linux_dsm_epyc7002/arch/powerpc/kvm/book3s_hv_uvmem.c

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KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
// 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.
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
*/
/*
* 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_sem - 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.
*
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
* 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>
static struct dev_pagemap kvmppc_uvmem_pgmap;
static unsigned long *kvmppc_uvmem_bitmap;
static DEFINE_SPINLOCK(kvmppc_uvmem_bitmap_lock);
#define KVMPPC_UVMEM_PFN (1UL << 63)
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;
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
};
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_uvmem_pfn_insert(unsigned long gfn, unsigned long uvmem_pfn,
struct kvm *kvm)
{
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;
p->pfns[index] = uvmem_pfn | KVMPPC_UVMEM_PFN;
return;
}
}
}
static void kvmppc_uvmem_pfn_remove(unsigned long gfn, struct kvm *kvm)
{
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) {
p->pfns[gfn - p->base_pfn] = 0;
return;
}
}
}
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_UVMEM_PFN) {
if (uvmem_pfn)
*uvmem_pfn = p->pfns[index] &
~KVMPPC_UVMEM_PFN;
return true;
} else
return false;
}
}
return false;
}
unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int ret = H_SUCCESS;
int srcu_idx;
if (!kvmppc_uvmem_bitmap)
return H_UNSUPPORTED;
/* Only radix guests can be secure guests */
if (!kvm_is_radix(kvm))
return H_UNSUPPORTED;
srcu_idx = srcu_read_lock(&kvm->srcu);
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, slots) {
if (kvmppc_uvmem_slot_init(kvm, memslot)) {
ret = H_PARAMETER;
goto out;
}
ret = uv_register_mem_slot(kvm->arch.lpid,
memslot->base_gfn << PAGE_SHIFT,
memslot->npages * PAGE_SIZE,
0, memslot->id);
if (ret < 0) {
kvmppc_uvmem_slot_free(kvm, memslot);
ret = H_PARAMETER;
goto out;
}
}
kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_START;
out:
srcu_read_unlock(&kvm->srcu, srcu_idx);
return ret;
}
unsigned long kvmppc_h_svm_init_done(struct kvm *kvm)
{
if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START))
return H_UNSUPPORTED;
kvm->arch.secure_guest |= KVMPPC_SECURE_INIT_DONE;
pr_info("LPID %d went secure\n", kvm->arch.lpid);
return H_SUCCESS;
}
/*
* 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 *free,
struct kvm *kvm, bool skip_page_out)
{
int i;
struct kvmppc_uvmem_page_pvt *pvt;
unsigned long pfn, uvmem_pfn;
unsigned long gfn = free->base_gfn;
for (i = free->npages; i; --i, ++gfn) {
struct page *uvmem_page;
mutex_lock(&kvm->arch.uvmem_lock);
if (!kvmppc_gfn_is_uvmem_pfn(gfn, kvm, &uvmem_pfn)) {
mutex_unlock(&kvm->arch.uvmem_lock);
continue;
}
uvmem_page = pfn_to_page(uvmem_pfn);
pvt = uvmem_page->zone_device_data;
pvt->skip_page_out = skip_page_out;
mutex_unlock(&kvm->arch.uvmem_lock);
pfn = gfn_to_pfn(kvm, gfn);
if (is_error_noslot_pfn(pfn))
continue;
kvm_release_pfn_clean(pfn);
}
}
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;
}
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
/*
* 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.res.start >> PAGE_SHIFT;
pfn_last = pfn_first +
(resource_size(&kvmppc_uvmem_pgmap.res) >> 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_uvmem_pfn_insert(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 and 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 *downgrade)
{
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;
/*
* We come here with mmap_sem write lock held just for
* ksm_madvise(), otherwise we only need read mmap_sem.
* Hence downgrade to read lock once ksm_madvise() is done.
