From: Anup Patel anup.patel@wdc.com
euleros inclusion category: feature bugzilla: NA CVE: NA
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.
Link: https://gitee.com/openeuler/kernel/issues/I1RR1Y Signed-off-by: Anup Patel anup.patel@wdc.com Acked-by: Paolo Bonzini pbonzini@redhat.com Reviewed-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Mingwang Li limingwang@huawei.com Reviewed-by: Yifei Jiang jiangyifei@huawei.com Signed-off-by: Xie XiuQi xiexiuqi@huawei.com --- arch/riscv/include/asm/kvm_host.h | 10 + arch/riscv/include/asm/pgtable-bits.h | 1 + arch/riscv/kvm/mmu.c | 574 +++++++++++++++++++++++++- 3 files changed, 575 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 981f3cade325..9e754c0848b3 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; @@ -174,6 +181,9 @@ 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;
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/mmu.c b/arch/riscv/kvm/mmu.c index 8fb356e68cc5..3d13e15e7555 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -17,6 +17,357 @@ #include <linux/sched/signal.h> #include <asm/page.h> #include <asm/pgtable.h> +#include <asm/sbi.h> + +#ifdef CONFIG_64BIT +#define stage2_have_pmd true +#define stage2_gpa_size ((gpa_t)(1ULL << 39)) +#define stage2_pgd_levels 3 +#define stage2_index_bits 9 +#else +#define stage2_have_pmd false +#define stage2_gpa_size ((gpa_t)(1ULL << 32)) +#define stage2_pgd_levels 2 +#define stage2_index_bits 10 +#endif + +#define stage2_pte_index(addr, level) \ +(((addr) >> (PAGE_SHIFT + stage2_index_bits * (level))) & (PTRS_PER_PTE - 1)) + +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) +{ + if (page_size == PAGE_SIZE) + *out_level = 0; + else if (page_size == PMD_SIZE) + *out_level = 1; + else if (page_size == PGDIR_SIZE) + *out_level = (stage2_have_pmd) ? 2 : 1; + else + return -EINVAL; + + return 0; +} + +static int stage2_level_to_page_size(u32 level, unsigned long *out_pgsize) +{ + switch (level) { + case 0: + *out_pgsize = PAGE_SIZE; + break; + case 1: + *out_pgsize = (stage2_have_pmd) ? PMD_SIZE : PGDIR_SIZE; + break; + case 2: + *out_pgsize = PGDIR_SIZE; + break; + default: + return -EINVAL; + } + + 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, pgprot_t prot) +{ + int ret; + u32 level = 0; + pte_t new_pte; + + ret = stage2_page_size_to_level(page_size, &level); + if (ret) + return ret; + + new_pte = pfn_pte(PFN_DOWN(hpa), prot); + 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; + } +} + +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); +} + +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_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot) { @@ -38,7 +389,7 @@ 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, @@ -52,7 +403,13 @@ 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 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, @@ -60,35 +417,232 @@ 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, PAGE_WRITE_EXEC); + } else { + ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT, + vma_pagesize, PAGE_READ_EXEC); + } + + 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: */ + if (kvm->arch.pgd != NULL) { + kvm_err("kvm_arch already initialized?\n"); + return -EINVAL; + } + + kvm->arch.pgd = alloc_pages_exact(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO); + if (!kvm->arch.pgd) + return -ENOMEM; + kvm->arch.pgd_phys = virt_to_phys(kvm->arch.pgd); + 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); + + /* Free the HW pgd, one page at a time */ + if (pgd) + free_pages_exact(pgd, PAGE_SIZE); }
void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu) { - /* TODO: */ + unsigned long hgatp = HGATP_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(); }