Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 717 insertions, 0 deletions

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
new file mode 100644
index 0000000000..fc07bc39e6
--- /dev/null
+++ b/arch/s390/kernel/uv.c
@@ -0,0 +1,717 @@
+// 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
+
+/*
+ * uv_info contains both host and guest information but it's currently only
+ * expected to be used within modules if it's the KVM module or for
+ * any PV guest module.
+ *
+ * The kernel itself will write these values once in uv_query_info()
+ * and then make some of them readable via a sysfs interface.
+ */
+struct uv_info __bootdata_preserved(uv_info);
+EXPORT_SYMBOL(uv_info);
+
+#if IS_ENABLED(CONFIG_KVM)
+int __bootdata_preserved(prot_virt_host);
+EXPORT_SYMBOL(prot_virt_host);
+
+static int __init uv_init(phys_addr_t 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)
+{
+	void *uv_stor_base;
+
+	if (!is_prot_virt_host())
+		return;
+
+	uv_stor_base = 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(__pa(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;
+}
+
+/*
+ * 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.
+ */
+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;
+}
+EXPORT_SYMBOL_GPL(uv_pin_shared);
+
+/*
+ * 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
+ */
+static 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;
+}
+
+/*
+ * The caller must already hold a reference to the page
+ */
+int uv_destroy_owned_page(unsigned long paddr)
+{
+	struct page *page = phys_to_page(paddr);
+	int rc;
+
+	get_page(page);
+	rc = uv_destroy_page(paddr);
+	if (!rc)
+		clear_bit(PG_arch_1, &page->flags);
+	put_page(page);
+	return rc;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * The caller must already hold a reference to the page
+ */
+int uv_convert_owned_from_secure(unsigned long paddr)
+{
+	struct page *page = phys_to_page(paddr);
+	int rc;
+
+	get_page(page);
+	rc = uv_convert_from_secure(paddr);
+	if (!rc)
+		clear_bit(PG_arch_1, &page->flags);
+	put_page(page);
+	return rc;
+}
+
+/*
+ * 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_page_secure(struct page *page, struct uv_cb_header *uvcb)
+{
+	int expected, cc = 0;
+
+	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);
+	/*
+	 * If the UVC does not succeed or fail immediately, we don't want to
+	 * loop for long, or we might get stall notifications.
+	 * On the other hand, this is a complex scenario and we are holding a lot of
+	 * locks, so we can't easily sleep and reschedule. We try only once,
+	 * and if the UVC returned busy or partial completion, we return
+	 * -EAGAIN and we let the callers deal with it.
+	 */
+	cc = __uv_call(0, (u64)uvcb);
+	page_ref_unfreeze(page, expected);
+	/*
+	 * Return -ENXIO if the page was not mapped, -EINVAL for other errors.
+	 * If busy or partially completed, return -EAGAIN.
+	 */
+	if (cc == UVC_CC_OK)
+		return 0;
+	else if (cc == UVC_CC_BUSY || cc == UVC_CC_PARTIAL)
+		return -EAGAIN;
+	return uvcb->rc == 0x10a ? -ENXIO : -EINVAL;
+}
+
+/**
+ * should_export_before_import - Determine whether an export is needed
+ * before an import-like operation
+ * @uvcb: the Ultravisor control block of the UVC to be performed
+ * @mm: the mm of the process
+ *
+ * Returns whether an export is needed before every import-like operation.
+ * This is needed for shared pages, which don't trigger a secure storage
+ * exception when accessed from a different guest.
+ *
+ * Although considered as one, the Unpin Page UVC is not an actual import,
+ * so it is not affected.
+ *
+ * No export is needed also when there is only one protected VM, because the
+ * page cannot belong to the wrong VM in that case (there is no "other VM"
+ * it can belong to).
+ *
+ * Return: true if an export is needed before every import, otherwise false.
+ */
+static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm)
+{
+	/*
+	 * The misc feature indicates, among other things, that importing a
+	 * shared page from a different protected VM will automatically also
+	 * transfer its ownership.
+	 */
+	if (uv_has_feature(BIT_UV_FEAT_MISC))
+		return false;
+	if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED)
+		return false;
+	return atomic_read(&mm->context.protected_count) > 1;
+}
+
+/*
+ * 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 = vma_lookup(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;
+	ptep = get_locked_pte(gmap->mm, uaddr, &ptelock);
+	if (!ptep)
+		goto out;
+	if (pte_present(*ptep) && !(pte_val(*ptep) & _PAGE_INVALID) && pte_write(*ptep)) {
+		page = pte_page(*ptep);
+		rc = -EAGAIN;
+		if (trylock_page(page)) {
+			if (should_export_before_import(uvcb, gmap->mm))
+				uv_convert_from_secure(page_to_phys(page));
+			rc = make_page_secure(page, uvcb);
+			unlock_page(page);
+		}
+	}
+	pte_unmap_unlock(ptep, ptelock);
+out:
+	mmap_read_unlock(gmap->mm);
+
+	if (rc == -EAGAIN) {
+		/*
+		 * If we are here because the UVC returned busy or partial
+		 * completion, this is just a useless check, but it is safe.
