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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /arch/powerpc/kvm/book3s_hv_uvmem.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_uvmem.c')
-rw-r--r--arch/powerpc/kvm/book3s_hv_uvmem.c1215
1 files changed, 1215 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
new file mode 100644
index 000000000..3dd58b4ee
--- /dev/null
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -0,0 +1,1215 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Secure pages management: Migration of pages between normal and secure
+ * memory of KVM guests.
+ *
+ * Copyright 2018 Bharata B Rao, IBM Corp. <bharata@linux.ibm.com>
+ */
+
+/*
+ * A pseries guest can be run as secure guest on Ultravisor-enabled
+ * POWER platforms. On such platforms, this driver will be used to manage
+ * the movement of guest pages between the normal memory managed by
+ * hypervisor (HV) and secure memory managed by Ultravisor (UV).
+ *
+ * The page-in or page-out requests from UV will come to HV as hcalls and
+ * HV will call back into UV via ultracalls to satisfy these page requests.
+ *
+ * Private ZONE_DEVICE memory equal to the amount of secure memory
+ * available in the platform for running secure guests is hotplugged.
+ * Whenever a page belonging to the guest becomes secure, a page from this
+ * private device memory is used to represent and track that secure page
+ * on the HV side. Some pages (like virtio buffers, VPA pages etc) are
+ * shared between UV and HV. However such pages aren't represented by
+ * device private memory and mappings to shared memory exist in both
+ * UV and HV page tables.
+ */
+
+/*
+ * Notes on locking
+ *
+ * kvm->arch.uvmem_lock is a per-guest lock that prevents concurrent
+ * page-in and page-out requests for the same GPA. Concurrent accesses
+ * can either come via UV (guest vCPUs requesting for same page)
+ * or when HV and guest simultaneously access the same page.
+ * This mutex serializes the migration of page from HV(normal) to
+ * UV(secure) and vice versa. So the serialization points are around
+ * migrate_vma routines and page-in/out routines.
+ *
+ * Per-guest mutex comes with a cost though. Mainly it serializes the
+ * fault path as page-out can occur when HV faults on accessing secure
+ * guest pages. Currently UV issues page-in requests for all the guest
+ * PFNs one at a time during early boot (UV_ESM uvcall), so this is
+ * not a cause for concern. Also currently the number of page-outs caused
+ * by HV touching secure pages is very very low. If an when UV supports
+ * overcommitting, then we might see concurrent guest driven page-outs.
+ *
+ * Locking order
+ *
+ * 1. kvm->srcu - Protects KVM memslots
+ * 2. kvm->mm->mmap_lock - find_vma, migrate_vma_pages and helpers, ksm_madvise
+ * 3. kvm->arch.uvmem_lock - protects read/writes to uvmem slots thus acting
+ * as sync-points for page-in/out
+ */
+
+/*
+ * Notes on page size
+ *
+ * Currently UV uses 2MB mappings internally, but will issue H_SVM_PAGE_IN
+ * and H_SVM_PAGE_OUT hcalls in PAGE_SIZE(64K) granularity. HV tracks
+ * secure GPAs at 64K page size and maintains one device PFN for each
+ * 64K secure GPA. UV_PAGE_IN and UV_PAGE_OUT calls by HV are also issued
+ * for 64K page at a time.
+ *
+ * HV faulting on secure pages: When HV touches any secure page, it
+ * faults and issues a UV_PAGE_OUT request with 64K page size. Currently
+ * UV splits and remaps the 2MB page if necessary and copies out the
+ * required 64K page contents.
+ *
+ * Shared pages: Whenever guest shares a secure page, UV will split and
+ * remap the 2MB page if required and issue H_SVM_PAGE_IN with 64K page size.
+ *
+ * HV invalidating a page: When a regular page belonging to secure
+ * guest gets unmapped, HV informs UV with UV_PAGE_INVAL of 64K
+ * page size. Using 64K page size is correct here because any non-secure
+ * page will essentially be of 64K page size. Splitting by UV during sharing
+ * and page-out ensures this.
+ *
+ * Page fault handling: When HV handles page fault of a page belonging
+ * to secure guest, it sends that to UV with a 64K UV_PAGE_IN request.
+ * Using 64K size is correct here too as UV would have split the 2MB page
+ * into 64k mappings and would have done page-outs earlier.
+ *
+ * In summary, the current secure pages handling code in HV assumes
+ * 64K page size and in fact fails any page-in/page-out requests of
+ * non-64K size upfront. If and when UV starts supporting multiple
+ * page-sizes, we need to break this assumption.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/migrate.h>
+#include <linux/kvm_host.h>
+#include <linux/ksm.h>
+#include <asm/ultravisor.h>
+#include <asm/mman.h>
+#include <asm/kvm_ppc.h>
+#include <asm/kvm_book3s_uvmem.h>
+
+static struct dev_pagemap kvmppc_uvmem_pgmap;
+static unsigned long *kvmppc_uvmem_bitmap;
+static DEFINE_SPINLOCK(kvmppc_uvmem_bitmap_lock);
+
+/*
+ * States of a GFN
+ * ---------------
+ * The GFN can be in one of the following states.
+ *
+ * (a) Secure - The GFN is secure. The GFN is associated with
+ * a Secure VM, the contents of the GFN is not accessible
+ * to the Hypervisor. This GFN can be backed by a secure-PFN,
+ * or can be backed by a normal-PFN with contents encrypted.
