Re: [PATCH v13 27/48] arm64: RMI: Runtime faulting of memory

Wei-Lin Chang
2026-03-19T18:41:15Z

On Wed, Mar 18, 2026 at 03:53:51PM +0000, Steven Price wrote:
> At runtime if the realm guest accesses memory which hasn't yet been
> mapped then KVM needs to either populate the region or fault the guest.
>
> For memory in the lower (protected) region of IPA a fresh page is
> provided to the RMM which will zero the contents. For memory in the
> upper (shared) region of IPA, the memory from the memslot is mapped
> into the realm VM non secure.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v12:
> * Switch to RMM v2.0 range based APIs.
> Changes since v11:
> * Adapt to upstream changes.
> Changes since v10:
> * RME->RMI renaming.
> * Adapt to upstream gmem changes.
> Changes since v9:
> * Fix call to kvm_stage2_unmap_range() in kvm_free_stage2_pgd() to set
> may_block to avoid stall warnings.
> * Minor coding style fixes.
> Changes since v8:
> * Propagate the may_block flag.
> * Minor comments and coding style changes.
> Changes since v7:
> * Remove redundant WARN_ONs for realm_create_rtt_levels() - it will
> internally WARN when necessary.
> Changes since v6:
> * Handle PAGE_SIZE being larger than RMM granule size.
> * Some minor renaming following review comments.
> Changes since v5:
> * Reduce use of struct page in preparation for supporting the RMM
> having a different page size to the host.
> * Handle a race when delegating a page where another CPU has faulted on
> a the same page (and already delegated the physical page) but not yet
> mapped it. In this case simply return to the guest to either use the
> mapping from the other CPU (or refault if the race is lost).
> * The changes to populate_par_region() are moved into the previous
> patch where they belong.
> Changes since v4:
> * Code cleanup following review feedback.
> * Drop the PTE_SHARED bit when creating unprotected page table entries.
> This is now set by the RMM and the host has no control of it and the
> spec requires the bit to be set to zero.
> Changes since v2:
> * Avoid leaking memory if failing to map it in the realm.
> * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
> * Adapt to changes in previous patches.
> ---
> arch/arm64/include/asm/kvm_emulate.h | 8 ++
> arch/arm64/include/asm/kvm_rmi.h | 12 ++
> arch/arm64/kvm/mmu.c | 139 ++++++++++++++++--
> arch/arm64/kvm/rmi.c | 206 +++++++++++++++++++++++++++
> 4 files changed, 351 insertions(+), 14 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index d194d91fbc2a..0734c4a65174 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -706,6 +706,14 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
> return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
> }
>
> +static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t ipa)

I think we should use gpa_t as the type for ipa.

