[Patch v2 0/4] Defer page pinning for SEV guests until guest pages touched

[Patch v2 0/4] Defer page pinning for SEV guests until guest pages touched

[eric van tassell]

Overview
========
	Defer pinning of the guest's pages until nested page faults occur
	to improve startup time and reduce memory pressure for SEV guests.

	Cease paying the computational cost of pinning all pages when an
	encrypted region is registered, before it is known if they will be accessed.

	Cease creating the memory pressure due to  pinning all pages when an
	encrypted region is registered before, it is known if they will be accessed.

Timing Results
==========
All timings are done by hand with and Android stopwatch app

SEV guest size(GiB)  	     |  4 |  8 | 16 | 32 | 60 |
without patch series(sec)    |  2 |  3 |  4 |  8 | 14 |
with patch series (sec)      |  1 |  1 |  1 |  1 |  1 |

Patch Series Changelog
==============
	1 -> 2:
		* mmio checks move from sev_pin_page() to caller and the
		  set_spte_notify* symbols are renamed to pin_page().

		* sev_get_page() warns on failures which should not happen.
		
		* kvm->srcu is used to avoid any possibility of a race in
		  sev_launch_update_data()
Applies To:
===========
	This patch applies top of this commit from the <next> branch of
	the kvm tree:
	    c34b26b98cac   Tianjia Zhang : KVM: MIPS: clean up redundant 'kvm_run' parameters

eric van tassell (4):
  KVM:MMU: Introduce the pin_page() callback
  KVM:SVM: Implement pin_page support
  KVM:SVM: Pin sev_launch_update_data() pages via sev_get_page()
  KVM:SVM: Remove struct enc_region and associated pinned page tracking.

 arch/x86/include/asm/kvm_host.h |   3 +
 arch/x86/kvm/mmu/mmu.c          |  30 +++-
 arch/x86/kvm/mmu/paging_tmpl.h  |  27 ++--
 arch/x86/kvm/svm/sev.c          | 238 +++++++++++++++++---------------
 arch/x86/kvm/svm/svm.c          |   2 +
 arch/x86/kvm/svm/svm.h          |   4 +-
 6 files changed, 174 insertions(+), 130 deletions(-)

-- 
2.17.1

[Patch v2 1/4] KVM:MMU: Introduce the pin_page() callback

[eric van tassell]

This generic callback will be called just before setting the spte.

Check the return code where not previously checked since this operation can
return an error.

Defer pinning of SEV guest pages until they're used in order to reduce SEV
guest startup time by eliminating the compute cycles required to pin all
the pages up front. Additionally, we want to reduce memory pressure due to
guests that reserve but only sparsely access a large amount of memory.

Co-developed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: eric van tassell <Eric.VanTassell@amd.com>
---
 arch/x86/include/asm/kvm_host.h |  3 +++
 arch/x86/kvm/mmu/mmu.c          | 30 ++++++++++++++++++++++++++----
 arch/x86/kvm/mmu/paging_tmpl.h  | 27 ++++++++++++++++-----------
 3 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5aaef036627f..767653fa3245 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1227,6 +1227,9 @@ struct kvm_x86_ops {
 	int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
 
 	void (*migrate_timers)(struct kvm_vcpu *vcpu);
+
+	int (*pin_page)(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn,
+			int level, u64 *spte);
 };
 
 struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index fa506aaaf019..2b60fdb79b86 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3004,6 +3004,22 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 		spte |= kvm_x86_ops.get_mt_mask(vcpu, gfn,
 			kvm_is_mmio_pfn(pfn));
 
+	if (kvm_x86_ops.pin_page && !kvm_is_mmio_pfn(pfn)) {
+		ret = kvm_x86_ops.pin_page(vcpu, gfn, pfn, level, &spte);
+		if (ret) {
+			if (WARN_ON_ONCE(ret > 0))
+				/*
+				 * pin_page() should return 0 on success
+				 * and non-zero preferably less than zero,
+				 * for failure.  We check for any unanticipated
+				 * positive return values here.
+				 */
+				ret = -EINVAL;
+
+			return ret;
+		}
+	}
+
 	if (host_writable)
 		spte |= SPTE_HOST_WRITEABLE;
 	else
@@ -3086,6 +3102,9 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 
 	set_spte_ret = set_spte(vcpu, sptep, pte_access, level, gfn, pfn,
 				speculative, true, host_writable);
+	if (set_spte_ret < 0)
+		return set_spte_ret;
+
 	if (set_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) {
 		if (write_fault)
 			ret = RET_PF_EMULATE;
@@ -3134,7 +3153,7 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
 	struct page *pages[PTE_PREFETCH_NUM];
 	struct kvm_memory_slot *slot;
 	unsigned int access = sp->role.access;
-	int i, ret;
+	int i, ret, error_ret = 0;
 	gfn_t gfn;
 