+ * The former is true when the GFN is paged-in into the
+ * ultravisor. The latter is true when the GFN is paged-out
+ * of the ultravisor.
+ *
+ * (b) Shared - The GFN is shared. The GFN is associated with a
+ * a secure VM. The contents of the GFN is accessible to
+ * Hypervisor. This GFN is backed by a normal-PFN and its
+ * content is un-encrypted.
+ *
+ * (c) Normal - The GFN is a normal. The GFN is associated with
+ * a normal VM. The contents of the GFN is accesible to
+ * the Hypervisor. Its content is never encrypted.
+ *
+ * States of a VM.
+ * ---------------
+ *
+ * Normal VM: A VM whose contents are always accessible to
+ * the hypervisor. All its GFNs are normal-GFNs.
+ *
+ * Secure VM: A VM whose contents are not accessible to the
+ * hypervisor without the VM's consent. Its GFNs are
+ * either Shared-GFN or Secure-GFNs.
+ *
+ * Transient VM: A Normal VM that is transitioning to secure VM.
+ * The transition starts on successful return of
+ * H_SVM_INIT_START, and ends on successful return
+ * of H_SVM_INIT_DONE. This transient VM, can have GFNs
+ * in any of the three states; i.e Secure-GFN, Shared-GFN,
+ * and Normal-GFN. The VM never executes in this state
+ * in supervisor-mode.
+ *
+ * Memory slot State.
+ * -----------------------------
+ * The state of a memory slot mirrors the state of the
+ * VM the memory slot is associated with.
+ *
+ * VM State transition.
+ * --------------------
+ *
+ * A VM always starts in Normal Mode.
+ *
+ * H_SVM_INIT_START moves the VM into transient state. During this
+ * time the Ultravisor may request some of its GFNs to be shared or
+ * secured. So its GFNs can be in one of the three GFN states.
+ *
+ * H_SVM_INIT_DONE moves the VM entirely from transient state to
+ * secure-state. At this point any left-over normal-GFNs are
+ * transitioned to Secure-GFN.
+ *
+ * H_SVM_INIT_ABORT moves the transient VM back to normal VM.
+ * All its GFNs are moved to Normal-GFNs.
+ *
+ * UV_TERMINATE transitions the secure-VM back to normal-VM. All
+ * the secure-GFN and shared-GFNs are tranistioned to normal-GFN
+ * Note: The contents of the normal-GFN is undefined at this point.
+ *
+ * GFN state implementation:
+ * -------------------------
+ *
+ * Secure GFN is associated with a secure-PFN; also called uvmem_pfn,
+ * when the GFN is paged-in. Its pfn[] has KVMPPC_GFN_UVMEM_PFN flag
+ * set, and contains the value of the secure-PFN.
+ * It is associated with a normal-PFN; also called mem_pfn, when
+ * the GFN is pagedout. Its pfn[] has KVMPPC_GFN_MEM_PFN flag set.
+ * The value of the normal-PFN is not tracked.
+ *
+ * Shared GFN is associated with a normal-PFN. Its pfn[] has
+ * KVMPPC_UVMEM_SHARED_PFN flag set. The value of the normal-PFN
+ * is not tracked.
+ *
+ * Normal GFN is associated with normal-PFN. Its pfn[] has
+ * no flag set. The value of the normal-PFN is not tracked.
+ *
+ * Life cycle of a GFN
+ * --------------------
+ *
+ * --------------------------------------------------------------
+ * | | Share | Unshare | SVM |H_SVM_INIT_DONE|
+ * | |operation |operation | abort/ | |
+ * | | | | terminate | |
+ * -------------------------------------------------------------
+ * | | | | | |
+ * | Secure | Shared | Secure |Normal |Secure |
+ * | | | | | |
+ * | Shared | Shared | Secure |Normal |Shared |
+ * | | | | | |
+ * | Normal | Shared | Secure |Normal |Secure |
+ * --------------------------------------------------------------
+ *
+ * Life cycle of a VM
+ * --------------------
+ *
+ * --------------------------------------------------------------------
+ * | | start | H_SVM_ |H_SVM_ |H_SVM_ |UV_SVM_ |
+ * | | VM |INIT_START|INIT_DONE|INIT_ABORT |TERMINATE |
+ * | | | | | | |
+ * --------- ----------------------------------------------------------
+ * | | | | | | |
+ * | Normal | Normal | Transient|Error |Error |Normal |
+ * | | | | | | |
+ * | Secure | Error | Error |Error |Error |Normal |
+ * | | | | | | |
+ * |Transient| N/A | Error |Secure |Normal |Normal |
+ * --------------------------------------------------------------------
+ */
+
+#define KVMPPC_GFN_UVMEM_PFN (1UL << 63)
+#define KVMPPC_GFN_MEM_PFN (1UL << 62)
+#define KVMPPC_GFN_SHARED (1UL << 61)
+#define KVMPPC_GFN_SECURE (KVMPPC_GFN_UVMEM_PFN | KVMPPC_GFN_MEM_PFN)
+#define KVMPPC_GFN_FLAG_MASK (KVMPPC_GFN_SECURE | KVMPPC_GFN_SHARED)
+#define KVMPPC_GFN_PFN_MASK (~KVMPPC_GFN_FLAG_MASK)
+
+struct kvmppc_uvmem_slot {
+ struct list_head list;
+ unsigned long nr_pfns;
+ unsigned long base_pfn;
+ unsigned long *pfns;
+};
+struct kvmppc_uvmem_page_pvt {
+ struct kvm *kvm;
+ unsigned long gpa;
+ bool skip_page_out;
+ bool remove_gfn;
+};
+
+bool kvmppc_uvmem_available(void)
+{
+ /*
+ * If kvmppc_uvmem_bitmap != NULL, then there is an ultravisor
+ * and our data structures have been initialized successfully.
