diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index e30ea907abb6..097abca7784c 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -168,4 +168,13 @@ static inline void pks_update_protection(int pkey, unsigned long protection)
 }
 #endif /* CONFIG_ARCH_HAS_SUPERVISOR_PKEYS */
 
+#if defined(CONFIG_PKS_TESTING)
+bool pks_test_armed_and_clear(void);
+#else
+static inline bool pks_test_armed_and_clear(void)
+{
+	return false;
+}
+#endif
+
 #endif /*_ASM_X86_PKEYS_H */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 1ead568c0101..483fbf5b7957 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -18,6 +18,7 @@
 #include <linux/uaccess.h>		/* faulthandler_disabled()	*/
 #include <linux/efi.h>			/* efi_recover_from_page_fault()*/
 #include <linux/mm_types.h>
+#include <linux/pkeys.h>
 
 #include <asm/cpufeature.h>		/* boot_cpu_has, ...		*/
 #include <asm/traps.h>			/* dotraplinkage, ...		*/
@@ -1105,11 +1106,18 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
 		   unsigned long address)
 {
 	/*
-	 * Protection keys exceptions only happen on user pages.  We
-	 * have no user pages in the kernel portion of the address
-	 * space, so do not expect them here.
+	 * If we get a protection key exception it could be because we are
+	 * running the PKS test.  If so, pks_test_armed_and_clear() will clear
+	 * the protection mechanism and we can safely return.
+	 *
+	 * Otherwise we warn the user that something has gone wrong and
+	 * continue with the fault.
 	 */
-	WARN_ON_ONCE(hw_error_code & X86_PF_PK);
+	if (hw_error_code & X86_PF_PK) {
+		if (pks_test_armed_and_clear())
+			return;
+		WARN_ON_ONCE(hw_error_code & X86_PF_PK);
+	}
 
 	/* Was the fault spurious, caused by lazy TLB invalidation? */
 	if (spurious_kernel_fault(hw_error_code, address))
diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
index e4bff77d7b49..1d84ab7c12d4 100644
--- a/include/linux/pkeys.h
+++ b/include/linux/pkeys.h
@@ -48,6 +48,10 @@ static inline void copy_init_pkru_to_fpregs(void)
 {
 }
 
+static inline bool pks_test_armed_and_clear(void)
+{
+	return false;
+}
 #endif /* ! CONFIG_ARCH_HAS_PKEYS */
 
 #ifndef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ad9210d70a1..aa876ebb4c8b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2329,6 +2329,18 @@ config HYPERV_TESTING
 	help
 	  Select this option to enable Hyper-V vmbus testing.
 
+config PKS_TESTING
+	bool "PKey(S)upervisor testing"
+	default n
+	depends on ARCH_HAS_SUPERVISOR_PKEYS
+	help
+	  Select this option to enable testing of PKS core software and
+	  hardware.  The PKS core provides a mechanism to allocate keys as well
+	  as maintain the protection settings across context switches.
+	  Answer N if you don't know what supervisor keys are.
+
+	  If unsure, say N.
+
 endmenu # "Kernel Testing and Coverage"
 