 	gfn = kvm_mmu_page_get_gfn(sp, start - sp->spt);
@@ -3147,12 +3166,15 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
 		return -1;
 
 	for (i = 0; i < ret; i++, gfn++, start++) {
-		mmu_set_spte(vcpu, start, access, 0, sp->role.level, gfn,
-			     page_to_pfn(pages[i]), true, true);
+		ret = mmu_set_spte(vcpu, start, access, 0, sp->role.level, gfn,
+				   page_to_pfn(pages[i]), true, true);
+		if (ret < 0 && error_ret == 0) /* only track 1st fail */
+			error_ret = ret;
 		put_page(pages[i]);
 	}
 
-	return 0;
+	/* If there was an error for any gfn, return non-0. */
+	return error_ret;
 }
 
 static void __direct_pte_prefetch(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 0172a949f6a7..a777bb43dfa0 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -532,6 +532,7 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 	unsigned pte_access;
 	gfn_t gfn;
 	kvm_pfn_t pfn;
+	int set_spte_ret;
 
 	if (FNAME(prefetch_invalid_gpte)(vcpu, sp, spte, gpte))
 		return false;
@@ -550,11 +551,12 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 	 * we call mmu_set_spte() with host_writable = true because
 	 * pte_prefetch_gfn_to_pfn always gets a writable pfn.
 	 */
-	mmu_set_spte(vcpu, spte, pte_access, 0, PG_LEVEL_4K, gfn, pfn,
-		     true, true);
+	set_spte_ret = mmu_set_spte(vcpu, spte, pte_access, 0,
+				    PG_LEVEL_4K, gfn, pfn, true, true);
 
 	kvm_release_pfn_clean(pfn);
-	return true;
+
+	return set_spte_ret >= 0;
 }
 
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
@@ -1011,7 +1013,8 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	int i, nr_present = 0;
 	bool host_writable;
 	gpa_t first_pte_gpa;
-	int set_spte_ret = 0;
+	int ret;
+	int accum_set_spte_flags = 0;
 
 	/* direct kvm_mmu_page can not be unsync. */
 	BUG_ON(sp->role.direct);
@@ -1064,17 +1067,19 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 			continue;
 		}
 
-		nr_present++;
-
 		host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE;
 
-		set_spte_ret |= set_spte(vcpu, &sp->spt[i],
-					 pte_access, PG_LEVEL_4K,
-					 gfn, spte_to_pfn(sp->spt[i]),
-					 true, false, host_writable);
+		ret = set_spte(vcpu, &sp->spt[i], pte_access,
+			       PG_LEVEL_4K, gfn,
+			       spte_to_pfn(sp->spt[i]), true, false,
+			       host_writable);
+		if (ret >= 0) {
+			nr_present++;
+			accum_set_spte_flags |= ret;
+		}
 	}
 
-	if (set_spte_ret & SET_SPTE_NEED_REMOTE_TLB_FLUSH)
+	if (accum_set_spte_flags & SET_SPTE_NEED_REMOTE_TLB_FLUSH)
 		kvm_flush_remote_tlbs(vcpu->kvm);
 
 	return nr_present;
-- 
2.17.1

[Patch v2 2/4] KVM:SVM: Implement pin_page support

[eric van tassell]

Improve SEV guest startup time from O(n) to a constant by deferring
guest page pinning until the pages are used to satisfy nested page faults.

Implement the code to do the pinning (sev_get_page) and the notifier
sev_pin_page().

Track the pinned pages with xarray so they can be released during guest
termination.

