arch/s390/kernel/uv.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Common Ultravisor functions and initialization
  *
  * Copyright IBM Corp. 2019, 2020
  */
 #define KMSG_COMPONENT "prot_virt"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/sizes.h>
 #include <linux/bitmap.h>
 #include <linux/memblock.h>
 #include <linux/pagemap.h>
 #include <linux/swap.h>
 #include <asm/facility.h>
 #include <asm/sections.h>
 #include <asm/uv.h>

 /* the bootdata_preserved fields come from ones in arch/s390/boot/uv.c */
 #ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 int __bootdata_preserved(prot_virt_guest);
 #endif

 struct uv_info __bootdata_preserved(uv_info);

 #if IS_ENABLED(CONFIG_KVM)
 int __bootdata_preserved(prot_virt_host);
 EXPORT_SYMBOL(prot_virt_host);
 EXPORT_SYMBOL(uv_info);

 static int __init uv_init(unsigned long stor_base, unsigned long stor_len)
 {
 	struct uv_cb_init uvcb = {
 		.header.cmd = UVC_CMD_INIT_UV,
 		.header.len = sizeof(uvcb),
 		.stor_origin = stor_base,
 		.stor_len = stor_len,
 	};

 	if (uv_call(0, (uint64_t)&uvcb)) {
 		pr_err("Ultravisor init failed with rc: 0x%x rrc: 0%x\n",
 		       uvcb.header.rc, uvcb.header.rrc);
 		return -1;
 	}
 	return 0;
 }

 void __init setup_uv(void)
 {
 	unsigned long uv_stor_base;

 	/*
 	 * keep these conditions in line with kasan init code has_uv_sec_stor_limit()
 	 */
 	if (!is_prot_virt_host())
 		return;

 	if (is_prot_virt_guest()) {
 		prot_virt_host = 0;
 		pr_warn("Protected virtualization not available in protected guests.");
 		return;
 	}

 	if (!test_facility(158)) {
 		prot_virt_host = 0;
 		pr_warn("Protected virtualization not supported by the hardware.");
 		return;
 	}

 	uv_stor_base = (unsigned long)memblock_alloc_try_nid(
 		uv_info.uv_base_stor_len, SZ_1M, SZ_2G,
 		MEMBLOCK_ALLOC_ACCESSIBLE, NUMA_NO_NODE);
 	if (!uv_stor_base) {
 		pr_warn("Failed to reserve %lu bytes for ultravisor base storage\n",
 			uv_info.uv_base_stor_len);
 		goto fail;
 	}

 	if (uv_init(uv_stor_base, uv_info.uv_base_stor_len)) {
 		memblock_free(uv_stor_base, uv_info.uv_base_stor_len);
 		goto fail;
 	}

 	pr_info("Reserving %luMB as ultravisor base storage\n",
 		uv_info.uv_base_stor_len >> 20);
 	return;
 fail:
 	pr_info("Disabling support for protected virtualization");
 	prot_virt_host = 0;
 }

 void adjust_to_uv_max(unsigned long *vmax)
 {
 	if (uv_info.max_sec_stor_addr)
 		*vmax = min_t(unsigned long, *vmax, uv_info.max_sec_stor_addr);
 }

 /*
  * Requests the Ultravisor to pin the page in the shared state. This will
  * cause an intercept when the guest attempts to unshare the pinned page.
  */
 static int uv_pin_shared(unsigned long paddr)
 {
 	struct uv_cb_cfs uvcb = {
 		.header.cmd = UVC_CMD_PIN_PAGE_SHARED,
 		.header.len = sizeof(uvcb),
 		.paddr = paddr,
 	};

 	if (uv_call(0, (u64)&uvcb))
 		return -EINVAL;
 	return 0;
 }

 /*
  * Requests the Ultravisor to destroy a guest page and make it
  * accessible to the host. The destroy clears the page instead of
  * exporting.
  *
  * @paddr: Absolute host address of page to be destroyed
  */
 int uv_destroy_page(unsigned long paddr)
 {
 	struct uv_cb_cfs uvcb = {
 		.header.cmd = UVC_CMD_DESTR_SEC_STOR,
 		.header.len = sizeof(uvcb),
 		.paddr = paddr
 	};

 	if (uv_call(0, (u64)&uvcb)) {
 		/*
 		 * Older firmware uses 107/d as an indication of a non secure
 		 * page. Let us emulate the newer variant (no-op).
 		 */
 		if (uvcb.header.rc == 0x107 && uvcb.header.rrc == 0xd)
 			return 0;
 		return -EINVAL;
 	}
 	return 0;
 }