> +{
> + if (!kvm_is_realm(kvm))
> + return ipa;
> +
> + return ipa & ~BIT(kvm->arch.realm.ia_bits - 1);
> +}
> +
> static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
> {
> return kvm_is_realm(vcpu->kvm);
> diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h
> index bf663bb240c4..38208be3c602 100644
> --- a/arch/arm64/include/asm/kvm_rmi.h
> +++ b/arch/arm64/include/asm/kvm_rmi.h
> @@ -6,6 +6,7 @@
> #ifndef __ASM_KVM_RMI_H
> #define __ASM_KVM_RMI_H
>
> +#include <asm/kvm_pgtable.h>
> #include <asm/rmi_smc.h>
>
> /**
> @@ -105,6 +106,17 @@ void kvm_realm_unmap_range(struct kvm *kvm,
> unsigned long size,
> bool unmap_private,
> bool may_block);
> +int realm_map_protected(struct kvm *kvm,
> + unsigned long base_ipa,
> + kvm_pfn_t pfn,
> + unsigned long size,
> + struct kvm_mmu_memory_cache *memcache);
> +int realm_map_non_secure(struct realm *realm,
> + unsigned long ipa,
> + kvm_pfn_t pfn,
> + unsigned long size,
> + enum kvm_pgtable_prot prot,
> + struct kvm_mmu_memory_cache *memcache);
>
> static inline bool kvm_realm_is_private_address(struct realm *realm,
> unsigned long addr)
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index bad93938acdb..73c18c2861a2 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -334,8 +334,15 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
>
> lockdep_assert_held_write(&kvm->mmu_lock);
> WARN_ON(size & ~PAGE_MASK);
> - WARN_ON(stage2_apply_range(mmu, start, end, KVM_PGT_FN(kvm_pgtable_stage2_unmap),
> - may_block));
> +
> + if (kvm_is_realm(kvm)) {
> + kvm_realm_unmap_range(kvm, start, size, !only_shared,
> + may_block);
> + } else {
> + WARN_ON(stage2_apply_range(mmu, start, end,
> + KVM_PGT_FN(kvm_pgtable_stage2_unmap),
> + may_block));
> + }
> }
>
> void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
> @@ -355,7 +362,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
> phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
> phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
>
> - kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
> + if (kvm_is_realm(kvm))
> + kvm_realm_unmap_range(kvm, addr, end - addr, false, true);
> + else
> + kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
> }
>
> /**
> @@ -1081,6 +1091,10 @@ void stage2_unmap_vm(struct kvm *kvm)
> struct kvm_memory_slot *memslot;
> int idx, bkt;
>
> + /* For realms this is handled by the RMM so nothing to do here */
> + if (kvm_is_realm(kvm))
> + return;
> +
> idx = srcu_read_lock(&kvm->srcu);
> mmap_read_lock(current->mm);
> write_lock(&kvm->mmu_lock);
> @@ -1106,6 +1120,9 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
> if (kvm_is_realm(kvm) &&
> (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
> kvm_realm_state(kvm) != REALM_STATE_NONE)) {
> + struct realm *realm = &kvm->arch.realm;
> +
> + kvm_stage2_unmap_range(mmu, 0, BIT(realm->ia_bits - 1), true);
> write_unlock(&kvm->mmu_lock);
> kvm_realm_destroy_rtts(kvm);
>
> @@ -1516,6 +1533,29 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
> return vma->vm_flags & VM_MTE_ALLOWED;
> }
>
> +static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
> + kvm_pfn_t pfn, unsigned long map_size,
> + enum kvm_pgtable_prot prot,
> + struct kvm_mmu_memory_cache *memcache)
> +{
> + struct realm *realm = &kvm->arch.realm;
> +
> + /*
> + * Write permission is required for now even though it's possible to
> + * map unprotected pages (granules) as read-only. It's impossible to
> + * map protected pages (granules) as read-only.
> + */
> + if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
> + return -EFAULT;
> +
> + ipa = ALIGN_DOWN(ipa, PAGE_SIZE);
> + if (!kvm_realm_is_private_address(realm, ipa))
> + return realm_map_non_secure(realm, ipa, pfn, map_size, prot,
> + memcache);
> +
> + return realm_map_protected(kvm, ipa, pfn, map_size, memcache);
> +}
> +
> static bool kvm_vma_is_cacheable(struct vm_area_struct *vma)
> {
> switch (FIELD_GET(PTE_ATTRINDX_MASK, pgprot_val(vma->vm_page_prot))) {
> @@ -1588,6 +1628,7 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_SHARED;
> enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
> struct kvm_pgtable *pgt = vcpu->arch.hw_mmu->pgt;
> + gpa_t gpa = kvm_gpa_from_fault(vcpu->kvm, fault_ipa);
> unsigned long mmu_seq;
> struct page *page;
> struct kvm *kvm = vcpu->kvm;
> @@ -1596,6 +1637,29 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> gfn_t gfn;
> int ret;
>
> + if (kvm_is_realm(vcpu->kvm)) {
> + /* check for memory attribute mismatch */
> + bool is_priv_gfn = kvm_mem_is_private(kvm, gpa >> PAGE_SHIFT);
> + /*
> + * For Realms, the shared address is an alias of the private
> + * PA with the top bit set. Thus is the fault address matches

Hi,

Thus is -> Thus if.