+ */
+ return !!kvmppc_uvmem_bitmap;
+}
+
+int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
+{
+ struct kvmppc_uvmem_slot *p;
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ p->pfns = vzalloc(array_size(slot->npages, sizeof(*p->pfns)));
+ if (!p->pfns) {
+ kfree(p);
+ return -ENOMEM;
+ }
+ p->nr_pfns = slot->npages;
+ p->base_pfn = slot->base_gfn;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ list_add(&p->list, &kvm->arch.uvmem_pfns);
+ mutex_unlock(&kvm->arch.uvmem_lock);
+
+ return 0;
+}
+
+/*
+ * All device PFNs are already released by the time we come here.
+ */
+void kvmppc_uvmem_slot_free(struct kvm *kvm, const struct kvm_memory_slot *slot)
+{
+ struct kvmppc_uvmem_slot *p, *next;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ list_for_each_entry_safe(p, next, &kvm->arch.uvmem_pfns, list) {
+ if (p->base_pfn == slot->base_gfn) {
+ vfree(p->pfns);
+ list_del(&p->list);
+ kfree(p);
+ break;
+ }
+ }
+ mutex_unlock(&kvm->arch.uvmem_lock);
+}
+
+static void kvmppc_mark_gfn(unsigned long gfn, struct kvm *kvm,
+ unsigned long flag, unsigned long uvmem_pfn)
+{
+ struct kvmppc_uvmem_slot *p;
+
+ list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
+ if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
+ unsigned long index = gfn - p->base_pfn;
+
+ if (flag == KVMPPC_GFN_UVMEM_PFN)
+ p->pfns[index] = uvmem_pfn | flag;
+ else
+ p->pfns[index] = flag;
+ return;
+ }
+ }
+}
+
+/* mark the GFN as secure-GFN associated with @uvmem pfn device-PFN. */
+static void kvmppc_gfn_secure_uvmem_pfn(unsigned long gfn,
+ unsigned long uvmem_pfn, struct kvm *kvm)
+{
+ kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_UVMEM_PFN, uvmem_pfn);
+}
+
+/* mark the GFN as secure-GFN associated with a memory-PFN. */
+static void kvmppc_gfn_secure_mem_pfn(unsigned long gfn, struct kvm *kvm)
+{
+ kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_MEM_PFN, 0);
+}
+
+/* mark the GFN as a shared GFN. */
+static void kvmppc_gfn_shared(unsigned long gfn, struct kvm *kvm)
+{
+ kvmppc_mark_gfn(gfn, kvm, KVMPPC_GFN_SHARED, 0);
+}
+
+/* mark the GFN as a non-existent GFN. */
+static void kvmppc_gfn_remove(unsigned long gfn, struct kvm *kvm)
+{
+ kvmppc_mark_gfn(gfn, kvm, 0, 0);
+}
+
+/* return true, if the GFN is a secure-GFN backed by a secure-PFN */
+static bool kvmppc_gfn_is_uvmem_pfn(unsigned long gfn, struct kvm *kvm,
+ unsigned long *uvmem_pfn)
+{
+ struct kvmppc_uvmem_slot *p;
+
+ list_for_each_entry(p, &kvm->arch.uvmem_pfns, list) {
+ if (gfn >= p->base_pfn && gfn < p->base_pfn + p->nr_pfns) {
+ unsigned long index = gfn - p->base_pfn;
+
+ if (p->pfns[index] & KVMPPC_GFN_UVMEM_PFN) {
+ if (uvmem_pfn)
+ *uvmem_pfn = p->pfns[index] &
+ KVMPPC_GFN_PFN_MASK;
+ return true;
+ } else
+ return false;
+ }
+ }
+ return false;
+}
+
+/*
+ * starting from *gfn search for the next available GFN that is not yet
+ * transitioned to a secure GFN. return the value of that GFN in *gfn. If a
+ * GFN is found, return true, else return false
+ *
+ * Must be called with kvm->arch.uvmem_lock held.
+ */
+static bool kvmppc_next_nontransitioned_gfn(const struct kvm_memory_slot *memslot,
+ struct kvm *kvm, unsigned long *gfn)
+{
+ struct kvmppc_uvmem_slot *p = NULL, *iter;
+ bool ret = false;
+ unsigned long i;
+
+ list_for_each_entry(iter, &kvm->arch.uvmem_pfns, list)
+ if (*gfn >= iter->base_pfn && *gfn < iter->base_pfn + iter->nr_pfns) {
+ p = iter;
+ break;
+ }
+ if (!p)
+ return ret;
+ /*
+ * The code below assumes, one to one correspondence between
+ * kvmppc_uvmem_slot and memslot.