 /*
  * Requests the Ultravisor to encrypt a guest page and make it
  * accessible to the host for paging (export).
  *
  * @paddr: Absolute host address of page to be exported
  */
 int uv_convert_from_secure(unsigned long paddr)
 {
 	struct uv_cb_cfs uvcb = {
 		.header.cmd = UVC_CMD_CONV_FROM_SEC_STOR,
 		.header.len = sizeof(uvcb),
 		.paddr = paddr
 	};

 	if (uv_call(0, (u64)&uvcb))
 		return -EINVAL;
 	return 0;
 }

 /*
  * Calculate the expected ref_count for a page that would otherwise have no
  * further pins. This was cribbed from similar functions in other places in
  * the kernel, but with some slight modifications. We know that a secure
  * page can not be a huge page for example.
  */
 static int expected_page_refs(struct page *page)
 {
 	int res;

 	res = page_mapcount(page);
 	if (PageSwapCache(page)) {
 		res++;
 	} else if (page_mapping(page)) {
 		res++;
 		if (page_has_private(page))
 			res++;
 	}
 	return res;
 }

 static int make_secure_pte(pte_t *ptep, unsigned long addr,
 			   struct page *exp_page, struct uv_cb_header *uvcb)
 {
 	pte_t entry = READ_ONCE(*ptep);
 	struct page *page;
 	int expected, rc = 0;

 	if (!pte_present(entry))
 		return -ENXIO;
 	if (pte_val(entry) & _PAGE_INVALID)
 		return -ENXIO;

 	page = pte_page(entry);
 	if (page != exp_page)
 		return -ENXIO;
 	if (PageWriteback(page))
 		return -EAGAIN;
 	expected = expected_page_refs(page);
 	if (!page_ref_freeze(page, expected))
 		return -EBUSY;
 	set_bit(PG_arch_1, &page->flags);
 	rc = uv_call(0, (u64)uvcb);
 	page_ref_unfreeze(page, expected);
 	/* Return -ENXIO if the page was not mapped, -EINVAL otherwise */
 	if (rc)
 		rc = uvcb->rc == 0x10a ? -ENXIO : -EINVAL;
 	return rc;
 }

 /*
  * Requests the Ultravisor to make a page accessible to a guest.
  * If it's brought in the first time, it will be cleared. If
  * it has been exported before, it will be decrypted and integrity
  * checked.
  */
 int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb)
 {
 	struct vm_area_struct *vma;
 	bool local_drain = false;
 	spinlock_t *ptelock;
 	unsigned long uaddr;
 	struct page *page;
 	pte_t *ptep;
 	int rc;

 again:
 	rc = -EFAULT;
 	mmap_read_lock(gmap->mm);

 	uaddr = __gmap_translate(gmap, gaddr);
 	if (IS_ERR_VALUE(uaddr))
 		goto out;
 	vma = find_vma(gmap->mm, uaddr);
 	if (!vma)
 		goto out;
 	/*
 	 * Secure pages cannot be huge and userspace should not combine both.
 	 * In case userspace does it anyway this will result in an -EFAULT for
 	 * the unpack. The guest is thus never reaching secure mode. If
 	 * userspace is playing dirty tricky with mapping huge pages later
 	 * on this will result in a segmentation fault.
 	 */
 	if (is_vm_hugetlb_page(vma))
 		goto out;

 	rc = -ENXIO;
 	page = follow_page(vma, uaddr, FOLL_WRITE);
 	if (IS_ERR_OR_NULL(page))
 		goto out;

 	lock_page(page);
 	ptep = get_locked_pte(gmap->mm, uaddr, &ptelock);
 	rc = make_secure_pte(ptep, uaddr, page, uvcb);
 	pte_unmap_unlock(ptep, ptelock);
 	unlock_page(page);
 out:
 	mmap_read_unlock(gmap->mm);