Co-developed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: eric van tassell <Eric.VanTassell@amd.com>
---
 arch/x86/kvm/svm/sev.c | 68 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kvm/svm/svm.c |  2 ++
 arch/x86/kvm/svm/svm.h |  3 ++
 3 files changed, 73 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index f7f1f4ecf08e..8d56d1afb33e 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -184,6 +184,8 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	sev->asid = asid;
 	INIT_LIST_HEAD(&sev->regions_list);
 
+	xa_init(&sev->pages_xarray);
+
 	return 0;
 
 e_free:
@@ -415,6 +417,43 @@ static unsigned long get_num_contig_pages(unsigned long idx,
 	return pages;
 }
 
+static int sev_get_page(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn)
+{
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+	struct xarray *xa = &sev->pages_xarray;
+	struct page *page = pfn_to_page(pfn);
+	int ret;
+
+	/* store page at index = gfn */
+	ret = xa_insert(xa, gfn, page, GFP_ATOMIC);
+	if (ret == -EBUSY) {
+		/*
+		 * If xa_insert returned -EBUSY, the  gfn was already associated
+		 * with a struct page *.
+		 */
+		struct page *cur_page;
+
+		cur_page = xa_load(xa, gfn);
+		/* If cur_page == page, no change is needed, so return 0 */
+		if (cur_page == page)
+			return 0;
+
+		/* Release the page that was stored at index = gfn */
+		put_page(cur_page);
+
+		/* Return result of attempting to store page at index = gfn */
+		ret = xa_err(xa_store(xa, gfn, page, GFP_ATOMIC));
+		WARN_ON(ret != 0);
+	}
+
+	if (ret)
+		return ret;
+
+	get_page(page);
+
+	return 0;
+}
+
 static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
 	unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
@@ -1085,6 +1124,8 @@ void sev_vm_destroy(struct kvm *kvm)
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
 	struct list_head *head = &sev->regions_list;
 	struct list_head *pos, *q;
+	XA_STATE(xas, &sev->pages_xarray, 0);
+	struct page *xa_page;
 
 	if (!sev_guest(kvm))
 		return;
@@ -1109,6 +1150,12 @@ void sev_vm_destroy(struct kvm *kvm)
 		}
 	}
 
+	/* Release each pinned page that SEV tracked in sev->pages_xarray. */
+	xas_for_each(&xas, xa_page, ULONG_MAX) {
+		put_page(xa_page);
+	}
+	xa_destroy(&sev->pages_xarray);
+
 	mutex_unlock(&kvm->lock);
 
 	sev_unbind_asid(kvm, sev->handle);
@@ -1193,3 +1240,24 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu)
 	svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
 	vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
 }
+
+int sev_pin_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn,
+		 int level, u64 *spte)
+{
+	int rc;
+
+	if (!sev_guest(vcpu->kvm))
+		return 0;
+
+	rc = sev_get_page(vcpu->kvm, gfn, pfn);
+	if (rc)
+		return rc;
+
+	/*
+	 * Flush any cached lines of the page being added since "ownership" of
+	 * it will be transferred from the host to an encrypted guest.
+	 */
+	clflush_cache_range(__va(pfn << PAGE_SHIFT), page_level_size(level));
+
+	return 0;
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 535ad311ad02..adb308631416 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4130,6 +4130,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.need_emulation_on_page_fault = svm_need_emulation_on_page_fault,
 
 	.apic_init_signal_blocked = svm_apic_init_signal_blocked,
+
+	.pin_page = sev_pin_page,
 };
 
 static struct kvm_x86_init_ops svm_init_ops __initdata = {
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 121b198b51e9..278c46bc52aa 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -65,6 +65,7 @@ struct kvm_sev_info {
 	int fd;			/* SEV device fd */
 	unsigned long pages_locked; /* Number of pages locked */
 	struct list_head regions_list;  /* List of registered regions */
+	struct xarray pages_xarray; /* List of PFN locked */
 };
 
 struct kvm_svm {
@@ -488,5 +489,7 @@ int svm_unregister_enc_region(struct kvm *kvm,
 void pre_sev_run(struct vcpu_svm *svm, int cpu);
 int __init sev_hardware_setup(void);
 void sev_hardware_teardown(void);
+int sev_pin_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn,
+		 int level, u64 *spte);
 
 #endif
-- 
2.17.1

[Patch v2 3/4] KVM:SVM: Pin sev_launch_update_data() pages via sev_get_page()

[eric van tassell]

Add 2 small infrastructure functions here which to enable pinning the SEV
guest pages used for sev_launch_update_data() using sev_get_page().

