Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Will writes:
  "Late arm64 fixes

   - Fix handling of young contiguous ptes for hugetlb mappings

   - Fix livelock when taking access faults on contiguous hugetlb mappings

   - Tighten up register accesses via KVM SET_ONE_REG ioctl()s"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: KVM: Sanitize PSTATE.M when being set from userspace
  arm64: KVM: Tighten guest core register access from userspace
  arm64: hugetlb: Avoid unnecessary clearing in huge_ptep_set_access_flags
  arm64: hugetlb: Fix handling of young ptes

arch/arm64/kvm/guest.c

@@ -57,6 +57,45 @@ static u64 core_reg_offset_from_id(u64 id)
 	return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
 }
 
+static int validate_core_offset(const struct kvm_one_reg *reg)
+{
+	u64 off = core_reg_offset_from_id(reg->id);
+	int size;
+
+	switch (off) {
+	case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
+	     KVM_REG_ARM_CORE_REG(regs.regs[30]):
+	case KVM_REG_ARM_CORE_REG(regs.sp):
+	case KVM_REG_ARM_CORE_REG(regs.pc):
+	case KVM_REG_ARM_CORE_REG(regs.pstate):
+	case KVM_REG_ARM_CORE_REG(sp_el1):
+	case KVM_REG_ARM_CORE_REG(elr_el1):
+	case KVM_REG_ARM_CORE_REG(spsr[0]) ...
+	     KVM_REG_ARM_CORE_REG(spsr[KVM_NR_SPSR - 1]):
+		size = sizeof(__u64);
+		break;
+
+	case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ...
+	     KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]):
+		size = sizeof(__uint128_t);
+		break;
+
+	case KVM_REG_ARM_CORE_REG(fp_regs.fpsr):
+	case KVM_REG_ARM_CORE_REG(fp_regs.fpcr):
+		size = sizeof(__u32);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (KVM_REG_SIZE(reg->id) == size &&
+	    IS_ALIGNED(off, size / sizeof(__u32)))
+		return 0;
+
+	return -EINVAL;
+}
+
 static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
 	/*
@@ -76,6 +115,9 @@ static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	    (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
 		return -ENOENT;
 
+	if (validate_core_offset(reg))
+		return -EINVAL;
+
 	if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id)))
 		return -EFAULT;
 
@@ -98,6 +140,9 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	    (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
 		return -ENOENT;
 
+	if (validate_core_offset(reg))
+		return -EINVAL;
+
 	if (KVM_REG_SIZE(reg->id) > sizeof(tmp))
 		return -EINVAL;
 
@@ -107,17 +152,25 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	}
 
 	if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) {
-		u32 mode = (*(u32 *)valp) & PSR_AA32_MODE_MASK;
+		u64 mode = (*(u64 *)valp) & PSR_AA32_MODE_MASK;
 		switch (mode) {
 		case PSR_AA32_MODE_USR:
+			if (!system_supports_32bit_el0())
+				return -EINVAL;
+			break;
 		case PSR_AA32_MODE_FIQ:
 		case PSR_AA32_MODE_IRQ:
 		case PSR_AA32_MODE_SVC:
 		case PSR_AA32_MODE_ABT:
 		case PSR_AA32_MODE_UND:
+			if (!vcpu_el1_is_32bit(vcpu))
+				return -EINVAL;
+			break;
 		case PSR_MODE_EL0t:
 		case PSR_MODE_EL1t:
 		case PSR_MODE_EL1h:
+			if (vcpu_el1_is_32bit(vcpu))
+				return -EINVAL;
 			break;
 		default:
 			err = -EINVAL;

arch/arm64/mm/hugetlbpage.c

@@ -117,11 +117,14 @@ static pte_t get_clear_flush(struct mm_struct *mm,
 
 		/*
 		 * If HW_AFDBM is enabled, then the HW could turn on
-		 * the dirty bit for any page in the set, so check
-		 * them all.  All hugetlb entries are already young.
+		 * the dirty or accessed bit for any page in the set,
+		 * so check them all.
 		 */
 		if (pte_dirty(pte))
 			orig_pte = pte_mkdirty(orig_pte);
+
+		if (pte_young(pte))
+			orig_pte = pte_mkyoung(orig_pte);
 	}
 
 	if (valid) {
@@ -320,11 +323,40 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 	return get_clear_flush(mm, addr, ptep, pgsize, ncontig);
 }
 
+/*
+ * huge_ptep_set_access_flags will update access flags (dirty, accesssed)
+ * and write permission.
+ *
+ * For a contiguous huge pte range we need to check whether or not write
+ * permission has to change only on the first pte in the set. Then for
+ * all the contiguous ptes we need to check whether or not there is a
+ * discrepancy between dirty or young.
+ */
+static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig)
+{
+	int i;
+
+	if (pte_write(pte) != pte_write(huge_ptep_get(ptep)))
+		return 1;
+
+	for (i = 0; i < ncontig; i++) {
+		pte_t orig_pte = huge_ptep_get(ptep + i);
+
+		if (pte_dirty(pte) != pte_dirty(orig_pte))
+			return 1;
+
+		if (pte_young(pte) != pte_young(orig_pte))
+			return 1;
+	}
+
+	return 0;
+}
+
 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr, pte_t *ptep,
 			       pte_t pte, int dirty)
 {
-	int ncontig, i, changed = 0;
+	int ncontig, i;
 	size_t pgsize = 0;
 	unsigned long pfn = pte_pfn(pte), dpfn;
 	pgprot_t hugeprot;
@@ -336,19 +368,23 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 	ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
 	dpfn = pgsize >> PAGE_SHIFT;
 
+	if (!__cont_access_flags_changed(ptep, pte, ncontig))
+		return 0;
+
 	orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
-	if (!pte_same(orig_pte, pte))
-		changed = 1;
 
-	/* Make sure we don't lose the dirty state */
+	/* Make sure we don't lose the dirty or young state */
 	if (pte_dirty(orig_pte))
 		pte = pte_mkdirty(pte);
 
+	if (pte_young(orig_pte))
+		pte = pte_mkyoung(pte);
+
 	hugeprot = pte_pgprot(pte);
 	for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
 		set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot));
 
-	return changed;
+	return 1;
 }
 
 void huge_ptep_set_wrprotect(struct mm_struct *mm,