 	if (rc == -EAGAIN) {
 		wait_on_page_writeback(page);
 	} else if (rc == -EBUSY) {
 		/*
 		 * If we have tried a local drain and the page refcount
 		 * still does not match our expected safe value, try with a
 		 * system wide drain. This is needed if the pagevecs holding
 		 * the page are on a different CPU.
 		 */
 		if (local_drain) {
 			lru_add_drain_all();
 			/* We give up here, and let the caller try again */
 			return -EAGAIN;
 		}
 		/*
 		 * We are here if the page refcount does not match the
 		 * expected safe value. The main culprits are usually
 		 * pagevecs. With lru_add_drain() we drain the pagevecs
 		 * on the local CPU so that hopefully the refcount will
 		 * reach the expected safe value.
 		 */
 		lru_add_drain();
 		local_drain = true;
 		/* And now we try again immediately after draining */
 		goto again;
 	} else if (rc == -ENXIO) {
 		if (gmap_fault(gmap, gaddr, FAULT_FLAG_WRITE))
 			return -EFAULT;
 		return -EAGAIN;
 	}
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_make_secure);

 int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr)
 {
 	struct uv_cb_cts uvcb = {
 		.header.cmd = UVC_CMD_CONV_TO_SEC_STOR,
 		.header.len = sizeof(uvcb),
 		.guest_handle = gmap->guest_handle,
 		.gaddr = gaddr,
 	};

 	return gmap_make_secure(gmap, gaddr, &uvcb);
 }
 EXPORT_SYMBOL_GPL(gmap_convert_to_secure);

 /*
  * To be called with the page locked or with an extra reference! This will
  * prevent gmap_make_secure from touching the page concurrently. Having 2
  * parallel make_page_accessible is fine, as the UV calls will become a
  * no-op if the page is already exported.
  */
 int arch_make_page_accessible(struct page *page)
 {
 	int rc = 0;

 	/* Hugepage cannot be protected, so nothing to do */
 	if (PageHuge(page))
 		return 0;

 	/*
 	 * PG_arch_1 is used in 3 places:
 	 * 1. for kernel page tables during early boot
 	 * 2. for storage keys of huge pages and KVM
 	 * 3. As an indication that this page might be secure. This can
 	 *    overindicate, e.g. we set the bit before calling
 	 *    convert_to_secure.
 	 * As secure pages are never huge, all 3 variants can co-exists.
 	 */
 	if (!test_bit(PG_arch_1, &page->flags))
 		return 0;

 	rc = uv_pin_shared(page_to_phys(page));
 	if (!rc) {
 		clear_bit(PG_arch_1, &page->flags);
 		return 0;
 	}

 	rc = uv_convert_from_secure(page_to_phys(page));
 	if (!rc) {
 		clear_bit(PG_arch_1, &page->flags);
 		return 0;
 	}

 	return rc;
 }
 EXPORT_SYMBOL_GPL(arch_make_page_accessible);

 #endif

 #if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || IS_ENABLED(CONFIG_KVM)
 static ssize_t uv_query_facilities(struct kobject *kobj,
 				   struct kobj_attribute *attr, char *page)
 {
 	return scnprintf(page, PAGE_SIZE, "%lx\n%lx\n%lx\n%lx\n",
 			uv_info.inst_calls_list[0],
 			uv_info.inst_calls_list[1],
 			uv_info.inst_calls_list[2],
 			uv_info.inst_calls_list[3]);
 }

 static struct kobj_attribute uv_query_facilities_attr =
 	__ATTR(facilities, 0444, uv_query_facilities, NULL);

 static ssize_t uv_query_feature_indications(struct kobject *kobj,
 					    struct kobj_attribute *attr, char *buf)
 {
 	return sysfs_emit(buf, "%lx\n", uv_info.uv_feature_indications);
 }

 static struct kobj_attribute uv_query_feature_indications_attr =
 	__ATTR(feature_indications, 0444, uv_query_feature_indications, NULL);

 static ssize_t uv_query_max_guest_cpus(struct kobject *kobj,
 				       struct kobj_attribute *attr, char *page)
 {
 	return scnprintf(page, PAGE_SIZE, "%d\n",
 			uv_info.max_guest_cpu_id + 1);
 }

