Merge branch 'pvbase' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

s390 base parts (non kvm) for protvirt

Documentation/admin-guide/kernel-parameters.txt

@@ -3795,6 +3795,11 @@
 			before loading.
 			See Documentation/admin-guide/blockdev/ramdisk.rst.
 
+	prot_virt=	[S390] enable hosting protected virtual machines
+			isolated from the hypervisor (if hardware supports
+			that).
+			Format: <bool>
+
 	psi=		[KNL] Enable or disable pressure stall information
 			tracking.
 			Format: <bool>

arch/s390/boot/Makefile

@@ -37,7 +37,7 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char
 obj-y	:= head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o
 obj-y	+= string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o
 obj-y	+= version.o pgm_check_info.o ctype.o text_dma.o
-obj-$(CONFIG_PROTECTED_VIRTUALIZATION_GUEST)	+= uv.o
+obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE))	+= uv.o
 obj-$(CONFIG_RELOCATABLE)	+= machine_kexec_reloc.o
 obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr.o
 targets	:= bzImage startup.a section_cmp.boot.data section_cmp.boot.preserved.data $(obj-y)

arch/s390/boot/uv.c

@@ -3,7 +3,13 @@
 #include <asm/facility.h>
 #include <asm/sections.h>
 
+/* will be used in arch/s390/kernel/uv.c */
+#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 int __bootdata_preserved(prot_virt_guest);
+#endif
+#if IS_ENABLED(CONFIG_KVM)
+struct uv_info __bootdata_preserved(uv_info);
+#endif
 
 void uv_query_info(void)
 {
@@ -19,7 +25,21 @@ void uv_query_info(void)
 	if (uv_call(0, (uint64_t)&uvcb) && uvcb.header.rc != 0x100)
 		return;
 
+	if (IS_ENABLED(CONFIG_KVM)) {
+		memcpy(uv_info.inst_calls_list, uvcb.inst_calls_list, sizeof(uv_info.inst_calls_list));
+		uv_info.uv_base_stor_len = uvcb.uv_base_stor_len;
+		uv_info.guest_base_stor_len = uvcb.conf_base_phys_stor_len;
+		uv_info.guest_virt_base_stor_len = uvcb.conf_base_virt_stor_len;
+		uv_info.guest_virt_var_stor_len = uvcb.conf_virt_var_stor_len;
+		uv_info.guest_cpu_stor_len = uvcb.cpu_stor_len;
+		uv_info.max_sec_stor_addr = ALIGN(uvcb.max_guest_stor_addr, PAGE_SIZE);
+		uv_info.max_num_sec_conf = uvcb.max_num_sec_conf;
+		uv_info.max_guest_cpus = uvcb.max_guest_cpus;
+	}
+
+#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 	if (test_bit_inv(BIT_UVC_CMD_SET_SHARED_ACCESS, (unsigned long *)uvcb.inst_calls_list) &&
 	    test_bit_inv(BIT_UVC_CMD_REMOVE_SHARED_ACCESS, (unsigned long *)uvcb.inst_calls_list))
 		prot_virt_guest = 1;
+#endif
 }

arch/s390/include/asm/gmap.h

@@ -9,6 +9,7 @@
 #ifndef _ASM_S390_GMAP_H
 #define _ASM_S390_GMAP_H
 
+#include <linux/radix-tree.h>
 #include <linux/refcount.h>
 
 /* Generic bits for GMAP notification on DAT table entry changes. */
@@ -31,6 +32,7 @@
  * @table: pointer to the page directory
  * @asce: address space control element for gmap page table
  * @pfault_enabled: defines if pfaults are applicable for the guest
+ * @guest_handle: protected virtual machine handle for the ultravisor
  * @host_to_rmap: radix tree with gmap_rmap lists
  * @children: list of shadow gmap structures
  * @pt_list: list of all page tables used in the shadow guest address space
@@ -54,6 +56,8 @@ struct gmap {
 	unsigned long asce_end;
 	void *private;
 	bool pfault_enabled;
+	/* only set for protected virtual machines */
+	unsigned long guest_handle;
 	/* Additional data for shadow guest address spaces */
 	struct radix_tree_root host_to_rmap;
 	struct list_head children;

arch/s390/include/asm/mmu.h

@@ -16,6 +16,8 @@ typedef struct {
 	unsigned long asce;
 	unsigned long asce_limit;
 	unsigned long vdso_base;
+	/* The mmu context belongs to a secure guest. */
+	atomic_t is_protected;
 	/*
 	 * The following bitfields need a down_write on the mm
 	 * semaphore when they are written to. As they are only

arch/s390/include/asm/mmu_context.h

@@ -23,6 +23,7 @@ static inline int init_new_context(struct task_struct *tsk,
 	INIT_LIST_HEAD(&mm->context.gmap_list);
 	cpumask_clear(&mm->context.cpu_attach_mask);
 	atomic_set(&mm->context.flush_count, 0);
+	atomic_set(&mm->context.is_protected, 0);
 	mm->context.gmap_asce = 0;
 	mm->context.flush_mm = 0;
 	mm->context.compat_mm = test_thread_flag(TIF_31BIT);

arch/s390/include/asm/page.h

@@ -153,6 +153,11 @@ static inline int devmem_is_allowed(unsigned long pfn)
 #define HAVE_ARCH_FREE_PAGE
 #define HAVE_ARCH_ALLOC_PAGE
 
