This patch implements all required functions for programming
the stage2 page table for each Guest/VM.

At high-level, the flow of stage2 related functions is similar
from KVM ARM/ARM64 implementation but the stage2 page table
format is quite different for KVM RISC-V.

[jiangyifei: stage2 dirty log support]
Signed-off-by: Yifei Jiang <jiangyi...@huawei.com>
Signed-off-by: Anup Patel <anup.pa...@wdc.com>
Acked-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
---
 arch/riscv/include/asm/kvm_host.h     |  12 +
 arch/riscv/include/asm/pgtable-bits.h |   1 +
 arch/riscv/kvm/Kconfig                |   1 +
 arch/riscv/kvm/main.c                 |  19 +
 arch/riscv/kvm/mmu.c                  | 650 +++++++++++++++++++++++++-
 arch/riscv/kvm/vm.c                   |   6 -
 6 files changed, 673 insertions(+), 16 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h 
b/arch/riscv/include/asm/kvm_host.h
index 8612d8b35322..f80c394312b8 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -75,6 +75,13 @@ struct kvm_mmio_decode {
        int return_handled;
 };
 
+#define KVM_MMU_PAGE_CACHE_NR_OBJS     32
+
+struct kvm_mmu_page_cache {
+       int nobjs;
+       void *objects[KVM_MMU_PAGE_CACHE_NR_OBJS];
+};
+
 struct kvm_cpu_trap {
        unsigned long sepc;
        unsigned long scause;
@@ -176,6 +183,9 @@ struct kvm_vcpu_arch {
        /* MMIO instruction details */
        struct kvm_mmio_decode mmio_decode;
 
+       /* Cache pages needed to program page tables with spinlock held */
+       struct kvm_mmu_page_cache mmu_page_cache;
+
        /* VCPU power-off state */
        bool power_off;
 
@@ -204,6 +214,8 @@ void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
 int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu);
+void kvm_riscv_stage2_mode_detect(void);
+unsigned long kvm_riscv_stage2_mode(void);
 
 void kvm_riscv_stage2_vmid_detect(void);
 unsigned long kvm_riscv_stage2_vmid_bits(void);
diff --git a/arch/riscv/include/asm/pgtable-bits.h 
b/arch/riscv/include/asm/pgtable-bits.h
index bbaeb5d35842..be49d62fcc2b 100644
--- a/arch/riscv/include/asm/pgtable-bits.h
+++ b/arch/riscv/include/asm/pgtable-bits.h
@@ -26,6 +26,7 @@
 
 #define _PAGE_SPECIAL   _PAGE_SOFT
 #define _PAGE_TABLE     _PAGE_PRESENT
+#define _PAGE_LEAF      (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
 
 /*
  * _PAGE_PROT_NONE is set on not-present pages (and ignored by the hardware) to
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index b42979f84042..633063edaee8 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -23,6 +23,7 @@ config KVM
        select PREEMPT_NOTIFIERS
        select ANON_INODES
        select KVM_MMIO
+       select KVM_GENERIC_DIRTYLOG_READ_PROTECT
        select HAVE_KVM_VCPU_ASYNC_IOCTL
        select HAVE_KVM_EVENTFD
        select SRCU
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index 49a4941e3838..421ecf4e6360 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -64,6 +64,8 @@ void kvm_arch_hardware_disable(void)
 
 int kvm_arch_init(void *opaque)
 {
+       const char *str;
+
        if (!riscv_isa_extension_available(NULL, h)) {
                kvm_info("hypervisor extension not available\n");
                return -ENODEV;
@@ -79,10 +81,27 @@ int kvm_arch_init(void *opaque)
                return -ENODEV;
        }
 
+       kvm_riscv_stage2_mode_detect();
+
        kvm_riscv_stage2_vmid_detect();
 
        kvm_info("hypervisor extension available\n");
 