+ */
+ for (i = *gfn; i < p->base_pfn + p->nr_pfns; i++) {
+ unsigned long index = i - p->base_pfn;
+
+ if (!(p->pfns[index] & KVMPPC_GFN_FLAG_MASK)) {
+ *gfn = i;
+ ret = true;
+ break;
+ }
+ }
+ return ret;
+}
+
+static int kvmppc_memslot_page_merge(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot, bool merge)
+{
+ unsigned long gfn = memslot->base_gfn;
+ unsigned long end, start = gfn_to_hva(kvm, gfn);
+ int ret = 0;
+ struct vm_area_struct *vma;
+ int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE;
+
+ if (kvm_is_error_hva(start))
+ return H_STATE;
+
+ end = start + (memslot->npages << PAGE_SHIFT);
+
+ mmap_write_lock(kvm->mm);
+ do {
+ vma = find_vma_intersection(kvm->mm, start, end);
+ if (!vma) {
+ ret = H_STATE;
+ break;
+ }
+ ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
+ merge_flag, &vma->vm_flags);
+ if (ret) {
+ ret = H_STATE;
+ break;
+ }
+ start = vma->vm_end;
+ } while (end > vma->vm_end);
+
+ mmap_write_unlock(kvm->mm);
+ return ret;
+}
+
+static void __kvmppc_uvmem_memslot_delete(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot)
+{
+ uv_unregister_mem_slot(kvm->arch.lpid, memslot->id);
+ kvmppc_uvmem_slot_free(kvm, memslot);
+ kvmppc_memslot_page_merge(kvm, memslot, true);
+}
+
+static int __kvmppc_uvmem_memslot_create(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot)
+{
+ int ret = H_PARAMETER;
+
+ if (kvmppc_memslot_page_merge(kvm, memslot, false))
+ return ret;
+
+ if (kvmppc_uvmem_slot_init(kvm, memslot))
+ goto out1;
+
+ ret = uv_register_mem_slot(kvm->arch.lpid,
+ memslot->base_gfn << PAGE_SHIFT,
+ memslot->npages * PAGE_SIZE,
+ 0, memslot->id);
+ if (ret < 0) {
+ ret = H_PARAMETER;
+ goto out;
+ }
+ return 0;
+out:
+ kvmppc_uvmem_slot_free(kvm, memslot);
+out1:
+ kvmppc_memslot_page_merge(kvm, memslot, true);
+ return ret;
+}
+
+unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
+{
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot, *m;
+ int ret = H_SUCCESS;
+ int srcu_idx;
+
+ kvm->arch.secure_guest = KVMPPC_SECURE_INIT_START;
+
+ if (!kvmppc_uvmem_bitmap)
+ return H_UNSUPPORTED;
+
+ /* Only radix guests can be secure guests */
+ if (!kvm_is_radix(kvm))
+ return H_UNSUPPORTED;
+
+ /* NAK the transition to secure if not enabled */
+ if (!kvm->arch.svm_enabled)
+ return H_AUTHORITY;
+
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ /* register the memslot */
+ slots = kvm_memslots(kvm);
+ kvm_for_each_memslot(memslot, slots) {
+ ret = __kvmppc_uvmem_memslot_create(kvm, memslot);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ slots = kvm_memslots(kvm);
+ kvm_for_each_memslot(m, slots) {
+ if (m == memslot)
+ break;
+ __kvmppc_uvmem_memslot_delete(kvm, memslot);
+ }
+ }
+
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ return ret;
+}
+
+/*
+ * Provision a new page on HV side and copy over the contents
+ * from secure memory using UV_PAGE_OUT uvcall.
+ * Caller must held kvm->arch.uvmem_lock.
+ */
+static int __kvmppc_svm_page_out(struct vm_area_struct *vma,
+ unsigned long start,
+ unsigned long end, unsigned long page_shift,
+ struct kvm *kvm, unsigned long gpa)
+{
+ unsigned long src_pfn, dst_pfn = 0;
+ struct migrate_vma mig;
+ struct page *dpage, *spage;
+ struct kvmppc_uvmem_page_pvt *pvt;
+ unsigned long pfn;
+ int ret = U_SUCCESS;
+
+ memset(&mig, 0, sizeof(mig));
+ mig.vma = vma;
+ mig.start = start;
+ mig.end = end;
+ mig.src = &src_pfn;
+ mig.dst = &dst_pfn;
+ mig.pgmap_owner = &kvmppc_uvmem_pgmap;
+ mig.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+
+ /* The requested page is already paged-out, nothing to do */
+ if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
+ return ret;
+
+ ret = migrate_vma_setup(&mig);
+ if (ret)
+ return -1;
+
+ spage = migrate_pfn_to_page(*mig.src);
+ if (!spage || !(*mig.src & MIGRATE_PFN_MIGRATE))
+ goto out_finalize;
+
+ if (!is_zone_device_page(spage))
+ goto out_finalize;
+
+ dpage = alloc_page_vma(GFP_HIGHUSER, vma, start);
+ if (!dpage) {
+ ret = -1;
+ goto out_finalize;
+ }
+
+ lock_page(dpage);
+ pvt = spage->zone_device_data;
+ pfn = page_to_pfn(dpage);
+
+ /*
+ * This function is used in two cases:
+ * - When HV touches a secure page, for which we do UV_PAGE_OUT
+ * - When a secure page is converted to shared page, we *get*
+ * the page to essentially unmap the device page. In this
+ * case we skip page-out.