Pin the memory for the data being passed to launch_update_data() because it
gets encrypted before the guest is first run and must not be moved which
would corrupt it.

Co-developed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: eric van tassell <Eric.VanTassell@amd.com>
---
 arch/x86/kvm/svm/sev.c | 57 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d56d1afb33e..4a0157254fef 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -454,6 +454,37 @@ static int sev_get_page(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn)
 	return 0;
 }
 
+static struct kvm_memory_slot *hva_to_memslot(struct kvm *kvm,
+					      unsigned long hva)
+{
+	struct kvm_memslots *slots = kvm_memslots(kvm);
+	struct kvm_memory_slot *memslot;
+
+	kvm_for_each_memslot(memslot, slots) {
+		if (hva >= memslot->userspace_addr &&
+		    hva < memslot->userspace_addr +
+			      (memslot->npages << PAGE_SHIFT))
+			return memslot;
+	}
+
+	return NULL;
+}
+
+static bool hva_to_gfn(struct kvm *kvm, unsigned long hva, gfn_t *gfn)
+{
+	struct kvm_memory_slot *memslot;
+	gpa_t gpa_offset;
+
+	memslot = hva_to_memslot(kvm, hva);
+	if (!memslot)
+		return false;
+
+	gpa_offset = hva - memslot->userspace_addr;
+	*gfn = ((memslot->base_gfn << PAGE_SHIFT) + gpa_offset) >> PAGE_SHIFT;
+
+	return true;
+}
+
 static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
 	unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
@@ -462,6 +493,7 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	struct sev_data_launch_update_data *data;
 	struct page **inpages;
 	int ret;
+	int srcu_idx;
 
 	if (!sev_guest(kvm))
 		return -ENOTTY;
@@ -484,6 +516,31 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 		goto e_free;
 	}
 
+	/*
+	 * Increment the page ref count so that the pages do not get migrated or
+	 * moved after we are done from the LAUNCH_UPDATE_DATA.
+	 */
+
+	/* ensure hva_to_gfn translations remain valid */
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+
+	for (i = 0; i < npages; i++) {
+		gfn_t gfn;
+
+		if (!hva_to_gfn(kvm, (vaddr + (i * PAGE_SIZE)) & PAGE_MASK, &gfn)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		ret = sev_get_page(kvm, gfn, page_to_pfn(inpages[i]));
+		if (ret)
+			break;
+	}
+
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+	if (ret)
+		goto e_unpin;
+
 	/*
 	 * The LAUNCH_UPDATE command will perform in-place encryption of the
 	 * memory content (i.e it will write the same memory region with C=1).
-- 
2.17.1

[Patch v2 4/4] KVM:SVM: Remove struct enc_region and associated pinned page tracking.

[eric van tassell]

Remove the enc_region structure definition and the code which maintained
it, as they are no longer needed in view of the xarray support we added in
the previous patch.

Leave svm_register_enc_region() and svm_unregister_enc_region() as stubs
since the ioctl is used by qemu and qemu will crash if they do not
return 0.

Co-developed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: eric van tassell <Eric.VanTassell@amd.com>
---
 arch/x86/kvm/svm/sev.c | 117 +----------------------------------------
 arch/x86/kvm/svm/svm.h |   1 -
 2 files changed, 1 insertion(+), 117 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4a0157254fef..635e15f01edb 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -27,14 +27,6 @@ static unsigned long *sev_asid_bitmap;
 static unsigned long *sev_reclaim_asid_bitmap;
 #define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
 
-struct enc_region {
-	struct list_head list;
-	unsigned long npages;
-	struct page **pages;
-	unsigned long uaddr;
-	unsigned long size;
-};
-
 static int sev_flush_asids(void)
 {
 	int ret, error = 0;
@@ -182,7 +174,6 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 	sev->active = true;
 	sev->asid = asid;
-	INIT_LIST_HEAD(&sev->regions_list);
 
 	xa_init(&sev->pages_xarray);
 