 static struct kobj_attribute uv_query_max_guest_cpus_attr =
 	__ATTR(max_cpus, 0444, uv_query_max_guest_cpus, NULL);

 static ssize_t uv_query_max_guest_vms(struct kobject *kobj,
 				      struct kobj_attribute *attr, char *page)
 {
 	return scnprintf(page, PAGE_SIZE, "%d\n",
 			uv_info.max_num_sec_conf);
 }

 static struct kobj_attribute uv_query_max_guest_vms_attr =
 	__ATTR(max_guests, 0444, uv_query_max_guest_vms, NULL);

 static ssize_t uv_query_max_guest_addr(struct kobject *kobj,
 				       struct kobj_attribute *attr, char *page)
 {
 	return scnprintf(page, PAGE_SIZE, "%lx\n",
 			uv_info.max_sec_stor_addr);
 }

 static struct kobj_attribute uv_query_max_guest_addr_attr =
 	__ATTR(max_address, 0444, uv_query_max_guest_addr, NULL);

 static struct attribute *uv_query_attrs[] = {
 	&uv_query_facilities_attr.attr,
 	&uv_query_feature_indications_attr.attr,
 	&uv_query_max_guest_cpus_attr.attr,
 	&uv_query_max_guest_vms_attr.attr,
 	&uv_query_max_guest_addr_attr.attr,
 	NULL,
 };

 static struct attribute_group uv_query_attr_group = {
 	.attrs = uv_query_attrs,
 };

 static struct kset *uv_query_kset;
 static struct kobject *uv_kobj;

 static int __init uv_info_init(void)
 {
 	int rc = -ENOMEM;

 	if (!test_facility(158))
 		return 0;

 	uv_kobj = kobject_create_and_add("uv", firmware_kobj);
 	if (!uv_kobj)
 		return -ENOMEM;

 	uv_query_kset = kset_create_and_add("query", NULL, uv_kobj);
 	if (!uv_query_kset)
 		goto out_kobj;

 	rc = sysfs_create_group(&uv_query_kset->kobj, &uv_query_attr_group);
 	if (!rc)
 		return 0;

 	kset_unregister(uv_query_kset);
 out_kobj:
 	kobject_del(uv_kobj);
 	kobject_put(uv_kobj);
 	return rc;
 }
 device_initcall(uv_info_init);
 #endif
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Common Ultravisor functions and initialization
	*
	* Copyright IBM Corp. 2019, 2020
	*/
	#define KMSG_COMPONENT "prot_virt"
	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/sizes.h>
	#include <linux/bitmap.h>
	#include <linux/memblock.h>
	#include <linux/pagemap.h>
	#include <linux/swap.h>
	#include <asm/facility.h>
	#include <asm/sections.h>
	#include <asm/uv.h>

	/* the bootdata_preserved fields come from ones in arch/s390/boot/uv.c */
	#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
	int __bootdata_preserved(prot_virt_guest);
	#endif

	struct uv_info __bootdata_preserved(uv_info);

	#if IS_ENABLED(CONFIG_KVM)
	int __bootdata_preserved(prot_virt_host);
	EXPORT_SYMBOL(prot_virt_host);
	EXPORT_SYMBOL(uv_info);

	static int __init uv_init(unsigned long stor_base, unsigned long stor_len)
	{
	struct uv_cb_init uvcb = {
	.header.cmd = UVC_CMD_INIT_UV,
	.header.len = sizeof(uvcb),
	.stor_origin = stor_base,
	.stor_len = stor_len,
	};

	if (uv_call(0, (uint64_t)&uvcb)) {
	pr_err("Ultravisor init failed with rc: 0x%x rrc: 0%x\n",
	uvcb.header.rc, uvcb.header.rrc);
	return -1;
	}
	return 0;
	}

	void __init setup_uv(void)
	{
	unsigned long uv_stor_base;

