if the
+		 * memory region is configured as read-only.
+		 */
+		if (writable && !(vma->vm_flags & VM_WRITE)) {
+			ret = -EPERM;
+			break;
+		}
+
+		/* Take the intersection of this VMA with the memory region */
+		vm_end = min(reg_end, vma->vm_end);
+
+		if (vma->vm_flags & VM_PFNMAP) {
+			/* IO region dirty page logging not allowed */
+			if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+		hva = vm_end;
+	} while (hva < reg_end);
+
+out:
+	mmap_read_unlock(current->mm);
+	return ret;
+}
+
+bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	struct kvm_gstage gstage;
+
+	if (!kvm->arch.pgd)
+		return false;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+	kvm_riscv_gstage_unmap_range(&gstage, range->start << PAGE_SHIFT,
+				     (range->end - range->start) << PAGE_SHIFT,
+				     range->may_block);
+	return false;
+}
+
+bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	pte_t *ptep;
+	u32 ptep_level = 0;
+	u64 size = (range->end - range->start) << PAGE_SHIFT;
+	struct kvm_gstage gstage;
+
+	if (!kvm->arch.pgd)
+		return false;
+
+	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+	if (!kvm_riscv_gstage_get_leaf(&gstage, range->start << PAGE_SHIFT,
+				       &ptep, &ptep_level))
+		return false;
+
+	return ptep_test_and_clear_young(NULL, 0, ptep);
+}
+
+bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
+{
+	pte_t *ptep;
+	u32 ptep_level = 0;
+	u64 size = (range->end - range->start) << PAGE_SHIFT;
+	struct kvm_gstage gstage;
+
+	if (!kvm->arch.pgd)
+		return false;
+
+	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PUD_SIZE);
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+	if (!kvm_riscv_gstage_get_leaf(&gstage, range->start << PAGE_SHIFT,
+				       &ptep, &ptep_level))
+		return false;
+
+	return pte_young(ptep_get(ptep));
+}
+
+int kvm_riscv_mmu_map(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot,
+		      gpa_t gpa, unsigned long hva, bool is_write,
+		      struct kvm_gstage_mapping *out_map)
+{
+	int ret;
+	kvm_pfn_t hfn;
+	bool writable;
+	short vma_pageshift;
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct vm_area_struct *vma;
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_mmu_memory_cache *pcache = &vcpu->arch.mmu_page_cache;
+	bool logging = (memslot->dirty_bitmap &&
+			!(memslot->flags & KVM_MEM_READONLY)) ? true : false;
+	unsigned long vma_pagesize, mmu_seq;
+	struct kvm_gstage gstage;
+	struct page *page;
+
+	gstage.kvm = kvm;
+	gstage.flags = 0;
+	gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+	gstage.pgd = kvm->arch.pgd;
+
+	/* Setup initial state of output mapping */
+	memset(out_map, 0, sizeof(*out_map));
+
+	/* We need minimum second+third level pages */
+	ret = kvm_mmu_topup_memory_cache(pcache, kvm_riscv_gstage_pgd_levels);
+	if (ret) {
+		kvm_err("Failed to topup G-stage cache\n");
+		return ret;
+	}
+
+	mmap_read_lock(current->mm);
+
+	vma = vma_lookup(current->mm, hva);
+	if (unlikely(!vma)) {
+		kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
+		mmap_read_unlock(current->mm);
+		return -EFAULT;
+	}
+
+	if (is_vm_hugetlb_page(vma))
+		vma_pageshift = huge_page_shift(hstate_vma(vma));
+	else
+		vma_pageshift = PAGE_SHIFT;
+	vma_pagesize = 1ULL << vma_pageshift;
+	if (logging || (vma->vm_flags & VM_PFNMAP))
+		vma_pagesize = PAGE_SIZE;
+
+	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
+		gfn = (gpa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
+
+	/*
+	 * Read mmu_invalidate_seq so that KVM can detect if the results of
+	 * vma_lookup() or __kvm_faultin_pfn() become stale prior to acquiring
+	 * kvm->mmu_lock.
+	 *
+	 * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs
+	 * with the smp_wmb() in kvm_mmu_invalidate_end().