> + * the GPA then it is the private alias.
> + */
> + bool is_priv_fault = (gpa == fault_ipa);
> +
> + if (is_priv_gfn != is_priv_fault) {
> + kvm_prepare_memory_fault_exit(vcpu, gpa, PAGE_SIZE,
> + kvm_is_write_fault(vcpu),
> + false,
> + is_priv_fault);
> + /*
> + * KVM_EXIT_MEMORY_FAULT requires an return code of
> + * -EFAULT, see the API documentation
> + */
> + return -EFAULT;
> + }
> + }
> +
> ret = prepare_mmu_memcache(vcpu, true, &memcache);
> if (ret)
> return ret;
> @@ -1603,7 +1667,7 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> if (nested)
> gfn = kvm_s2_trans_output(nested) >> PAGE_SHIFT;
> else
> - gfn = fault_ipa >> PAGE_SHIFT;
> + gfn = gpa >> PAGE_SHIFT;
>
> write_fault = kvm_is_write_fault(vcpu);
> exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
> @@ -1616,7 +1680,7 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>
> ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, &page, NULL);
> if (ret) {
> - kvm_prepare_memory_fault_exit(vcpu, fault_ipa, PAGE_SIZE,
> + kvm_prepare_memory_fault_exit(vcpu, gpa, PAGE_SIZE,
> write_fault, exec_fault, false);
> return ret;
> }
> @@ -1638,15 +1702,25 @@ static int gmem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> kvm_fault_lock(kvm);
> if (mmu_invalidate_retry(kvm, mmu_seq)) {
> ret = -EAGAIN;
> - goto out_unlock;
> + goto out_release_page;
> + }
> +
> + if (kvm_is_realm(kvm)) {
> + ret = realm_map_ipa(kvm, fault_ipa, pfn,
> + PAGE_SIZE, KVM_PGTABLE_PROT_W, memcache);
> + /* if successful don't release the page */
> + if (!ret)
> + goto out_unlock;
> + goto out_release_page;
> }
>
> ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault_ipa, PAGE_SIZE,
> __pfn_to_phys(pfn), prot,
> memcache, flags);
>
> -out_unlock:
> +out_release_page:
> kvm_release_faultin_page(kvm, page, !!ret, writable);
> +out_unlock:
> kvm_fault_unlock(kvm);
>
> if (writable && !ret)
> @@ -1685,6 +1759,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> if (fault_is_perm)
> fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
> write_fault = kvm_is_write_fault(vcpu);
> +
> + /*
> + * Realms cannot map protected pages read-only
> + * FIXME: It should be possible to map unprotected pages read-only
> + */
> + if (vcpu_is_rec(vcpu))
> + write_fault = true;
> +
> exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
> VM_WARN_ON_ONCE(write_fault && exec_fault);
>
> @@ -1779,7 +1861,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> ipa &= ~(vma_pagesize - 1);
> }
>
> - gfn = ipa >> PAGE_SHIFT;
> + gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
> mte_allowed = kvm_vma_mte_allowed(vma);
>
> vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
> @@ -1855,6 +1937,15 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> if (exec_fault && s2_force_noncacheable)
> ret = -ENOEXEC;
>
> + /*
> + * For now we shouldn't be hitting protected addresses because they are
> + * handled in gmem_abort(). In the future this check may be relaxed to
> + * support e.g. protected devices.
> + */
> + if (!ret && vcpu_is_rec(vcpu) &&
> + kvm_gpa_from_fault(kvm, fault_ipa) == fault_ipa)

Maybe use !shared_ipa_fault() here?