+#if IS_ENABLED(CONFIG_PGSTE)
+int arch_make_page_accessible(struct page *page);
+#define HAVE_ARCH_MAKE_PAGE_ACCESSIBLE
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #define __PAGE_OFFSET		0x0UL

arch/s390/include/asm/pgtable.h

@@ -19,6 +19,7 @@
 #include <linux/atomic.h>
 #include <asm/bug.h>
 #include <asm/page.h>
+#include <asm/uv.h>
 
 extern pgd_t swapper_pg_dir[];
 extern void paging_init(void);
@@ -520,6 +521,15 @@ static inline int mm_has_pgste(struct mm_struct *mm)
 	return 0;
 }
 
+static inline int mm_is_protected(struct mm_struct *mm)
+{
+#ifdef CONFIG_PGSTE
+	if (unlikely(atomic_read(&mm->context.is_protected)))
+		return 1;
+#endif
+	return 0;
+}
+
 static inline int mm_alloc_pgste(struct mm_struct *mm)
 {
 #ifdef CONFIG_PGSTE
@@ -1061,7 +1071,12 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pte_t *ptep)
 {
-	return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
+	pte_t res;
+
+	res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
+	if (mm_is_protected(mm) && pte_present(res))
+		uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+	return res;
 }
 
 #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
@@ -1073,7 +1088,12 @@ void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
 static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
 				     unsigned long addr, pte_t *ptep)
 {
-	return ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID));
+	pte_t res;
+
+	res = ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID));
+	if (mm_is_protected(vma->vm_mm) && pte_present(res))
+		uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+	return res;
 }
 
 /*
@@ -1088,12 +1108,17 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 					    unsigned long addr,
 					    pte_t *ptep, int full)
 {
+	pte_t res;
+
 	if (full) {
-		pte_t pte = *ptep;
+		res = *ptep;
 		*ptep = __pte(_PAGE_INVALID);
-		return pte;
+	} else {
+		res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
 	}
-	return ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
+	if (mm_is_protected(mm) && pte_present(res))
+		uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+	return res;
 }
 
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT

arch/s390/include/asm/uv.h

@@ -15,6 +15,7 @@
 #include <linux/errno.h>
 #include <linux/bug.h>
 #include <asm/page.h>
+#include <asm/gmap.h>
 
 #define UVC_RC_EXECUTED		0x0001
 #define UVC_RC_INV_CMD		0x0002
@@ -23,14 +24,24 @@
 #define UVC_RC_NO_RESUME	0x0007
 
 #define UVC_CMD_QUI			0x0001
+#define UVC_CMD_INIT_UV			0x000f
+#define UVC_CMD_CONV_TO_SEC_STOR	0x0200
+#define UVC_CMD_CONV_FROM_SEC_STOR	0x0201
+#define UVC_CMD_PIN_PAGE_SHARED		0x0341
+#define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
 #define UVC_CMD_SET_SHARED_ACCESS	0x1000
 #define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
 
 /* Bits in installed uv calls */
 enum uv_cmds_inst {
 	BIT_UVC_CMD_QUI = 0,
+	BIT_UVC_CMD_INIT_UV = 1,
+	BIT_UVC_CMD_CONV_TO_SEC_STOR = 6,
+	BIT_UVC_CMD_CONV_FROM_SEC_STOR = 7,
 	BIT_UVC_CMD_SET_SHARED_ACCESS = 8,
 	BIT_UVC_CMD_REMOVE_SHARED_ACCESS = 9,
+	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
+	BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22,
 };
 