+		 */
+		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);
+
+/**
+ * gmap_destroy_page - Destroy a guest page.
+ * @gmap: the gmap of the guest
+ * @gaddr: the guest address to destroy
+ *
+ * An attempt will be made to destroy the given guest page. If the attempt
+ * fails, an attempt is made to export the page. If both attempts fail, an
+ * appropriate error is returned.
+ */
+int gmap_destroy_page(struct gmap *gmap, unsigned long gaddr)
+{
+	struct vm_area_struct *vma;
+	unsigned long uaddr;
+	struct page *page;
+	int rc;
+
+	rc = -EFAULT;
+	mmap_read_lock(gmap->mm);
+
+	uaddr = __gmap_translate(gmap, gaddr);
+	if (IS_ERR_VALUE(uaddr))
+		goto out;
+	vma = vma_lookup(gmap->mm, uaddr);
+	if (!vma)
+		goto out;
+	/*
+	 * Huge pages should not be able to become secure
+	 */
+	if (is_vm_hugetlb_page(vma))
+		goto out;
+
+	rc = 0;
+	/* we take an extra reference here */
+	page = follow_page(vma, uaddr, FOLL_WRITE | FOLL_GET);
+	if (IS_ERR_OR_NULL(page))
+		goto out;
+	rc = uv_destroy_owned_page(page_to_phys(page));
+	/*
+	 * Fault handlers can race; it is possible that two CPUs will fault
+	 * on the same secure page. One CPU can destroy the page, reboot,
+	 * re-enter secure mode and import it, while the second CPU was
+	 * stuck at the beginning of the handler. At some point the second
+	 * CPU will be able to progress, and it will not be able to destroy
+	 * the page. In that case we do not want to terminate the process,
+	 * we instead try to export the page.
+	 */
+	if (rc)
+		rc = uv_convert_owned_from_secure(page_to_phys(page));
+	put_page(page);
+out:
+	mmap_read_unlock(gmap->mm);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(gmap_destroy_page);
+
+/*
+ * 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 *buf)
+{
+	return sysfs_emit(buf, "%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_supp_se_hdr_ver(struct kobject *kobj,
+					struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_se_hdr_ver);
+}
+
+static struct kobj_attribute uv_query_supp_se_hdr_ver_attr =
+	__ATTR(supp_se_hdr_ver, 0444, uv_query_supp_se_hdr_ver, NULL);
+
+static ssize_t uv_query_supp_se_hdr_pcf(struct kobject *kobj,
+					struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_se_hdr_pcf);
+}
+
+static struct kobj_attribute uv_query_supp_se_hdr_pcf_attr =
+	__ATTR(supp_se_hdr_pcf, 0444, uv_query_supp_se_hdr_pcf, NULL);
+
+static ssize_t uv_query_dump_cpu_len(struct kobject *kobj,
+				     struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.guest_cpu_stor_len);
+}
+
+static struct kobj_attribute uv_query_dump_cpu_len_attr =
+	__ATTR(uv_query_dump_cpu_len, 0444, uv_query_dump_cpu_len, NULL);
+
+static ssize_t uv_query_dump_storage_state_len(struct kobject *kobj,
+					       struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.conf_dump_storage_state_len);
+}
+
+static struct kobj_attribute uv_query_dump_storage_state_len_attr =
+	__ATTR(dump_storage_state_len, 0444, uv_query_dump_storage_state_len, NULL);
+
+static ssize_t uv_query_dump_finalize_len(struct kobject *kobj,
+					  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.conf_dump_finalize_len);
+}
+
+static struct kobj_attribute uv_query_dump_finalize_len_attr =
+	__ATTR(dump_finalize_len, 0444, uv_query_dump_finalize_len, 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 *buf)
+{
+	return sysfs_emit(buf, "%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 *buf)
+{
+	return sysfs_emit(buf, "%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 *buf)
+{
+	return sysfs_emit(buf, "%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 ssize_t uv_query_supp_att_req_hdr_ver(struct kobject *kobj,
+					     struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_att_req_hdr_ver);