+	 */
+	mmu_seq = kvm->mmu_invalidate_seq;
+	mmap_read_unlock(current->mm);
+
+	if (vma_pagesize != PUD_SIZE &&
+	    vma_pagesize != PMD_SIZE &&
+	    vma_pagesize != PAGE_SIZE) {
+		kvm_err("Invalid VMA page size 0x%lx\n", vma_pagesize);
+		return -EFAULT;
+	}
+
+	hfn = __kvm_faultin_pfn(memslot, gfn, is_write ? FOLL_WRITE : 0,
+				&writable, &page);
+	if (hfn == KVM_PFN_ERR_HWPOISON) {
+		send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva,
+				vma_pageshift, current);
+		return 0;
+	}
+	if (is_error_noslot_pfn(hfn))
+		return -EFAULT;
+
+	/*
+	 * If logging is active then we allow writable pages only
+	 * for write faults.
+	 */
+	if (logging && !is_write)
+		writable = false;
+
+	spin_lock(&kvm->mmu_lock);
+
+	if (mmu_invalidate_retry(kvm, mmu_seq))
+		goto out_unlock;
+
+	if (writable) {
+		mark_page_dirty_in_slot(kvm, memslot, gfn);
+		ret = kvm_riscv_gstage_map_page(&gstage, pcache, gpa, hfn << PAGE_SHIFT,
+						vma_pagesize, false, true, out_map);
+	} else {
+		ret = kvm_riscv_gstage_map_page(&gstage, pcache, gpa, hfn << PAGE_SHIFT,
+						vma_pagesize, true, true, out_map);
+	}
+
+	if (ret)
+		kvm_err("Failed to map in G-stage\n");
+
+out_unlock:
+	kvm_release_faultin_page(kvm, page, ret && ret != -EEXIST, writable);
+	spin_unlock(&kvm->mmu_lock);
+	return ret;
+}
+
+int kvm_riscv_mmu_alloc_pgd(struct kvm *kvm)
+{
+	struct page *pgd_page;
+
+	if (kvm->arch.pgd != NULL) {
+		kvm_err("kvm_arch already initialized?\n");
+		return -EINVAL;
+	}
+
+	pgd_page = alloc_pages(GFP_KERNEL | __GFP_ZERO,
+				get_order(kvm_riscv_gstage_pgd_size));
+	if (!pgd_page)
+		return -ENOMEM;
+	kvm->arch.pgd = page_to_virt(pgd_page);
+	kvm->arch.pgd_phys = page_to_phys(pgd_page);
+
+	return 0;
+}
+
+void kvm_riscv_mmu_free_pgd(struct kvm *kvm)
+{
+	struct kvm_gstage gstage;
+	void *pgd = NULL;
+
+	spin_lock(&kvm->mmu_lock);
+	if (kvm->arch.pgd) {
+		gstage.kvm = kvm;
+		gstage.flags = 0;
+		gstage.vmid = READ_ONCE(kvm->arch.vmid.vmid);
+		gstage.pgd = kvm->arch.pgd;
+		kvm_riscv_gstage_unmap_range(&gstage, 0UL, kvm_riscv_gstage_gpa_size, false);
+		pgd = READ_ONCE(kvm->arch.pgd);
+		kvm->arch.pgd = NULL;
+		kvm->arch.pgd_phys = 0;
+	}
+	spin_unlock(&kvm->mmu_lock);
+
+	if (pgd)
+		free_pages((unsigned long)pgd, get_order(kvm_riscv_gstage_pgd_size));
+}
+
+void kvm_riscv_mmu_update_hgatp(struct kvm_vcpu *vcpu)
+{
+	unsigned long hgatp = kvm_riscv_gstage_mode << HGATP_MODE_SHIFT;
+	struct kvm_arch *k = &vcpu->kvm->arch;
+
+	hgatp |= (READ_ONCE(k->vmid.vmid) << HGATP_VMID_SHIFT) & HGATP_VMID;
+	hgatp |= (k->pgd_phys >> PAGE_SHIFT) & HGATP_PPN;
+
+	ncsr_write(CSR_HGATP, hgatp);
+
+	if (!kvm_riscv_gstage_vmid_bits())
+		kvm_riscv_local_hfence_gvma_all();
+}