 struct uv_cb_header {
@@ -44,7 +55,40 @@ struct uv_cb_qui {
 	struct uv_cb_header header;
 	u64 reserved08;
 	u64 inst_calls_list[4];
-	u64 reserved30[15];
+	u64 reserved30[2];
+	u64 uv_base_stor_len;
+	u64 reserved48;
+	u64 conf_base_phys_stor_len;
+	u64 conf_base_virt_stor_len;
+	u64 conf_virt_var_stor_len;
+	u64 cpu_stor_len;
+	u32 reserved70[3];
+	u32 max_num_sec_conf;
+	u64 max_guest_stor_addr;
+	u8  reserved88[158 - 136];
+	u16 max_guest_cpus;
+	u8  reserveda0[200 - 160];
+} __packed __aligned(8);
+
+struct uv_cb_init {
+	struct uv_cb_header header;
+	u64 reserved08[2];
+	u64 stor_origin;
+	u64 stor_len;
+	u64 reserved28[4];
+} __packed __aligned(8);
+
+struct uv_cb_cts {
+	struct uv_cb_header header;
+	u64 reserved08[2];
+	u64 guest_handle;
+	u64 gaddr;
+} __packed __aligned(8);
+
+struct uv_cb_cfs {
+	struct uv_cb_header header;
+	u64 reserved08[2];
+	u64 paddr;
 } __packed __aligned(8);
 
 struct uv_cb_share {
@@ -69,6 +113,20 @@ static inline int uv_call(unsigned long r1, unsigned long r2)
 	return cc;
 }
 
+struct uv_info {
+	unsigned long inst_calls_list[4];
+	unsigned long uv_base_stor_len;
+	unsigned long guest_base_stor_len;
+	unsigned long guest_virt_base_stor_len;
+	unsigned long guest_virt_var_stor_len;
+	unsigned long guest_cpu_stor_len;
+	unsigned long max_sec_stor_addr;
+	unsigned int max_num_sec_conf;
+	unsigned short max_guest_cpus;
+};
+
+extern struct uv_info uv_info;
+
 #ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 extern int prot_virt_guest;
 
@@ -121,11 +179,40 @@ static inline int uv_remove_shared(unsigned long addr)
 	return share(addr, UVC_CMD_REMOVE_SHARED_ACCESS);
 }
 
-void uv_query_info(void);
 #else
 #define is_prot_virt_guest() 0
 static inline int uv_set_shared(unsigned long addr) { return 0; }
 static inline int uv_remove_shared(unsigned long addr) { return 0; }
+#endif
+
+#if IS_ENABLED(CONFIG_KVM)
+extern int prot_virt_host;
+
+static inline int is_prot_virt_host(void)
+{
+	return prot_virt_host;
+}
+
+int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb);
+int uv_convert_from_secure(unsigned long paddr);
+int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr);
+
+void setup_uv(void);
+void adjust_to_uv_max(unsigned long *vmax);
+#else
+#define is_prot_virt_host() 0
+static inline void setup_uv(void) {}
+static inline void adjust_to_uv_max(unsigned long *vmax) {}
+
+static inline int uv_convert_from_secure(unsigned long paddr)
+{
+	return 0;
+}
+#endif
+
+#if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || IS_ENABLED(CONFIG_KVM)
+void uv_query_info(void);
+#else
 static inline void uv_query_info(void) {}
 #endif
 

arch/s390/kernel/Makefile

@@ -78,6 +78,7 @@ obj-$(CONFIG_PERF_EVENTS)	+= perf_cpum_cf_events.o perf_regs.o
 obj-$(CONFIG_PERF_EVENTS)	+= perf_cpum_cf_diag.o
 
 obj-$(CONFIG_TRACEPOINTS)	+= trace.o
+obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE))	+= uv.o
 
 # vdso
 obj-y				+= vdso64/

arch/s390/kernel/entry.h

@@ -24,6 +24,8 @@ asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
 
 void do_protection_exception(struct pt_regs *regs);
 void do_dat_exception(struct pt_regs *regs);
+void do_secure_storage_access(struct pt_regs *regs);
+void do_non_secure_storage_access(struct pt_regs *regs);
 
 void addressing_exception(struct pt_regs *regs);
 void data_exception(struct pt_regs *regs);

arch/s390/kernel/pgm_check.S

@@ -78,8 +78,8 @@ PGM_CHECK(do_dat_exception)		/* 39 */
 PGM_CHECK(do_dat_exception)		/* 3a */
 PGM_CHECK(do_dat_exception)		/* 3b */
 PGM_CHECK_DEFAULT			/* 3c */
-PGM_CHECK_DEFAULT			/* 3d */
-PGM_CHECK_DEFAULT			/* 3e */
+PGM_CHECK(do_secure_storage_access)	/* 3d */
+PGM_CHECK(do_non_secure_storage_access)	/* 3e */
 PGM_CHECK_DEFAULT			/* 3f */
 PGM_CHECK(monitor_event_exception)	/* 40 */
 PGM_CHECK_DEFAULT			/* 41 */

arch/s390/kernel/setup.c

@@ -92,10 +92,6 @@ char elf_platform[ELF_PLATFORM_SIZE];
 
 unsigned long int_hwcap = 0;
 