+       switch (kvm_riscv_stage2_mode()) {
+       case HGATP_MODE_SV32X4:
+               str = "Sv32x4";
+               break;
+       case HGATP_MODE_SV39X4:
+               str = "Sv39x4";
+               break;
+       case HGATP_MODE_SV48X4:
+               str = "Sv48x4";
+               break;
+       default:
+               return -ENODEV;
+       }
+       kvm_info("using %s G-stage page table format\n", str);
+
        kvm_info("VMID %ld bits available\n", kvm_riscv_stage2_vmid_bits());
 
        return 0;
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 8ec10ef861e7..4c533a41b887 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -17,11 +17,415 @@
 #include <linux/sched/signal.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
+#include <asm/sbi.h>
+
+#ifdef CONFIG_64BIT
+static unsigned long stage2_mode = (HGATP_MODE_SV39X4 << HGATP_MODE_SHIFT);
+static unsigned long stage2_pgd_levels = 3;
+#define stage2_index_bits      9
+#else
+static unsigned long stage2_mode = (HGATP_MODE_SV32X4 << HGATP_MODE_SHIFT);
+static unsigned long stage2_pgd_levels = 2;
+#define stage2_index_bits      10
+#endif
+
+#define stage2_pgd_xbits       2
+#define stage2_pgd_size        (1UL << (HGATP_PAGE_SHIFT + stage2_pgd_xbits))
+#define stage2_gpa_bits        (HGATP_PAGE_SHIFT + \
+                        (stage2_pgd_levels * stage2_index_bits) + \
+                        stage2_pgd_xbits)
+#define stage2_gpa_size        ((gpa_t)(1ULL << stage2_gpa_bits))
+
+static inline unsigned long stage2_pte_index(gpa_t addr, u32 level)
+{
+       unsigned long mask;
+       unsigned long shift = HGATP_PAGE_SHIFT + (stage2_index_bits * level);
+
+       if (level == (stage2_pgd_levels - 1))
+               mask = (PTRS_PER_PTE * (1UL << stage2_pgd_xbits)) - 1;
+       else
+               mask = PTRS_PER_PTE - 1;
+
+       return (addr >> shift) & mask;
+}
+
+static inline unsigned long stage2_pte_page_vaddr(pte_t pte)
+{
+       return (unsigned long)pfn_to_virt(pte_val(pte) >> _PAGE_PFN_SHIFT);
+}
+
+static int stage2_page_size_to_level(unsigned long page_size, u32 *out_level)
+{
+       u32 i;
+       unsigned long psz = 1UL << 12;
+
+       for (i = 0; i < stage2_pgd_levels; i++) {
+               if (page_size == (psz << (i * stage2_index_bits))) {
+                       *out_level = i;
+                       return 0;
+               }
+       }
+
+       return -EINVAL;
+}
+
+static int stage2_level_to_page_size(u32 level, unsigned long *out_pgsize)
+{
+       if (stage2_pgd_levels < level)
+               return -EINVAL;
+
+       *out_pgsize = 1UL << (12 + (level * stage2_index_bits));
+
+       return 0;
+}
+
+static int stage2_cache_topup(struct kvm_mmu_page_cache *pcache,
+                             int min, int max)
+{
+       void *page;
+
+       BUG_ON(max > KVM_MMU_PAGE_CACHE_NR_OBJS);
+       if (pcache->nobjs >= min)
+               return 0;
+       while (pcache->nobjs < max) {
+               page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+               if (!page)
+                       return -ENOMEM;
+               pcache->objects[pcache->nobjs++] = page;
+       }
+
+       return 0;
+}
+
+static void stage2_cache_flush(struct kvm_mmu_page_cache *pcache)
+{
+       while (pcache && pcache->nobjs)
+               free_page((unsigned long)pcache->objects[--pcache->nobjs]);
+}
+
+static void *stage2_cache_alloc(struct kvm_mmu_page_cache *pcache)
+{
+       void *p;
+
+       if (!pcache)
+               return NULL;
+
+       BUG_ON(!pcache->nobjs);
+       p = pcache->objects[--pcache->nobjs];
+
+       return p;
+}
+
+static bool stage2_get_leaf_entry(struct kvm *kvm, gpa_t addr,
+                                 pte_t **ptepp, u32 *ptep_level)
+{
+       pte_t *ptep;
+       u32 current_level = stage2_pgd_levels - 1;
+
+       *ptep_level = current_level;
+       ptep = (pte_t *)kvm->arch.pgd;
+       ptep = &ptep[stage2_pte_index(addr, current_level)];
+       while (ptep && pte_val(*ptep)) {
+               if (pte_val(*ptep) & _PAGE_LEAF) {
+                       *ptep_level = current_level;
+                       *ptepp = ptep;
+                       return true;
+               }
+
+               if (current_level) {
+                       current_level--;
+                       *ptep_level = current_level;
+                       ptep = (pte_t *)stage2_pte_page_vaddr(*ptep);