	/*
	* keep these conditions in line with kasan init code has_uv_sec_stor_limit()
	*/
	if (!is_prot_virt_host())
	return;

	if (is_prot_virt_guest()) {
	prot_virt_host = 0;
	pr_warn("Protected virtualization not available in protected guests.");
	return;
	}

	if (!test_facility(158)) {
	prot_virt_host = 0;
	pr_warn("Protected virtualization not supported by the hardware.");
	return;
	}

	uv_stor_base = (unsigned long)memblock_alloc_try_nid(
	uv_info.uv_base_stor_len, SZ_1M, SZ_2G,
	MEMBLOCK_ALLOC_ACCESSIBLE, NUMA_NO_NODE);
	if (!uv_stor_base) {
	pr_warn("Failed to reserve %lu bytes for ultravisor base storage\n",
	uv_info.uv_base_stor_len);
	goto fail;
	}

	if (uv_init(uv_stor_base, uv_info.uv_base_stor_len)) {
	memblock_free(uv_stor_base, uv_info.uv_base_stor_len);
	goto fail;
	}

	pr_info("Reserving %luMB as ultravisor base storage\n",
	uv_info.uv_base_stor_len >> 20);
	return;
	fail:
	pr_info("Disabling support for protected virtualization");
	prot_virt_host = 0;
	}

	void adjust_to_uv_max(unsigned long *vmax)
	{
	if (uv_info.max_sec_stor_addr)
	vmax = min_t(unsigned long, vmax, uv_info.max_sec_stor_addr);
	}

	/*
	* Requests the Ultravisor to pin the page in the shared state. This will
	* cause an intercept when the guest attempts to unshare the pinned page.
	*/
	static int uv_pin_shared(unsigned long paddr)
	{
	struct uv_cb_cfs uvcb = {
	.header.cmd = UVC_CMD_PIN_PAGE_SHARED,
	.header.len = sizeof(uvcb),
	.paddr = paddr,
	};

	if (uv_call(0, (u64)&uvcb))
	return -EINVAL;
	return 0;
	}

	/*
	* Requests the Ultravisor to destroy a guest page and make it
	* accessible to the host. The destroy clears the page instead of
	* exporting.
	*
	* @paddr: Absolute host address of page to be destroyed
	*/
	int uv_destroy_page(unsigned long paddr)
	{
	struct uv_cb_cfs uvcb = {
	.header.cmd = UVC_CMD_DESTR_SEC_STOR,
	.header.len = sizeof(uvcb),
	.paddr = paddr
	};

	if (uv_call(0, (u64)&uvcb)) {
	/*
	* Older firmware uses 107/d as an indication of a non secure
	* page. Let us emulate the newer variant (no-op).
	*/
	if (uvcb.header.rc == 0x107 && uvcb.header.rrc == 0xd)
	return 0;
	return -EINVAL;
	}
	return 0;
	}

	/*
	* Requests the Ultravisor to encrypt a guest page and make it
	* accessible to the host for paging (export).
	*
	* @paddr: Absolute host address of page to be exported
	*/
	int uv_convert_from_secure(unsigned long paddr)
	{
	struct uv_cb_cfs uvcb = {
	.header.cmd = UVC_CMD_CONV_FROM_SEC_STOR,
	.header.len = sizeof(uvcb),
	.paddr = paddr
	};

	if (uv_call(0, (u64)&uvcb))
	return -EINVAL;
	return 0;
	}

	/*
	* Calculate the expected ref_count for a page that would otherwise have no
	* further pins. This was cribbed from similar functions in other places in
	* the kernel, but with some slight modifications. We know that a secure
	* page can not be a huge page for example.
	*/
	static int expected_page_refs(struct page *page)
	{
	int res;

	res = page_mapcount(page);
	if (PageSwapCache(page)) {
	res++;
	} else if (page_mapping(page)) {
	res++;
	if (page_has_private(page))
	res++;
	}
	return res;
	}

	static int make_secure_pte(pte_t *ptep, unsigned long addr,
	struct page exp_page, struct uv_cb_header uvcb)
	{
	pte_t entry = READ_ONCE(*ptep);
	struct page *page;
	int expected, rc = 0;

	if (!pte_present(entry))
	return -ENXIO;
	if (pte_val(entry) & _PAGE_INVALID)
	return -ENXIO;

	page = pte_page(entry);
	if (page != exp_page)
	return -ENXIO;
	if (PageWriteback(page))
	return -EAGAIN;
	expected = expected_page_refs(page);
	if (!page_ref_freeze(page, expected))
	return -EBUSY;
	set_bit(PG_arch_1, &page->flags);
	rc = uv_call(0, (u64)uvcb);
	page_ref_unfreeze(page, expected);
	/* Return -ENXIO if the page was not mapped, -EINVAL otherwise */
	if (rc)
	rc = uvcb->rc == 0x10a ? -ENXIO : -EINVAL;
	return rc;
	}