Thanks,
Wei-Lin Chang

> + ret = -EINVAL;
> +
> if (ret) {
> kvm_release_page_unused(page);
> return ret;
> @@ -1939,6 +2030,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
> */
> prot &= ~KVM_NV_GUEST_MAP_SZ;
> ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, fault_ipa, prot, flags);
> + } else if (kvm_is_realm(kvm)) {
> + ret = realm_map_ipa(kvm, fault_ipa, pfn, vma_pagesize,
> + prot, memcache);
> } else {
> ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault_ipa, vma_pagesize,
> __pfn_to_phys(pfn), prot,
> @@ -2049,6 +2143,13 @@ int kvm_handle_guest_sea(struct kvm_vcpu *vcpu)
> return 0;
> }
>
> +static bool shared_ipa_fault(struct kvm *kvm, phys_addr_t fault_ipa)
> +{
> + gpa_t gpa = kvm_gpa_from_fault(kvm, fault_ipa);
> +
> + return (gpa != fault_ipa);
> +}
> +
> /**
> * kvm_handle_guest_abort - handles all 2nd stage aborts
> * @vcpu: the VCPU pointer
> @@ -2159,8 +2260,9 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
> nested = &nested_trans;
> }
>
> - gfn = ipa >> PAGE_SHIFT;
> + gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
> memslot = gfn_to_memslot(vcpu->kvm, gfn);
> +
> hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
> write_fault = kvm_is_write_fault(vcpu);
> if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
> @@ -2203,7 +2305,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
> * of the page size.
> */
> ipa |= FAR_TO_FIPA_OFFSET(kvm_vcpu_get_hfar(vcpu));
> - ret = io_mem_abort(vcpu, ipa);
> + ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
> goto out_unlock;
> }
>
> @@ -2219,7 +2321,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
> VM_WARN_ON_ONCE(kvm_vcpu_trap_is_permission_fault(vcpu) &&
> !write_fault && !kvm_vcpu_trap_is_exec_fault(vcpu));
>
> - if (kvm_slot_has_gmem(memslot))
> + if (kvm_slot_has_gmem(memslot) && !shared_ipa_fault(vcpu->kvm, fault_ipa))
> ret = gmem_abort(vcpu, fault_ipa, nested, memslot,
> esr_fsc_is_permission_fault(esr));
> else
> @@ -2256,6 +2358,10 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> if (!kvm->arch.mmu.pgt)
> return false;
>
> + /* We don't support aging for Realms */
> + if (kvm_is_realm(kvm))
> + return true;
> +
> return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
> range->start << PAGE_SHIFT,
> size, true);
> @@ -2272,6 +2378,10 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> if (!kvm->arch.mmu.pgt)
> return false;
>
> + /* We don't support aging for Realms */
> + if (kvm_is_realm(kvm))
> + return true;
> +
> return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
> range->start << PAGE_SHIFT,
> size, false);
> @@ -2438,10 +2548,11 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
> return -EFAULT;
>
> /*
> - * Only support guest_memfd backed memslots with mappable memory, since
> - * there aren't any CoCo VMs that support only private memory on arm64.
> + * Only support guest_memfd backed memslots with mappable memory,
> + * unless the guest is a CCA realm guest.
> */
> - if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new))
> + if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new) &&
> + !kvm_is_realm(kvm))
> return -EINVAL;
>
> hva = new->userspace_addr;
> diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c
> index d5fee203824b..30292814b1ec 100644
> --- a/arch/arm64/kvm/rmi.c
> +++ b/arch/arm64/kvm/rmi.c
> @@ -837,6 +837,212 @@ static int realm_create_protected_data_page(struct kvm *kvm,
> return ret;
> }
>
> +static int fold_rtt(struct realm *realm, unsigned long addr, int level)
> +{
> + phys_addr_t rtt_addr;
> + int ret;
> +
> + ret = realm_rtt_fold(realm, addr, level, &rtt_addr);
> + if (ret)
> + return ret;
> +
> + free_rtt(rtt_addr);
> +
> + return 0;
> +}
> +
> +static unsigned long addr_range_desc(unsigned long phys, unsigned long size)
> +{
> + unsigned long out = 0;
> +
> + switch (size) {
> + case P4D_SIZE:
> + out = 0 | (1 << 2);
> + break;
> + case PUD_SIZE:
> + out = 1 | (1 << 2);
> + break;
> + case PMD_SIZE:
> + out = 2 | (1 << 2);
> + break;
> + case PAGE_SIZE:
> + out = 3 | (1 << 2);
> + break;
> + default:
> + /*
> + * Only support mapping at the page level granulatity when
> + * it's an unusual length. This should get us back onto a larger
> + * block size for the subsequent mappings.
> + */
> + out = 3 | ((MIN(size >> PAGE_SHIFT, PTRS_PER_PTE - 1)) << 2);
> + break;
> + }
> +
> + WARN_ON(phys & ~PAGE_MASK);
> +
> + out |= phys & PAGE_MASK;
> +
> + return out;
> +}
> +
> +int realm_map_protected(struct kvm *kvm,
> + unsigned long ipa,
> + kvm_pfn_t pfn,
> + unsigned long map_size,
> + struct kvm_mmu_memory_cache *memcache)
> +{