+                       ptep = &ptep[stage2_pte_index(addr, current_level)];
+               } else {
+                       ptep = NULL;
+               }
+       }
+
+       return false;
+}
+
+static void stage2_remote_tlb_flush(struct kvm *kvm, u32 level, gpa_t addr)
+{
+       struct cpumask hmask;
+       unsigned long size = PAGE_SIZE;
+       struct kvm_vmid *vmid = &kvm->arch.vmid;
+
+       if (stage2_level_to_page_size(level, &size))
+               return;
+       addr &= ~(size - 1);
+
+       /*
+        * TODO: Instead of cpu_online_mask, we should only target CPUs
+        * where the Guest/VM is running.
+        */
+       preempt_disable();
+       riscv_cpuid_to_hartid_mask(cpu_online_mask, &hmask);
+       sbi_remote_hfence_gvma_vmid(cpumask_bits(&hmask), addr, size,
+                                   READ_ONCE(vmid->vmid));
+       preempt_enable();
+}
+
+static int stage2_set_pte(struct kvm *kvm, u32 level,
+                          struct kvm_mmu_page_cache *pcache,
+                          gpa_t addr, const pte_t *new_pte)
+{
+       u32 current_level = stage2_pgd_levels - 1;
+       pte_t *next_ptep = (pte_t *)kvm->arch.pgd;
+       pte_t *ptep = &next_ptep[stage2_pte_index(addr, current_level)];
+
+       if (current_level < level)
+               return -EINVAL;
+
+       while (current_level != level) {
+               if (pte_val(*ptep) & _PAGE_LEAF)
+                       return -EEXIST;
+
+               if (!pte_val(*ptep)) {
+                       next_ptep = stage2_cache_alloc(pcache);
+                       if (!next_ptep)
+                               return -ENOMEM;
+                       *ptep = pfn_pte(PFN_DOWN(__pa(next_ptep)),
+                                       __pgprot(_PAGE_TABLE));
+               } else {
+                       if (pte_val(*ptep) & _PAGE_LEAF)
+                               return -EEXIST;
+                       next_ptep = (pte_t *)stage2_pte_page_vaddr(*ptep);
+               }
+
+               current_level--;
+               ptep = &next_ptep[stage2_pte_index(addr, current_level)];
+       }
+
+       *ptep = *new_pte;
+       if (pte_val(*ptep) & _PAGE_LEAF)
+               stage2_remote_tlb_flush(kvm, current_level, addr);
+
+       return 0;
+}
+
+static int stage2_map_page(struct kvm *kvm,
+                          struct kvm_mmu_page_cache *pcache,
+                          gpa_t gpa, phys_addr_t hpa,
+                          unsigned long page_size,
+                          bool page_rdonly, bool page_exec)
+{
+       int ret;
+       u32 level = 0;
+       pte_t new_pte;
+       pgprot_t prot;
+
+       ret = stage2_page_size_to_level(page_size, &level);
+       if (ret)
+               return ret;
+
+       /*
+        * A RISC-V implementation can choose to either:
+        * 1) Update 'A' and 'D' PTE bits in hardware
+        * 2) Generate page fault when 'A' and/or 'D' bits are not set
+        *    PTE so that software can update these bits.
+        *
+        * We support both options mentioned above. To achieve this, we
+        * always set 'A' and 'D' PTE bits at time of creating stage2
+        * mapping. To support KVM dirty page logging with both options
+        * mentioned above, we will write-protect stage2 PTEs to track
+        * dirty pages.
+        */
+
+       if (page_exec) {
+               if (page_rdonly)
+                       prot = PAGE_READ_EXEC;
+               else
+                       prot = PAGE_WRITE_EXEC;
+       } else {
+               if (page_rdonly)
+                       prot = PAGE_READ;
+               else
+                       prot = PAGE_WRITE;
+       }
+       new_pte = pfn_pte(PFN_DOWN(hpa), prot);
+       new_pte = pte_mkdirty(new_pte);
+
+       return stage2_set_pte(kvm, level, pcache, gpa, &new_pte);
+}
+
+enum stage2_op {
+       STAGE2_OP_NOP = 0,      /* Nothing */
+       STAGE2_OP_CLEAR,        /* Clear/Unmap */
+       STAGE2_OP_WP,           /* Write-protect */
+};
+
+static void stage2_op_pte(struct kvm *kvm, gpa_t addr,
+                         pte_t *ptep, u32 ptep_level, enum stage2_op op)
+{
+       int i, ret;
+       pte_t *next_ptep;
+       u32 next_ptep_level;
+       unsigned long next_page_size, page_size;
+
+       ret = stage2_level_to_page_size(ptep_level, &page_size);
+       if (ret)