+ */
+ if (!pvt->skip_page_out)
+ ret = uv_page_out(kvm->arch.lpid, pfn << page_shift,
+ gpa, 0, page_shift);
+
+ if (ret == U_SUCCESS)
+ *mig.dst = migrate_pfn(pfn) | MIGRATE_PFN_LOCKED;
+ else {
+ unlock_page(dpage);
+ __free_page(dpage);
+ goto out_finalize;
+ }
+
+ migrate_vma_pages(&mig);
+
+out_finalize:
+ migrate_vma_finalize(&mig);
+ return ret;
+}
+
+static inline int kvmppc_svm_page_out(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ unsigned long page_shift,
+ struct kvm *kvm, unsigned long gpa)
+{
+ int ret;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ ret = __kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa);
+ mutex_unlock(&kvm->arch.uvmem_lock);
+
+ return ret;
+}
+
+/*
+ * Drop device pages that we maintain for the secure guest
+ *
+ * We first mark the pages to be skipped from UV_PAGE_OUT when there
+ * is HV side fault on these pages. Next we *get* these pages, forcing
+ * fault on them, do fault time migration to replace the device PTEs in
+ * QEMU page table with normal PTEs from newly allocated pages.
+ */
+void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *slot,
+ struct kvm *kvm, bool skip_page_out)
+{
+ int i;
+ struct kvmppc_uvmem_page_pvt *pvt;
+ struct page *uvmem_page;
+ struct vm_area_struct *vma = NULL;
+ unsigned long uvmem_pfn, gfn;
+ unsigned long addr;
+
+ mmap_read_lock(kvm->mm);
+
+ addr = slot->userspace_addr;
+
+ gfn = slot->base_gfn;
+ for (i = slot->npages; i; --i, ++gfn, addr += PAGE_SIZE) {
+
+ /* Fetch the VMA if addr is not in the latest fetched one */
+ if (!vma || addr >= vma->vm_end) {
+ vma = find_vma_intersection(kvm->mm, addr, addr+1);
+ if (!vma) {
+ pr_err("Can't find VMA for gfn:0x%lx\n", gfn);
+ break;
+ }
+ }
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+
+ if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
+ uvmem_page = pfn_to_page(uvmem_pfn);
+ pvt = uvmem_page->zone_device_data;
+ pvt->skip_page_out = skip_page_out;
+ pvt->remove_gfn = true;
+
+ if (__kvmppc_svm_page_out(vma, addr, addr + PAGE_SIZE,
+ PAGE_SHIFT, kvm, pvt->gpa))
+ pr_err("Can't page out gpa:0x%lx addr:0x%lx\n",
+ pvt->gpa, addr);
+ } else {
+ /* Remove the shared flag if any */
+ kvmppc_gfn_remove(gfn, kvm);
+ }
+
+ mutex_unlock(&kvm->arch.uvmem_lock);
+ }
+
+ mmap_read_unlock(kvm->mm);
+}
+
+unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm)
+{
+ int srcu_idx;
+ struct kvm_memory_slot *memslot;
+
+ /*
+ * Expect to be called only after INIT_START and before INIT_DONE.
+ * If INIT_DONE was completed, use normal VM termination sequence.
+ */
+ if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
+ return H_UNSUPPORTED;
+
+ if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE)
+ return H_STATE;
+
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ kvm_for_each_memslot(memslot, kvm_memslots(kvm))
+ kvmppc_uvmem_drop_pages(memslot, kvm, false);
+
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+ kvm->arch.secure_guest = 0;
+ uv_svm_terminate(kvm->arch.lpid);
+
+ return H_PARAMETER;
+}
+
+/*
+ * Get a free device PFN from the pool
+ *
+ * Called when a normal page is moved to secure memory (UV_PAGE_IN). Device
+ * PFN will be used to keep track of the secure page on HV side.
+ *
+ * Called with kvm->arch.uvmem_lock held
+ */
+static struct page *kvmppc_uvmem_get_page(unsigned long gpa, struct kvm *kvm)
+{
+ struct page *dpage = NULL;
+ unsigned long bit, uvmem_pfn;
+ struct kvmppc_uvmem_page_pvt *pvt;
+ unsigned long pfn_last, pfn_first;
+
+ pfn_first = kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT;
+ pfn_last = pfn_first +
+ (range_len(&kvmppc_uvmem_pgmap.range) >> PAGE_SHIFT);
+
+ spin_lock(&kvmppc_uvmem_bitmap_lock);
+ bit = find_first_zero_bit(kvmppc_uvmem_bitmap,
+ pfn_last - pfn_first);
+ if (bit >= (pfn_last - pfn_first))
+ goto out;
+ bitmap_set(kvmppc_uvmem_bitmap, bit, 1);
+ spin_unlock(&kvmppc_uvmem_bitmap_lock);
+
+ pvt = kzalloc(sizeof(*pvt), GFP_KERNEL);
+ if (!pvt)
+ goto out_clear;
+
+ uvmem_pfn = bit + pfn_first;
+ kvmppc_gfn_secure_uvmem_pfn(gpa >> PAGE_SHIFT, uvmem_pfn, kvm);
+
+ pvt->gpa = gpa;
+ pvt->kvm = kvm;
+
+ dpage = pfn_to_page(uvmem_pfn);
+ dpage->zone_device_data = pvt;
+ get_page(dpage);
+ lock_page(dpage);
+ return dpage;
+out_clear:
+ spin_lock(&kvmppc_uvmem_bitmap_lock);
+ bitmap_clear(kvmppc_uvmem_bitmap, bit, 1);
+out:
+ spin_unlock(&kvmppc_uvmem_bitmap_lock);
+ return NULL;
+}
+
+/*
+ * Alloc a PFN from private device memory pool. If @pagein is true,
+ * copy page from normal memory to secure memory using UV_PAGE_IN uvcall.
