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linux-sg2042/arch/powerpc/kvm/book3s_hv_uvmem.c

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// 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;
bool ret = false;
unsigned long i;
list_for_each_entry(p, &kvm->arch.uvmem_pfns, list)
if (*gfn >= p->base_pfn && *gfn < p->base_pfn + p->nr_pfns)
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);
}
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