+}
+
+static struct kobj_attribute uv_query_supp_att_req_hdr_ver_attr =
+	__ATTR(supp_att_req_hdr_ver, 0444, uv_query_supp_att_req_hdr_ver, NULL);
+
+static ssize_t uv_query_supp_att_pflags(struct kobject *kobj,
+					struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_att_pflags);
+}
+
+static struct kobj_attribute uv_query_supp_att_pflags_attr =
+	__ATTR(supp_att_pflags, 0444, uv_query_supp_att_pflags, NULL);
+
+static ssize_t uv_query_supp_add_secret_req_ver(struct kobject *kobj,
+						struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_add_secret_req_ver);
+}
+
+static struct kobj_attribute uv_query_supp_add_secret_req_ver_attr =
+	__ATTR(supp_add_secret_req_ver, 0444, uv_query_supp_add_secret_req_ver, NULL);
+
+static ssize_t uv_query_supp_add_secret_pcf(struct kobject *kobj,
+					    struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_add_secret_pcf);
+}
+
+static struct kobj_attribute uv_query_supp_add_secret_pcf_attr =
+	__ATTR(supp_add_secret_pcf, 0444, uv_query_supp_add_secret_pcf, NULL);
+
+static ssize_t uv_query_supp_secret_types(struct kobject *kobj,
+					  struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%lx\n", uv_info.supp_secret_types);
+}
+
+static struct kobj_attribute uv_query_supp_secret_types_attr =
+	__ATTR(supp_secret_types, 0444, uv_query_supp_secret_types, NULL);
+
+static ssize_t uv_query_max_secrets(struct kobject *kobj,
+				    struct kobj_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", uv_info.max_secrets);
+}
+
+static struct kobj_attribute uv_query_max_secrets_attr =
+	__ATTR(max_secrets, 0444, uv_query_max_secrets, 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,
+	&uv_query_supp_se_hdr_ver_attr.attr,
+	&uv_query_supp_se_hdr_pcf_attr.attr,
+	&uv_query_dump_storage_state_len_attr.attr,
+	&uv_query_dump_finalize_len_attr.attr,
+	&uv_query_dump_cpu_len_attr.attr,
+	&uv_query_supp_att_req_hdr_ver_attr.attr,
+	&uv_query_supp_att_pflags_attr.attr,
+	&uv_query_supp_add_secret_req_ver_attr.attr,
+	&uv_query_supp_add_secret_pcf_attr.attr,
+	&uv_query_supp_secret_types_attr.attr,
+	&uv_query_max_secrets_attr.attr,
+	NULL,
+};
+
+static struct attribute_group uv_query_attr_group = {
+	.attrs = uv_query_attrs,
+};
+
+static ssize_t uv_is_prot_virt_guest(struct kobject *kobj,
+				     struct kobj_attribute *attr, char *buf)
+{
+	int val = 0;
+
+#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
+	val = prot_virt_guest;
+#endif
+	return sysfs_emit(buf, "%d\n", val);
+}
+
+static ssize_t uv_is_prot_virt_host(struct kobject *kobj,
+				    struct kobj_attribute *attr, char *buf)
+{
+	int val = 0;
+
+#if IS_ENABLED(CONFIG_KVM)
+	val = prot_virt_host;
+#endif
+
+	return sysfs_emit(buf, "%d\n", val);
+}
+
+static struct kobj_attribute uv_prot_virt_guest =
+	__ATTR(prot_virt_guest, 0444, uv_is_prot_virt_guest, NULL);
+
+static struct kobj_attribute uv_prot_virt_host =
+	__ATTR(prot_virt_host, 0444, uv_is_prot_virt_host, NULL);
+
+static const struct attribute *uv_prot_virt_attrs[] = {
+	&uv_prot_virt_guest.attr,
+	&uv_prot_virt_host.attr,
+	NULL,
+};
+
+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;
+
+	rc = sysfs_create_files(uv_kobj, uv_prot_virt_attrs);
+	if (rc)
+		goto out_kobj;
+
+	uv_query_kset = kset_create_and_add("query", NULL, uv_kobj);
+	if (!uv_query_kset) {
+		rc = -ENOMEM;
+		goto out_ind_files;
+	}
+
+	rc = sysfs_create_group(&uv_query_kset->kobj, &uv_query_attr_group);
+	if (!rc)
+		return 0;
+
+	kset_unregister(uv_query_kset);
+out_ind_files:
+	sysfs_remove_files(uv_kobj, uv_prot_virt_attrs);
+out_kobj:
+	kobject_del(uv_kobj);
+	kobject_put(uv_kobj);
+	return rc;
+}
+device_initcall(uv_info_init);
+#endif