	/*
	* Requests the Ultravisor to make a page accessible to a guest.
	* If it's brought in the first time, it will be cleared. If
	* it has been exported before, it will be decrypted and integrity
	* checked.
	*/
	int gmap_make_secure(struct gmap gmap, unsigned long gaddr, void uvcb)
	{
	struct vm_area_struct *vma;
	bool local_drain = false;
	spinlock_t *ptelock;
	unsigned long uaddr;
	struct page *page;
	pte_t *ptep;
	int rc;

	again:
	rc = -EFAULT;
	mmap_read_lock(gmap->mm);

	uaddr = __gmap_translate(gmap, gaddr);
	if (IS_ERR_VALUE(uaddr))
	goto out;
	vma = find_vma(gmap->mm, uaddr);
	if (!vma)
	goto out;
	/*
	* Secure pages cannot be huge and userspace should not combine both.
	* In case userspace does it anyway this will result in an -EFAULT for
	* the unpack. The guest is thus never reaching secure mode. If
	* userspace is playing dirty tricky with mapping huge pages later
	* on this will result in a segmentation fault.
	*/
	if (is_vm_hugetlb_page(vma))
	goto out;

	rc = -ENXIO;
	page = follow_page(vma, uaddr, FOLL_WRITE);
	if (IS_ERR_OR_NULL(page))
	goto out;

	lock_page(page);
	ptep = get_locked_pte(gmap->mm, uaddr, &ptelock);
	rc = make_secure_pte(ptep, uaddr, page, uvcb);
	pte_unmap_unlock(ptep, ptelock);
	unlock_page(page);
	out:
	mmap_read_unlock(gmap->mm);

	if (rc == -EAGAIN) {
	wait_on_page_writeback(page);
	} else if (rc == -EBUSY) {
	/*
	* If we have tried a local drain and the page refcount
	* still does not match our expected safe value, try with a
	* system wide drain. This is needed if the pagevecs holding
	* the page are on a different CPU.
	*/
	if (local_drain) {
	lru_add_drain_all();
	/* We give up here, and let the caller try again */
	return -EAGAIN;
	}
	/*
	* We are here if the page refcount does not match the
	* expected safe value. The main culprits are usually
	* pagevecs. With lru_add_drain() we drain the pagevecs
	* on the local CPU so that hopefully the refcount will
	* reach the expected safe value.
	*/
	lru_add_drain();
	local_drain = true;
	/* And now we try again immediately after draining */
	goto again;
	} else if (rc == -ENXIO) {
	if (gmap_fault(gmap, gaddr, FAULT_FLAG_WRITE))
	return -EFAULT;
	return -EAGAIN;
	}
	return rc;
	}
	EXPORT_SYMBOL_GPL(gmap_make_secure);

	int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr)
	{
	struct uv_cb_cts uvcb = {
	.header.cmd = UVC_CMD_CONV_TO_SEC_STOR,
	.header.len = sizeof(uvcb),
	.guest_handle = gmap->guest_handle,
	.gaddr = gaddr,
	};

	return gmap_make_secure(gmap, gaddr, &uvcb);
	}
	EXPORT_SYMBOL_GPL(gmap_convert_to_secure);

	/*
	* To be called with the page locked or with an extra reference! This will
	* prevent gmap_make_secure from touching the page concurrently. Having 2
	* parallel make_page_accessible is fine, as the UV calls will become a
	* no-op if the page is already exported.
	*/
	int arch_make_page_accessible(struct page *page)
	{
	int rc = 0;

	/* Hugepage cannot be protected, so nothing to do */
	if (PageHuge(page))
	return 0;