+               return;
+
+       BUG_ON(addr & (page_size - 1));
+
+       if (!pte_val(*ptep))
+               return;
+
+       if (ptep_level && !(pte_val(*ptep) & _PAGE_LEAF)) {
+               next_ptep = (pte_t *)stage2_pte_page_vaddr(*ptep);
+               next_ptep_level = ptep_level - 1;
+               ret = stage2_level_to_page_size(next_ptep_level,
+                                               &next_page_size);
+               if (ret)
+                       return;
+
+               if (op == STAGE2_OP_CLEAR)
+                       set_pte(ptep, __pte(0));
+               for (i = 0; i < PTRS_PER_PTE; i++)
+                       stage2_op_pte(kvm, addr + i * next_page_size,
+                                       &next_ptep[i], next_ptep_level, op);
+               if (op == STAGE2_OP_CLEAR)
+                       put_page(virt_to_page(next_ptep));
+       } else {
+               if (op == STAGE2_OP_CLEAR)
+                       set_pte(ptep, __pte(0));
+               else if (op == STAGE2_OP_WP)
+                       set_pte(ptep, __pte(pte_val(*ptep) & ~_PAGE_WRITE));
+               stage2_remote_tlb_flush(kvm, ptep_level, addr);
+       }
+}
+
+static void stage2_unmap_range(struct kvm *kvm, gpa_t start, gpa_t size)
+{
+       int ret;
+       pte_t *ptep;
+       u32 ptep_level;
+       bool found_leaf;
+       unsigned long page_size;
+       gpa_t addr = start, end = start + size;
+
+       while (addr < end) {
+               found_leaf = stage2_get_leaf_entry(kvm, addr,
+                                                  &ptep, &ptep_level);
+               ret = stage2_level_to_page_size(ptep_level, &page_size);
+               if (ret)
+                       break;
+
+               if (!found_leaf)
+                       goto next;
+
+               if (!(addr & (page_size - 1)) && ((end - addr) >= page_size))
+                       stage2_op_pte(kvm, addr, ptep,
+                                     ptep_level, STAGE2_OP_CLEAR);
+
+next:
+               addr += page_size;
+       }
+}
+
+static void stage2_wp_range(struct kvm *kvm, gpa_t start, gpa_t end)
+{
+       int ret;
+       pte_t *ptep;
+       u32 ptep_level;
+       bool found_leaf;
+       gpa_t addr = start;
+       unsigned long page_size;
+
+       while (addr < end) {
+               found_leaf = stage2_get_leaf_entry(kvm, addr,
+                                                  &ptep, &ptep_level);
+               ret = stage2_level_to_page_size(ptep_level, &page_size);
+               if (ret)
+                       break;
+
+               if (!found_leaf)
+                       goto next;
+
+               if (!(addr & (page_size - 1)) && ((end - addr) >= page_size))
+                       stage2_op_pte(kvm, addr, ptep,
+                                     ptep_level, STAGE2_OP_WP);
+
+next:
+               addr += page_size;
+       }
+}
+
+static void stage2_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;
+
+       spin_lock(&kvm->mmu_lock);
+       stage2_wp_range(kvm, start, end);
+       spin_unlock(&kvm->mmu_lock);
+       kvm_flush_remote_tlbs(kvm);
+}
+
+static int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa,
+                         unsigned long size, bool writable)
+{
+       pte_t pte;
+       int ret = 0;
+       unsigned long pfn;
+       phys_addr_t addr, end;
+       struct kvm_mmu_page_cache pcache = { 0, };
+
+       end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
+       pfn = __phys_to_pfn(hpa);
+
+       for (addr = gpa; addr < end; addr += PAGE_SIZE) {
+               pte = pfn_pte(pfn, PAGE_KERNEL);
+
+               if (!writable)
+                       pte = pte_wrprotect(pte);
+
+               ret = stage2_cache_topup(&pcache,
+                                        stage2_pgd_levels,
+                                        KVM_MMU_PAGE_CACHE_NR_OBJS);
+               if (ret)
+                       goto out;
+
+               spin_lock(&kvm->mmu_lock);
+               ret = stage2_set_pte(kvm, 0, &pcache, addr, &pte);
+               spin_unlock(&kvm->mmu_lock);
+               if (ret)
+                       goto out;
+
+               pfn++;
+       }
+
+out:
+       stage2_cache_flush(&pcache);
+       return ret;
+
+}
+
+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;
+
+       stage2_wp_range(kvm, start, end);
+}
 