+ */
+static int kvmppc_svm_page_in(struct vm_area_struct *vma,
+ unsigned long start,
+ unsigned long end, unsigned long gpa, struct kvm *kvm,
+ unsigned long page_shift,
+ bool pagein)
+{
+ unsigned long src_pfn, dst_pfn = 0;
+ struct migrate_vma mig;
+ struct page *spage;
+ unsigned long pfn;
+ struct page *dpage;
+ int ret = 0;
+
+ memset(&mig, 0, sizeof(mig));
+ mig.vma = vma;
+ mig.start = start;
+ mig.end = end;
+ mig.src = &src_pfn;
+ mig.dst = &dst_pfn;
+ mig.flags = MIGRATE_VMA_SELECT_SYSTEM;
+
+ ret = migrate_vma_setup(&mig);
+ if (ret)
+ return ret;
+
+ if (!(*mig.src & MIGRATE_PFN_MIGRATE)) {
+ ret = -1;
+ goto out_finalize;
+ }
+
+ dpage = kvmppc_uvmem_get_page(gpa, kvm);
+ if (!dpage) {
+ ret = -1;
+ goto out_finalize;
+ }
+
+ if (pagein) {
+ pfn = *mig.src >> MIGRATE_PFN_SHIFT;
+ spage = migrate_pfn_to_page(*mig.src);
+ if (spage) {
+ ret = uv_page_in(kvm->arch.lpid, pfn << page_shift,
+ gpa, 0, page_shift);
+ if (ret)
+ goto out_finalize;
+ }
+ }
+
+ *mig.dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
+ migrate_vma_pages(&mig);
+out_finalize:
+ migrate_vma_finalize(&mig);
+ return ret;
+}
+
+static int kvmppc_uv_migrate_mem_slot(struct kvm *kvm,
+ const struct kvm_memory_slot *memslot)
+{
+ unsigned long gfn = memslot->base_gfn;
+ struct vm_area_struct *vma;
+ unsigned long start, end;
+ int ret = 0;
+
+ mmap_read_lock(kvm->mm);
+ mutex_lock(&kvm->arch.uvmem_lock);
+ while (kvmppc_next_nontransitioned_gfn(memslot, kvm, &gfn)) {
+ ret = H_STATE;
+ start = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(start))
+ break;
+
+ end = start + (1UL << PAGE_SHIFT);
+ vma = find_vma_intersection(kvm->mm, start, end);
+ if (!vma || vma->vm_start > start || vma->vm_end < end)
+ break;
+
+ ret = kvmppc_svm_page_in(vma, start, end,
+ (gfn << PAGE_SHIFT), kvm, PAGE_SHIFT, false);
+ if (ret) {
+ ret = H_STATE;
+ break;
+ }
+
+ /* relinquish the cpu if needed */
+ cond_resched();
+ }
+ mutex_unlock(&kvm->arch.uvmem_lock);
+ mmap_read_unlock(kvm->mm);
+ return ret;
+}
+
+unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
+{
+ struct kvm_memslots *slots;
+ struct kvm_memory_slot *memslot;
+ int srcu_idx;
+ long ret = H_SUCCESS;
+
+ if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
+ return H_UNSUPPORTED;
+
+ /* migrate any unmoved normal pfn to device pfns*/
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+ slots = kvm_memslots(kvm);
+ kvm_for_each_memslot(memslot, slots) {
+ ret = kvmppc_uv_migrate_mem_slot(kvm, memslot);
+ if (ret) {
+ /*
+ * The pages will remain transitioned.
+ * Its the callers responsibility to
+ * terminate the VM, which will undo
+ * all state of the VM. Till then
+ * this VM is in a erroneous state.
+ * Its KVMPPC_SECURE_INIT_DONE will
+ * remain unset.
+ */
+ ret = H_STATE;
+ goto out;
+ }
+ }
+
+ kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
+ pr_info("LPID %d went secure\n", kvm->arch.lpid);
+
+out:
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ return ret;
+}
+
+/*
+ * Shares the page with HV, thus making it a normal page.
+ *
+ * - If the page is already secure, then provision a new page and share
+ * - If the page is a normal page, share the existing page
+ *
+ * In the former case, uses dev_pagemap_ops.migrate_to_ram handler
+ * to unmap the device page from QEMU's page tables.
+ */
+static unsigned long kvmppc_share_page(struct kvm *kvm, unsigned long gpa,
+ unsigned long page_shift)
+{
+
+ int ret = H_PARAMETER;
+ struct page *uvmem_page;
+ struct kvmppc_uvmem_page_pvt *pvt;
+ unsigned long pfn;
+ unsigned long gfn = gpa >> page_shift;
+ int srcu_idx;
+ unsigned long uvmem_pfn;
+
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+ mutex_lock(&kvm->arch.uvmem_lock);
+ if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
+ uvmem_page = pfn_to_page(uvmem_pfn);
+ pvt = uvmem_page->zone_device_data;
+ pvt->skip_page_out = true;
+ /*
+ * do not drop the GFN. It is a valid GFN
+ * that is transitioned to a shared GFN.