> + struct realm *realm = &kvm->arch.realm;
> + phys_addr_t phys = __pfn_to_phys(pfn);
> + phys_addr_t rd = virt_to_phys(realm->rd);
> + unsigned long base_ipa = ipa;
> + unsigned long ipa_top = ipa + map_size;
> + int map_level = IS_ALIGNED(map_size, RMM_L2_BLOCK_SIZE) ?
> + RMM_RTT_BLOCK_LEVEL : RMM_RTT_MAX_LEVEL;
> + int ret = 0;
> +
> + if (WARN_ON(!IS_ALIGNED(map_size, PAGE_SIZE) ||
> + !IS_ALIGNED(ipa, map_size)))
> + return -EINVAL;
> +
> + if (map_level < RMM_RTT_MAX_LEVEL) {
> + /*
> + * A temporary RTT is needed during the map, precreate it,
> + * however if there is an error (e.g. missing parent tables)
> + * this will be handled below.
> + */
> + realm_create_rtt_levels(realm, ipa, map_level,
> + RMM_RTT_MAX_LEVEL, memcache);
> + }
> +
> + if (delegate_range(phys, map_size)) {
> + /*
> + * It's likely we raced with another VCPU on the same
> + * fault. Assume the other VCPU has handled the fault
> + * and return to the guest.
> + */
> + return 0;
> + }
> +
> + while (ipa < ipa_top) {
> + unsigned long flags = RMI_ADDR_TYPE_SINGLE;
> + unsigned long range_desc = addr_range_desc(phys, ipa_top - ipa);
> + unsigned long out_top;
> +
> + ret = rmi_rtt_data_map(rd, ipa, ipa_top, flags, range_desc,
> + &out_top);
> +
> + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
> + /* Create missing RTTs and retry */
> + int level = RMI_RETURN_INDEX(ret);
> +
> + WARN_ON(level == RMM_RTT_MAX_LEVEL);
> + ret = realm_create_rtt_levels(realm, ipa, level,
> + RMM_RTT_MAX_LEVEL,
> + memcache);
> + if (ret)
> + goto err_undelegate;
> +
> + ret = rmi_rtt_data_map(rd, ipa, ipa_top, flags,
> + range_desc, &out_top);
> + }
> +
> + if (WARN_ON(ret))
> + goto err_undelegate;
> +
> + phys += out_top - ipa;
> + ipa = out_top;
> + }
> +
> + if (map_size == RMM_L2_BLOCK_SIZE) {
> + ret = fold_rtt(realm, base_ipa, map_level + 1);
> + if (WARN_ON(ret))
> + goto err;
> + }
> +
> + return 0;
> +
> +err_undelegate:
> + if (WARN_ON(undelegate_range(phys, map_size))) {
> + /* Page can't be returned to NS world so is lost */
> + get_page(phys_to_page(phys));
> + }
> +err:
> + realm_unmap_private_range(kvm, base_ipa, ipa, true);
> + return -ENXIO;
> +}
> +
> +int realm_map_non_secure(struct realm *realm,
> + unsigned long ipa,
> + kvm_pfn_t pfn,
> + unsigned long size,
> + enum kvm_pgtable_prot prot,
> + struct kvm_mmu_memory_cache *memcache)
> +{
> + unsigned long attr;
> + phys_addr_t rd = virt_to_phys(realm->rd);
> + phys_addr_t phys = __pfn_to_phys(pfn);
> + unsigned long offset;
> + /* TODO: Support block mappings */
> + int map_level = RMM_RTT_MAX_LEVEL;
> + int map_size = rmi_rtt_level_mapsize(map_level);
> + int ret = 0;
> +
> + if (WARN_ON(!IS_ALIGNED(size, PAGE_SIZE) ||
> + !IS_ALIGNED(ipa, size)))
> + return -EINVAL;
> +
> + switch (prot & (KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_NORMAL_NC)) {
> + case KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_NORMAL_NC:
> + return -EINVAL;
> + case KVM_PGTABLE_PROT_DEVICE:
> + attr = PTE_S2_MEMATTR(MT_S2_FWB_DEVICE_nGnRE);
> + break;
> + case KVM_PGTABLE_PROT_NORMAL_NC:
> + attr = PTE_S2_MEMATTR(MT_S2_FWB_NORMAL_NC);
> + break;
> + default:
> + attr = PTE_S2_MEMATTR(MT_S2_FWB_NORMAL);
> + }
> +
> + for (offset = 0; offset < size; offset += map_size) {
> + /*
> + * realm_map_ipa() enforces that the memory is writable,
> + * so for now we permit both read and write.
> + */
> + unsigned long desc = kvm_phys_to_pte(phys) | attr |
> + KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R |
> + KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
> + ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
> +
> + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
> + /* Create missing RTTs and retry */
> + int level = RMI_RETURN_INDEX(ret);
> +
> + ret = realm_create_rtt_levels(realm, ipa, level,
> + map_level, memcache);
> + if (ret)
> + return -ENXIO;
> +
> + ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
> + }
> + /*
> + * RMI_ERROR_RTT can be reported for two reasons: either the
> + * RTT tables are not there, or there is an RTTE already
> + * present for the address. The above call to create RTTs
> + * handles the first case, and in the second case this
> + * indicates that another thread has already populated the RTTE
> + * for us, so we can ignore the error and continue.
> + */
> + if (ret && RMI_RETURN_STATUS(ret) != RMI_ERROR_RTT)
> + return -ENXIO;
> +
> + ipa += map_size;
> + phys += map_size;
> + }
> +
> + return 0;
> +}
> +
> static int populate_region_cb(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
> struct page *src_page, void *opaque)
> {
> --
> 2.43.0
>