 void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
 {
 }
 
+void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
+                                       struct kvm_memory_slot *memslot)
+{
+       kvm_flush_remote_tlbs(kvm);
+}
+
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
 {
 }
@@ -32,7 +436,7 @@ void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
 
 void kvm_arch_flush_shadow_all(struct kvm *kvm)
 {
-       /* TODO: */
+       kvm_riscv_stage2_free_pgd(kvm);
 }
 
 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
@@ -46,7 +450,13 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
                                const struct kvm_memory_slot *new,
                                enum kvm_mr_change change)
 {
-       /* TODO: */
+       /*
+        * 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 && mem->flags & KVM_MEM_LOG_DIRTY_PAGES)
+               stage2_wp_memory_region(kvm, mem->slot);
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
@@ -54,35 +464,255 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                const struct kvm_userspace_memory_region *mem,
                                enum kvm_mr_change change)
 {
-       /* TODO: */
-       return 0;
+       hva_t hva = mem->userspace_addr;
+       hva_t reg_end = hva + mem->memory_size;
+       bool writable = !(mem->flags & KVM_MEM_READONLY);
+       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 ((memslot->base_gfn + memslot->npages) >=
+           (stage2_gpa_size >> PAGE_SHIFT))
+               return -EFAULT;
+
+       mmap_read_lock(current->mm);
+
+       /*
+        * A memory region could potentially cover multiple VMAs, and
+        * any holes between them, so iterate over all of them to find
+        * out if we can map any of them right now.
+        *
+        *     +--------------------------------------------+
+        * +---------------+----------------+   +----------------+
+        * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
+        * +---------------+----------------+   +----------------+
+        *     |               memory region                |
+        *     +--------------------------------------------+
+        */
+       do {
+               struct vm_area_struct *vma = find_vma(current->mm, hva);
+               hva_t vm_start, vm_end;
+
+               if (!vma || vma->vm_start >= reg_end)
+                       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_start = max(hva, vma->vm_start);
+               vm_end = min(reg_end, vma->vm_end);
+
+               if (vma->vm_flags & VM_PFNMAP) {
+                       gpa_t gpa = mem->guest_phys_addr +
+                                   (vm_start - mem->userspace_addr);
+                       phys_addr_t pa;
+
+                       pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
+                       pa += vm_start - vma->vm_start;
+
+                       /* IO region dirty page logging not allowed */
+                       if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+                               ret = -EINVAL;
+                               goto out;
+                       }
+
+                       ret = stage2_ioremap(kvm, gpa, pa,
+                                            vm_end - vm_start, writable);
+                       if (ret)
+                               break;
+               }
+               hva = vm_end;
+       } while (hva < reg_end);
+
+       if (change == KVM_MR_FLAGS_ONLY)
+               goto out;
+
+       spin_lock(&kvm->mmu_lock);
+       if (ret)
+               stage2_unmap_range(kvm, mem->guest_phys_addr,
+                                  mem->memory_size);
+       spin_unlock(&kvm->mmu_lock);
+
+out:
+       mmap_read_unlock(current->mm);
+       return ret;
 }
 