+ */
+ pvt->remove_gfn = false;
+ }
+
+retry:
+ mutex_unlock(&kvm->arch.uvmem_lock);
+ pfn = gfn_to_pfn(kvm, gfn);
+ if (is_error_noslot_pfn(pfn))
+ goto out;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
+ uvmem_page = pfn_to_page(uvmem_pfn);
+ pvt = uvmem_page->zone_device_data;
+ pvt->skip_page_out = true;
+ pvt->remove_gfn = false; /* it continues to be a valid GFN */
+ kvm_release_pfn_clean(pfn);
+ goto retry;
+ }
+
+ if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0,
+ page_shift)) {
+ kvmppc_gfn_shared(gfn, kvm);
+ ret = H_SUCCESS;
+ }
+ kvm_release_pfn_clean(pfn);
+ mutex_unlock(&kvm->arch.uvmem_lock);
+out:
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ return ret;
+}
+
+/*
+ * H_SVM_PAGE_IN: Move page from normal memory to secure memory.
+ *
+ * H_PAGE_IN_SHARED flag makes the page shared which means that the same
+ * memory in is visible from both UV and HV.
+ */
+unsigned long kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa,
+ unsigned long flags,
+ unsigned long page_shift)
+{
+ unsigned long start, end;
+ struct vm_area_struct *vma;
+ int srcu_idx;
+ unsigned long gfn = gpa >> page_shift;
+ int ret;
+
+ if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
+ return H_UNSUPPORTED;
+
+ if (page_shift != PAGE_SHIFT)
+ return H_P3;
+
+ if (flags & ~H_PAGE_IN_SHARED)
+ return H_P2;
+
+ if (flags & H_PAGE_IN_SHARED)
+ return kvmppc_share_page(kvm, gpa, page_shift);
+
+ ret = H_PARAMETER;
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+ mmap_read_lock(kvm->mm);
+
+ start = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(start))
+ goto out;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ /* Fail the page-in request of an already paged-in page */
+ if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
+ goto out_unlock;
+
+ end = start + (1UL << page_shift);
+ vma = find_vma_intersection(kvm->mm, start, end);
+ if (!vma || vma->vm_start > start || vma->vm_end < end)
+ goto out_unlock;
+
+ if (kvmppc_svm_page_in(vma, start, end, gpa, kvm, page_shift,
+ true))
+ goto out_unlock;
+
+ ret = H_SUCCESS;
+
+out_unlock:
+ mutex_unlock(&kvm->arch.uvmem_lock);
+out:
+ mmap_read_unlock(kvm->mm);
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ return ret;
+}
+
+
+/*
+ * Fault handler callback that gets called when HV touches any page that
+ * has been moved to secure memory, we ask UV to give back the page by
+ * issuing UV_PAGE_OUT uvcall.
+ *
+ * This eventually results in dropping of device PFN and the newly
+ * provisioned page/PFN gets populated in QEMU page tables.
+ */
+static vm_fault_t kvmppc_uvmem_migrate_to_ram(struct vm_fault *vmf)
+{
+ struct kvmppc_uvmem_page_pvt *pvt = vmf->page->zone_device_data;
+
+ if (kvmppc_svm_page_out(vmf->vma, vmf->address,
+ vmf->address + PAGE_SIZE, PAGE_SHIFT,
+ pvt->kvm, pvt->gpa))
+ return VM_FAULT_SIGBUS;
+ else
+ return 0;
+}
+
+/*
+ * Release the device PFN back to the pool
+ *
+ * Gets called when secure GFN tranistions from a secure-PFN
+ * to a normal PFN during H_SVM_PAGE_OUT.
+ * Gets called with kvm->arch.uvmem_lock held.
+ */
+static void kvmppc_uvmem_page_free(struct page *page)
+{
+ unsigned long pfn = page_to_pfn(page) -
+ (kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT);
+ struct kvmppc_uvmem_page_pvt *pvt;
+
+ spin_lock(&kvmppc_uvmem_bitmap_lock);
+ bitmap_clear(kvmppc_uvmem_bitmap, pfn, 1);
+ spin_unlock(&kvmppc_uvmem_bitmap_lock);
+
+ pvt = page->zone_device_data;
+ page->zone_device_data = NULL;
+ if (pvt->remove_gfn)
+ kvmppc_gfn_remove(pvt->gpa >> PAGE_SHIFT, pvt->kvm);
+ else
+ kvmppc_gfn_secure_mem_pfn(pvt->gpa >> PAGE_SHIFT, pvt->kvm);
+ kfree(pvt);
+}
+
+static const struct dev_pagemap_ops kvmppc_uvmem_ops = {
+ .page_free = kvmppc_uvmem_page_free,
+ .migrate_to_ram = kvmppc_uvmem_migrate_to_ram,
+};
+
+/*
+ * H_SVM_PAGE_OUT: Move page from secure memory to normal memory.