-#ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
-int __bootdata_preserved(prot_virt_guest);
-#endif
-
 int __bootdata(noexec_disabled);
 int __bootdata(memory_end_set);
 unsigned long __bootdata(memory_end);
@@ -564,6 +560,9 @@ static void __init setup_memory_end(void)
 			vmax = _REGION1_SIZE; /* 4-level kernel page table */
 	}
 
+	if (is_prot_virt_host())
+		adjust_to_uv_max(&vmax);
+
 	/* module area is at the end of the kernel address space. */
 	MODULES_END = vmax;
 	MODULES_VADDR = MODULES_END - MODULES_LEN;
@@ -1138,6 +1137,8 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	memblock_trim_memory(1UL << (MAX_ORDER - 1 + PAGE_SHIFT));
 
+	if (is_prot_virt_host())
+		setup_uv();
 	setup_memory_end();
 	setup_memory();
 	dma_contiguous_reserve(memory_end);

arch/s390/kernel/uv.c

+// 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
+
+#if IS_ENABLED(CONFIG_KVM)
+int prot_virt_host;
+EXPORT_SYMBOL(prot_virt_host);
+struct uv_info __bootdata_preserved(uv_info);
+EXPORT_SYMBOL(uv_info);
+
+static int __init prot_virt_setup(char *val)
+{
+	bool enabled;
+	int rc;
+
+	rc = kstrtobool(val, &enabled);
+	if (!rc && enabled)
+		prot_virt_host = 1;
+
+	if (is_prot_virt_guest() && prot_virt_host) {
+		prot_virt_host = 0;
+		pr_warn("Protected virtualization not available in protected guests.");
+	}
+
+	if (prot_virt_host && !test_facility(158)) {
+		prot_virt_host = 0;
+		pr_warn("Protected virtualization not supported by the hardware.");
+	}
+
+	return rc;
+}
+early_param("prot_virt", prot_virt_setup);
+
+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;
+
+	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)
+{
+	*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 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;
+	down_read(&gmap->mm->mmap_sem);
+
+	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:
+	up_read(&gmap->mm->mmap_sem);
+
+	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 snprintf(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_max_guest_cpus(struct kobject *kobj,
+				       struct kobj_attribute *attr, char *page)
+{
+	return snprintf(page, PAGE_SIZE, "%d\n",
+			uv_info.max_guest_cpus);
+}
+
+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 snprintf(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 snprintf(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_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

arch/s390/mm/fault.c

@@ -38,6 +38,7 @@
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
 #include <asm/facility.h>
+#include <asm/uv.h>
 #include "../kernel/entry.h"
 
 #define __FAIL_ADDR_MASK -4096L
@@ -816,3 +817,80 @@ static int __init pfault_irq_init(void)
 early_initcall(pfault_irq_init);
 
 #endif /* CONFIG_PFAULT */
+
+#if IS_ENABLED(CONFIG_PGSTE)
+void do_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct vm_area_struct *vma;
+	struct mm_struct *mm;
+	struct page *page;
+	int rc;
+
+	switch (get_fault_type(regs)) {
+	case USER_FAULT:
+		mm = current->mm;
+		down_read(&mm->mmap_sem);
+		vma = find_vma(mm, addr);
+		if (!vma) {
+			up_read(&mm->mmap_sem);
+			do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+			break;
+		}
+		page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);
+		if (IS_ERR_OR_NULL(page)) {
+			up_read(&mm->mmap_sem);
+			break;
+		}
+		if (arch_make_page_accessible(page))
+			send_sig(SIGSEGV, current, 0);
+		put_page(page);
+		up_read(&mm->mmap_sem);
+		break;
+	case KERNEL_FAULT:
+		page = phys_to_page(addr);
+		if (unlikely(!try_get_page(page)))
+			break;
+		rc = arch_make_page_accessible(page);
+		put_page(page);
+		if (rc)
+			BUG();
+		break;
+	case VDSO_FAULT:
+		/* fallthrough */
+	case GMAP_FAULT:
+		/* fallthrough */
+	default:
+		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+	}
+}
+NOKPROBE_SYMBOL(do_secure_storage_access);
+
+void do_non_secure_storage_access(struct pt_regs *regs)
+{
+	unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
+	struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
+
+	if (get_fault_type(regs) != GMAP_FAULT) {
+		do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
+		WARN_ON_ONCE(1);
+		return;
+	}
+
+	if (gmap_convert_to_secure(gmap, gaddr) == -EINVAL)
+		send_sig(SIGSEGV, current, 0);
+}
+NOKPROBE_SYMBOL(do_non_secure_storage_access);
+
+#else
+void do_secure_storage_access(struct pt_regs *regs)
+{
+	default_trap_handler(regs);
+}
+
+void do_non_secure_storage_access(struct pt_regs *regs)
+{
+	default_trap_handler(regs);
+}
+#endif