 int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu,
                         struct kvm_memory_slot *memslot,
                         gpa_t gpa, unsigned long hva, bool is_write)
 {
-       /* TODO: */
-       return 0;
+       int ret;
+       kvm_pfn_t hfn;
+       bool writeable;
+       short vma_pageshift;
+       gfn_t gfn = gpa >> PAGE_SHIFT;
+       struct vm_area_struct *vma;
+       struct kvm *kvm = vcpu->kvm;
+       struct kvm_mmu_page_cache *pcache = &vcpu->arch.mmu_page_cache;
+       bool logging = (memslot->dirty_bitmap &&
+                       !(memslot->flags & KVM_MEM_READONLY)) ? true : false;
+       unsigned long vma_pagesize;
+
+       mmap_read_lock(current->mm);
+
+       vma = find_vma_intersection(current->mm, hva, hva + 1);
+       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 == PGDIR_SIZE)
+               gfn = (gpa & huge_page_mask(hstate_vma(vma))) >> PAGE_SHIFT;
+
+       mmap_read_unlock(current->mm);
+
+       if (vma_pagesize != PGDIR_SIZE &&
+           vma_pagesize != PMD_SIZE &&
+           vma_pagesize != PAGE_SIZE) {
+               kvm_err("Invalid VMA page size 0x%lx\n", vma_pagesize);
+               return -EFAULT;
+       }
+
+       /* We need minimum second+third level pages */
+       ret = stage2_cache_topup(pcache, stage2_pgd_levels,
+                                KVM_MMU_PAGE_CACHE_NR_OBJS);
+       if (ret) {
+               kvm_err("Failed to topup stage2 cache\n");
+               return ret;
+       }
+
+       hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable);
+       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)
+               writeable = false;
+
+       spin_lock(&kvm->mmu_lock);
+
+       if (writeable) {
+               kvm_set_pfn_dirty(hfn);
+               mark_page_dirty(kvm, gfn);
+               ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
+                                     vma_pagesize, false, true);
+       } else {
+               ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
+                                     vma_pagesize, true, true);
+       }
+
+       if (ret)
+               kvm_err("Failed to map in stage2\n");
+
+       spin_unlock(&kvm->mmu_lock);
+       kvm_set_pfn_accessed(hfn);
+       kvm_release_pfn_clean(hfn);
+       return ret;
 }
 
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu)
 {
-       /* TODO: */
+       stage2_cache_flush(&vcpu->arch.mmu_page_cache);
 }
 
 int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm)
 {
-       /* TODO: */
+       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(stage2_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_stage2_free_pgd(struct kvm *kvm)
 {
-       /* TODO: */
+       void *pgd = NULL;
+
+       spin_lock(&kvm->mmu_lock);
+       if (kvm->arch.pgd) {
+               stage2_unmap_range(kvm, 0UL, stage2_gpa_size);
+               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(stage2_pgd_size));
 }
 
 void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu)
 {
-       /* TODO: */
+       unsigned long hgatp = stage2_mode;
+       struct kvm_arch *k = &vcpu->kvm->arch;
+
+       hgatp |= (READ_ONCE(k->vmid.vmid) << HGATP_VMID_SHIFT) &
+                HGATP_VMID_MASK;
+       hgatp |= (k->pgd_phys >> PAGE_SHIFT) & HGATP_PPN;
+
+       csr_write(CSR_HGATP, hgatp);
+
+       if (!kvm_riscv_stage2_vmid_bits())
+               __kvm_riscv_hfence_gvma_all();
+}
+
+void kvm_riscv_stage2_mode_detect(void)
+{
+#ifdef CONFIG_64BIT
+       /* Try Sv48x4 stage2 mode */
+       csr_write(CSR_HGATP, HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
+       if ((csr_read(CSR_HGATP) >> HGATP_MODE_SHIFT) == HGATP_MODE_SV48X4) {
+               stage2_mode = (HGATP_MODE_SV48X4 << HGATP_MODE_SHIFT);
+               stage2_pgd_levels = 4;
+       }
+       csr_write(CSR_HGATP, 0);
+
+       __kvm_riscv_hfence_gvma_all();
+#endif
+}
+
+unsigned long kvm_riscv_stage2_mode(void)
+{
+       return stage2_mode >> HGATP_MODE_SHIFT;
 }
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index 282d67617229..6cde69a82252 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -12,12 +12,6 @@
 #include <linux/uaccess.h>
 #include <linux/kvm_host.h>
 
-int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
-{
-       /* TODO: To be added later. */
-       return -EOPNOTSUPP;
-}
-
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
        int r;
-- 
2.25.1

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