@@ -1074,113 +1065,18 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 int svm_register_enc_region(struct kvm *kvm,
 			    struct kvm_enc_region *range)
 {
-	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	struct enc_region *region;
-	int ret = 0;
-
-	if (!sev_guest(kvm))
-		return -ENOTTY;
-
-	if (range->addr > ULONG_MAX || range->size > ULONG_MAX)
-		return -EINVAL;
-
-	region = kzalloc(sizeof(*region), GFP_KERNEL_ACCOUNT);
-	if (!region)
-		return -ENOMEM;
-
-	region->pages = sev_pin_memory(kvm, range->addr, range->size, &region->npages, 1);
-	if (IS_ERR(region->pages)) {
-		ret = PTR_ERR(region->pages);
-		goto e_free;
-	}
-
-	/*
-	 * The guest may change the memory encryption attribute from C=0 -> C=1
-	 * or vice versa for this memory range. Lets make sure caches are
-	 * flushed to ensure that guest data gets written into memory with
-	 * correct C-bit.
-	 */
-	sev_clflush_pages(region->pages, region->npages);
-
-	region->uaddr = range->addr;
-	region->size = range->size;
-
-	mutex_lock(&kvm->lock);
-	list_add_tail(&region->list, &sev->regions_list);
-	mutex_unlock(&kvm->lock);
-
-	return ret;
-
-e_free:
-	kfree(region);
-	return ret;
-}
-
-static struct enc_region *
-find_enc_region(struct kvm *kvm, struct kvm_enc_region *range)
-{
-	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	struct list_head *head = &sev->regions_list;
-	struct enc_region *i;
-
-	list_for_each_entry(i, head, list) {
-		if (i->uaddr == range->addr &&
-		    i->size == range->size)
-			return i;
-	}
-
-	return NULL;
-}
-
-static void __unregister_enc_region_locked(struct kvm *kvm,
-					   struct enc_region *region)
-{
-	sev_unpin_memory(kvm, region->pages, region->npages);
-	list_del(&region->list);
-	kfree(region);
+	return 0;
 }
 
 int svm_unregister_enc_region(struct kvm *kvm,
 			      struct kvm_enc_region *range)
 {
-	struct enc_region *region;
-	int ret;
-
-	mutex_lock(&kvm->lock);
-
-	if (!sev_guest(kvm)) {
-		ret = -ENOTTY;
-		goto failed;
-	}
-
-	region = find_enc_region(kvm, range);
-	if (!region) {
-		ret = -EINVAL;
-		goto failed;
-	}
-
-	/*
-	 * Ensure that all guest tagged cache entries are flushed before
-	 * releasing the pages back to the system for use. CLFLUSH will
-	 * not do this, so issue a WBINVD.
-	 */
-	wbinvd_on_all_cpus();
-
-	__unregister_enc_region_locked(kvm, region);
-
-	mutex_unlock(&kvm->lock);
 	return 0;
-
-failed:
-	mutex_unlock(&kvm->lock);
-	return ret;
 }
 
 void sev_vm_destroy(struct kvm *kvm)
 {
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-	struct list_head *head = &sev->regions_list;
-	struct list_head *pos, *q;
 	XA_STATE(xas, &sev->pages_xarray, 0);
 	struct page *xa_page;
 
@@ -1196,17 +1092,6 @@ void sev_vm_destroy(struct kvm *kvm)
 	 */
 	wbinvd_on_all_cpus();
 
-	/*
-	 * if userspace was terminated before unregistering the memory regions
-	 * then lets unpin all the registered memory.
-	 */
-	if (!list_empty(head)) {
-		list_for_each_safe(pos, q, head) {
-			__unregister_enc_region_locked(kvm,
-				list_entry(pos, struct enc_region, list));
-		}
-	}
-
 	/* Release each pinned page that SEV tracked in sev->pages_xarray. */
 	xas_for_each(&xas, xa_page, ULONG_MAX) {
 		put_page(xa_page);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 278c46bc52aa..98d3d7b299cb 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -64,7 +64,6 @@ struct kvm_sev_info {
 	unsigned int handle;	/* SEV firmware handle */
 	int fd;			/* SEV device fd */
 	unsigned long pages_locked; /* Number of pages locked */
-	struct list_head regions_list;  /* List of registered regions */
 	struct xarray pages_xarray; /* List of PFN locked */
 };
 
-- 
2.17.1