+ */
+unsigned long
+kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long gpa,
+ unsigned long flags, unsigned long page_shift)
+{
+ unsigned long gfn = gpa >> page_shift;
+ unsigned long start, end;
+ struct vm_area_struct *vma;
+ int srcu_idx;
+ int ret;
+
+ if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
+ return H_UNSUPPORTED;
+
+ if (page_shift != PAGE_SHIFT)
+ return H_P3;
+
+ if (flags)
+ return H_P2;
+
+ ret = H_PARAMETER;
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+ mmap_read_lock(kvm->mm);
+ start = gfn_to_hva(kvm, gfn);
+ if (kvm_is_error_hva(start))
+ goto out;
+
+ end = start + (1UL << page_shift);
+ vma = find_vma_intersection(kvm->mm, start, end);
+ if (!vma || vma->vm_start > start || vma->vm_end < end)
+ goto out;
+
+ if (!kvmppc_svm_page_out(vma, start, end, page_shift, kvm, gpa))
+ ret = H_SUCCESS;
+out:
+ mmap_read_unlock(kvm->mm);
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ return ret;
+}
+
+int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
+{
+ unsigned long pfn;
+ int ret = U_SUCCESS;
+
+ pfn = gfn_to_pfn(kvm, gfn);
+ if (is_error_noslot_pfn(pfn))
+ return -EFAULT;
+
+ mutex_lock(&kvm->arch.uvmem_lock);
+ if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
+ goto out;
+
+ ret = uv_page_in(kvm->arch.lpid, pfn << PAGE_SHIFT, gfn << PAGE_SHIFT,
+ 0, PAGE_SHIFT);
+out:
+ kvm_release_pfn_clean(pfn);
+ mutex_unlock(&kvm->arch.uvmem_lock);
+ return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
+}
+
+int kvmppc_uvmem_memslot_create(struct kvm *kvm, const struct kvm_memory_slot *new)
+{
+ int ret = __kvmppc_uvmem_memslot_create(kvm, new);
+
+ if (!ret)
+ ret = kvmppc_uv_migrate_mem_slot(kvm, new);
+
+ return ret;
+}
+
+void kvmppc_uvmem_memslot_delete(struct kvm *kvm, const struct kvm_memory_slot *old)
+{
+ __kvmppc_uvmem_memslot_delete(kvm, old);
+}
+
+static u64 kvmppc_get_secmem_size(void)
+{
+ struct device_node *np;
+ int i, len;
+ const __be32 *prop;
+ u64 size = 0;
+
+ /*
+ * First try the new ibm,secure-memory nodes which supersede the
+ * secure-memory-ranges property.
+ * If we found some, no need to read the deprecated ones.
+ */
+ for_each_compatible_node(np, NULL, "ibm,secure-memory") {
+ prop = of_get_property(np, "reg", &len);
+ if (!prop)
+ continue;
+ size += of_read_number(prop + 2, 2);
+ }
+ if (size)
+ return size;
+
+ np = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
+ if (!np)
+ goto out;
+
+ prop = of_get_property(np, "secure-memory-ranges", &len);
+ if (!prop)
+ goto out_put;
+
+ for (i = 0; i < len / (sizeof(*prop) * 4); i++)
+ size += of_read_number(prop + (i * 4) + 2, 2);
+
+out_put:
+ of_node_put(np);
+out:
+ return size;
+}
+
+int kvmppc_uvmem_init(void)
+{
+ int ret = 0;
+ unsigned long size;
+ struct resource *res;
+ void *addr;
+ unsigned long pfn_last, pfn_first;
+
+ size = kvmppc_get_secmem_size();
+ if (!size) {
+ /*
+ * Don't fail the initialization of kvm-hv module if
+ * the platform doesn't export ibm,uv-firmware node.
+ * Let normal guests run on such PEF-disabled platform.
+ */
+ pr_info("KVMPPC-UVMEM: No support for secure guests\n");
+ goto out;
+ }
+
+ res = request_free_mem_region(&iomem_resource, size, "kvmppc_uvmem");
+ if (IS_ERR(res)) {
+ ret = PTR_ERR(res);
+ goto out;
+ }
+
+ kvmppc_uvmem_pgmap.type = MEMORY_DEVICE_PRIVATE;
+ kvmppc_uvmem_pgmap.range.start = res->start;
+ kvmppc_uvmem_pgmap.range.end = res->end;
+ kvmppc_uvmem_pgmap.nr_range = 1;
+ kvmppc_uvmem_pgmap.ops = &kvmppc_uvmem_ops;
+ /* just one global instance: */
+ kvmppc_uvmem_pgmap.owner = &kvmppc_uvmem_pgmap;
+ addr = memremap_pages(&kvmppc_uvmem_pgmap, NUMA_NO_NODE);
+ if (IS_ERR(addr)) {
+ ret = PTR_ERR(addr);
+ goto out_free_region;
+ }
+
+ pfn_first = res->start >> PAGE_SHIFT;
+ pfn_last = pfn_first + (resource_size(res) >> PAGE_SHIFT);
+ kvmppc_uvmem_bitmap = kcalloc(BITS_TO_LONGS(pfn_last - pfn_first),
+ sizeof(unsigned long), GFP_KERNEL);
+ if (!kvmppc_uvmem_bitmap) {
+ ret = -ENOMEM;
+ goto out_unmap;
+ }
+
+ pr_info("KVMPPC-UVMEM: Secure Memory size 0x%lx\n", size);
+ return ret;
+out_unmap:
+ memunmap_pages(&kvmppc_uvmem_pgmap);
+out_free_region:
+ release_mem_region(res->start, size);
+out:
+ return ret;
+}
+
+void kvmppc_uvmem_free(void)
+{
+ if (!kvmppc_uvmem_bitmap)
+ return;
+
+ memunmap_pages(&kvmppc_uvmem_pgmap);
+ release_mem_region(kvmppc_uvmem_pgmap.range.start,
+ range_len(&kvmppc_uvmem_pgmap.range));
+ kfree(kvmppc_uvmem_bitmap);
+}