	/*
	* PG_arch_1 is used in 3 places:
	* 1. for kernel page tables during early boot
	* 2. for storage keys of huge pages and KVM
	* 3. As an indication that this page might be secure. This can
	* overindicate, e.g. we set the bit before calling
	* convert_to_secure.
	* As secure pages are never huge, all 3 variants can co-exists.
	*/
	if (!test_bit(PG_arch_1, &page->flags))
	return 0;

	rc = uv_pin_shared(page_to_phys(page));
	if (!rc) {
	clear_bit(PG_arch_1, &page->flags);
	return 0;
	}

	rc = uv_convert_from_secure(page_to_phys(page));
	if (!rc) {
	clear_bit(PG_arch_1, &page->flags);
	return 0;
	}

	return rc;
	}
	EXPORT_SYMBOL_GPL(arch_make_page_accessible);

	#endif

	#if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) \|\| IS_ENABLED(CONFIG_KVM)
	static ssize_t uv_query_facilities(struct kobject *kobj,
	struct kobj_attribute attr, char page)
	{
	return scnprintf(page, PAGE_SIZE, "%lx\n%lx\n%lx\n%lx\n",
	uv_info.inst_calls_list[0],
	uv_info.inst_calls_list[1],
	uv_info.inst_calls_list[2],
	uv_info.inst_calls_list[3]);
	}

	static struct kobj_attribute uv_query_facilities_attr =
	__ATTR(facilities, 0444, uv_query_facilities, NULL);

	static ssize_t uv_query_feature_indications(struct kobject *kobj,
	struct kobj_attribute attr, char buf)
	{
	return sysfs_emit(buf, "%lx\n", uv_info.uv_feature_indications);
	}

	static struct kobj_attribute uv_query_feature_indications_attr =
	__ATTR(feature_indications, 0444, uv_query_feature_indications, NULL);

	static ssize_t uv_query_max_guest_cpus(struct kobject *kobj,
	struct kobj_attribute attr, char page)
	{
	return scnprintf(page, PAGE_SIZE, "%d\n",
	uv_info.max_guest_cpu_id + 1);
	}

	static struct kobj_attribute uv_query_max_guest_cpus_attr =
	__ATTR(max_cpus, 0444, uv_query_max_guest_cpus, NULL);

	static ssize_t uv_query_max_guest_vms(struct kobject *kobj,
	struct kobj_attribute attr, char page)
	{
	return scnprintf(page, PAGE_SIZE, "%d\n",
	uv_info.max_num_sec_conf);
	}

	static struct kobj_attribute uv_query_max_guest_vms_attr =
	__ATTR(max_guests, 0444, uv_query_max_guest_vms, NULL);

	static ssize_t uv_query_max_guest_addr(struct kobject *kobj,
	struct kobj_attribute attr, char page)
	{
	return scnprintf(page, PAGE_SIZE, "%lx\n",
	uv_info.max_sec_stor_addr);
	}

	static struct kobj_attribute uv_query_max_guest_addr_attr =
	__ATTR(max_address, 0444, uv_query_max_guest_addr, NULL);

	static struct attribute *uv_query_attrs[] = {
	&uv_query_facilities_attr.attr,
	&uv_query_feature_indications_attr.attr,
	&uv_query_max_guest_cpus_attr.attr,
	&uv_query_max_guest_vms_attr.attr,
	&uv_query_max_guest_addr_attr.attr,
	NULL,
	};

	static struct attribute_group uv_query_attr_group = {
	.attrs = uv_query_attrs,
	};

	static struct kset *uv_query_kset;
	static struct kobject *uv_kobj;

	static int __init uv_info_init(void)
	{
	int rc = -ENOMEM;

	if (!test_facility(158))
	return 0;

	uv_kobj = kobject_create_and_add("uv", firmware_kobj);
	if (!uv_kobj)
	return -ENOMEM;

	uv_query_kset = kset_create_and_add("query", NULL, uv_kobj);
	if (!uv_query_kset)
	goto out_kobj;

	rc = sysfs_create_group(&uv_query_kset->kobj, &uv_query_attr_group);
	if (!rc)
	return 0;

	kset_unregister(uv_query_kset);
	out_kobj:
	kobject_del(uv_kobj);
	kobject_put(uv_kobj);
	return rc;
	}
	device_initcall(uv_info_init);
	#endif