Page-merging of pages in memory-slots associated with a Secure VM,
is disabled in H_SVM_PAGE_IN handler.
This operation should have been done the much earlier; the moment the VM
is initiated for secure-transition. Delaying this operation, increases
the probability for those pages to acquire new references , making it
impossible to migrate those pages in H_SVM_PAGE_IN handler.
Disable page-migration in H_SVM_INIT_START handling.
Reviewed-by: Bharata B Rao <bhar...@linux.ibm.com>
Signed-off-by: Ram Pai <linux...@us.ibm.com>
---
Documentation/powerpc/ultravisor.rst | 1 +
arch/powerpc/kvm/book3s_hv_uvmem.c | 123 +++++++++++++++++++++++++----------
2 files changed, 89 insertions(+), 35 deletions(-)
diff --git a/Documentation/powerpc/ultravisor.rst
b/Documentation/powerpc/ultravisor.rst
index df136c8..a1c8c37 100644
--- a/Documentation/powerpc/ultravisor.rst
+++ b/Documentation/powerpc/ultravisor.rst
@@ -895,6 +895,7 @@ Return values
One of the following values:
* H_SUCCESS on success.
+ * H_STATE if the VM is not in a position to switch to secure.
Description
~~~~~~~~~~~
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c
b/arch/powerpc/kvm/book3s_hv_uvmem.c
index e6f76bc..533b608 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -211,10 +211,79 @@ static bool kvmppc_gfn_is_uvmem_pfn(unsigned long gfn,
struct kvm *kvm,
return false;
}
+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;
+ struct kvm_memory_slot *memslot, *m;
int ret = H_SUCCESS;
int srcu_idx;
@@ -232,23 +301,24 @@ unsigned long kvmppc_h_svm_init_start(struct kvm *kvm)
return H_AUTHORITY;
srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ /* register the memslot */
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;
+ 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);
}
}
-out:
+
srcu_read_unlock(&kvm->srcu, srcu_idx);
return ret;
}
@@ -384,7 +454,7 @@ static struct page *kvmppc_uvmem_get_page(unsigned long
gpa, struct kvm *kvm)
*/
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 page_shift)
{
unsigned long src_pfn, dst_pfn = 0;
struct migrate_vma mig;
@@ -400,18 +470,6 @@ static int kvmppc_svm_page_in(struct vm_area_struct *vma,
unsigned long start,
mig.src = &src_pfn;
mig.dst = &dst_pfn;
- /*
- * We come here with mmap_lock write lock held just for
- * ksm_madvise(), otherwise we only need read mmap_lock.
- * 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);
- mmap_write_downgrade(kvm->mm);
- *downgrade = true;
- if (ret)
- return ret;
-
ret = migrate_vma_setup(&mig);
if (ret)
return ret;
@@ -503,7 +561,6 @@ 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;
@@ -524,7 +581,7 @@ unsigned long kvmppc_h_svm_page_in(struct kvm *kvm,
unsigned long gpa,
ret = H_PARAMETER;
srcu_idx = srcu_read_lock(&kvm->srcu);
- mmap_write_lock(kvm->mm);
+ mmap_read_lock(kvm->mm);
start = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(start))
@@ -540,16 +597,12 @@ unsigned long kvmppc_h_svm_page_in(struct kvm *kvm,
unsigned long gpa,
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))
+ if (!kvmppc_svm_page_in(vma, start, end, gpa, kvm, page_shift))
ret = H_SUCCESS;
out_unlock:
mutex_unlock(&kvm->arch.uvmem_lock);
out:
- if (downgrade)
- mmap_read_unlock(kvm->mm);
- else
- mmap_write_unlock(kvm->mm);
+ mmap_read_unlock(kvm->mm);
srcu_read_unlock(&kvm->srcu, srcu_idx);
return ret;
}
--
1.8.3.1