*/
ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
MADV_UNMERGEABLE, &vma->vm_flags);
downgrade_write(&kvm->mm->mmap_sem);
*downgrade = true;
if (ret)
return ret;
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;
}
pfn = *mig.src >> MIGRATE_PFN_SHIFT;
spage = migrate_pfn_to_page(*mig.src);
if (spage)
uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0,
page_shift);
*mig.dst = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
migrate_vma_pages(&mig);
out_finalize:
migrate_vma_finalize(&mig);
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;
}
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;
kvm_release_pfn_clean(pfn);
goto retry;
}
if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, page_shift))
ret = H_SUCCESS;
kvm_release_pfn_clean(pfn);
mutex_unlock(&kvm->arch.uvmem_lock);
out:
srcu_read_unlock(&kvm->srcu, srcu_idx);
return ret;
}
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
/*
* 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.
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
*/
unsigned long
kvmppc_h_svm_page_in(struct kvm *kvm, unsigned long gpa,
unsigned long flags, unsigned long page_shift)
{
bool downgrade = false;
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)
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
return H_P2;
if (flags & H_PAGE_IN_SHARED)
return kvmppc_share_page(kvm, gpa, page_shift);
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
ret = H_PARAMETER;
srcu_idx = srcu_read_lock(&kvm->srcu);
down_write(&kvm->mm->mmap_sem);
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,
&downgrade))
ret = H_SUCCESS;
out_unlock:
mutex_unlock(&kvm->arch.uvmem_lock);
out:
if (downgrade)
up_read(&kvm->mm->mmap_sem);
else
up_write(&kvm->mm->mmap_sem);
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.
*/
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;
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
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;
mutex_lock(&kvm->arch.uvmem_lock);
/* The requested page is already paged-out, nothing to do */
if (!kvmppc_gfn_is_uvmem_pfn(gpa >> page_shift, kvm, NULL))
goto out;
ret = migrate_vma_setup(&mig);
if (ret)
goto out;
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
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;
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
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);
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
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);
out:
mutex_unlock(&kvm->arch.uvmem_lock);
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 page becomes a normal page 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.res.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;
kvmppc_uvmem_pfn_remove(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);
down_read(&kvm->mm->mmap_sem);
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:
up_read(&kvm->mm->mmap_sem);
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;
}
KVM: PPC: Book3S HV: Support for running secure guests 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). HV is informed about the guest's transition to secure mode via hcalls: H_SVM_INIT_START: Initiate securing a VM H_SVM_INIT_DONE: Conclude securing a VM As part of H_SVM_INIT_START, register all existing memslots with the UV. H_SVM_INIT_DONE call by UV informs HV that transition of the guest to secure mode is complete. These two states (transition to secure mode STARTED and transition to secure mode COMPLETED) are recorded in kvm->arch.secure_guest. Setting these states will cause the assembly code that enters the guest to call the UV_RETURN ucall instead of trying to enter the guest directly. Migration of pages betwen normal and secure memory of secure guest is implemented in H_SVM_PAGE_IN and H_SVM_PAGE_OUT hcalls. H_SVM_PAGE_IN: Move the content of a normal page to secure page H_SVM_PAGE_OUT: Move the content of a secure page to normal page Private ZONE_DEVICE memory equal to the amount of secure memory available in the platform for running secure guests is created. 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. The movement of pages between normal and secure memory is done via migrate_vma_pages() using UV_PAGE_IN and UV_PAGE_OUT ucalls. In order to prevent the device private pages (that correspond to pages of secure guest) from participating in KSM merging, H_SVM_PAGE_IN calls ksm_madvise() under read version of mmap_sem. However ksm_madvise() needs to be under write lock. Hence we call kvmppc_svm_page_in with mmap_sem held for writing, and it then downgrades to a read lock after calling ksm_madvise. [paulus@ozlabs.org - roll in patch "KVM: PPC: Book3S HV: Take write mmap_sem when calling ksm_madvise"] Signed-off-by: Bharata B Rao <bharata@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2019-11-25 10:06:26 +07:00
static u64 kvmppc_get_secmem_size(void)
{
struct device_node *np;
int i, len;
const __be32 *prop;
u64 size = 0;
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.res = *res;
kvmppc_uvmem_pgmap.ops = &kvmppc_uvmem_ops;
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)
{
memunmap_pages(&kvmppc_uvmem_pgmap);
release_mem_region(kvmppc_uvmem_pgmap.res.start,
resource_size(&kvmppc_uvmem_pgmap.res));
kfree(kvmppc_uvmem_bitmap);
}