 endmenu # Kernel hacking
diff --git a/lib/Makefile b/lib/Makefile
index b1c42c10073b..667dea28cf7b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -318,3 +318,6 @@ obj-$(CONFIG_OBJAGG) += objagg.o
 # KUnit tests
 obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
 obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+
+# PKS test
+obj-y += pks/
diff --git a/lib/pks/Makefile b/lib/pks/Makefile
new file mode 100644
index 000000000000..7d1df7563db9
--- /dev/null
+++ b/lib/pks/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_PKS_TESTING) += pks_test.o
diff --git a/lib/pks/pks_test.c b/lib/pks/pks_test.c
new file mode 100644
index 000000000000..6d8172734f97
--- /dev/null
+++ b/lib/pks/pks_test.c
@@ -0,0 +1,452 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright(c) 2020 Intel Corporation. All rights reserved.
+ *
+ * Implement PKS testing
+ * Access to run this test can be with a command line parameter
+ * ("pks-test-on-boot") or more detailed tests can be triggered through:
+ *
+ *    /sys/kernel/debug/x86/run_pks
+ *
+ *  debugfs controls are:
+ *
+ *  '0' -- Run access tests with a single pkey
+ *
+ *  '1' -- Set up the pkey register with no access for the pkey allocated to
+ *         this fd
+ *  '2' -- Check that the pkey register updated in '1' is still the same.  (To
+ *         be used after a forced context switch.)
+ *
+ *  '3' -- Allocate all pkeys possible and run tests on each pkey allocated.
+ *         DEFAULT when run at boot.
+ *
+ *  Closing the fd will cleanup and release the pkey.
+ *
+ *  A companion user space program is provided in:
+ *
+ *          .../tools/testing/selftests/x86/test_pks.c
+ *
+ *  which will better test the context switching.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/pgtable.h>
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/pkeys.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#define PKS_TEST_MEM_SIZE (PAGE_SIZE)
+
+/*
+ * run_on_boot default '= false' which checkpatch complains about initializing;
+ * so we don't
+ */
+static bool run_on_boot;
+static struct dentry *pks_test_dentry;
+
+/*
+ * We must lock the following globals for brief periods while the fault handler
+ * checks/updates them.
+ */
+static DEFINE_SPINLOCK(test_lock);
+static int test_armed_key;
+static unsigned long prev_cnt;
+static unsigned long fault_cnt;
+
+struct pks_test_ctx {
+	bool pass;
+	bool pks_cpu_enabled;
+	int pkey;
+	char data[64];
+};
+
+static pte_t *walk_table(void *ptr)
+{
+	struct page *page = NULL;
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+	pte_t *ret = NULL;
+
+	pgdp = pgd_offset_k((unsigned long)ptr);
+	if (pgd_none(*pgdp) || pgd_bad(*pgdp))
+		goto error;
+
+	p4dp = p4d_offset(pgdp, (unsigned long)ptr);
+	if (p4d_none(*p4dp) || p4d_bad(*p4dp))
+		goto error;
+
+	pudp = pud_offset(p4dp, (unsigned long)ptr);
+	if (pud_none(*pudp) || pud_bad(*pudp))
+		goto error;
+
+	pmdp = pmd_offset(pudp, (unsigned long)ptr);
+	if (pmd_none(*pmdp) || pmd_bad(*pmdp))
+		goto error;
+
+	ret = pte_offset_map(pmdp, (unsigned long)ptr);
+	if (pte_present(*ret)) {
+		page = pte_page(*ret);
+		if (!page) {
+			pte_unmap(ret);
+			goto error;
+		}
+		pr_info("page 0x%lx; flags 0x%lx\n",
+		       (unsigned long)page, page->flags);
+	}
+
+error:
+	return ret;
+}
+
+/**
+ * pks_test_armed_and_clear() is exported so that the fault handler can detect
+ * and report back status of intentional faults.
+ *
+ * NOTE: It clears the protection key from the page such that the fault handler
+ * will not re-trigger.
+ */
+bool pks_test_armed_and_clear(void)
+{
+	bool armed = (test_armed_key != 0);
+
+	if (armed) {
+		/* Enable read and write to stop faults */
+		pks_update_protection(test_armed_key, 0);
+		fault_cnt++;
+	}
+
+	return armed;
+}
+EXPORT_SYMBOL(pks_test_armed_and_clear);
+
+static bool exception_caught(void)
+{
+	bool ret = (fault_cnt != prev_cnt);
+
+	prev_cnt = fault_cnt;
+	return ret;
+}
+
+static void report_pkey_settings(void *unused)
+{
+	u8 pkey;
+	unsigned long long msr = 0;
+	unsigned int cpu = smp_processor_id();
+
+	rdmsrl(MSR_IA32_PKRS, msr);
+
+	pr_info("for CPU %d : 0x%llx\n", cpu, msr);
+	for (pkey = 0; pkey < PKS_NUM_KEYS; pkey++) {
+		int ad, wd;
+
+		ad = (msr >> (pkey * PKR_BITS_PER_PKEY)) & PKEY_DISABLE_ACCESS;
+		wd = (msr >> (pkey * PKR_BITS_PER_PKEY)) & PKEY_DISABLE_WRITE;
+		pr_info("   %u: A:%d W:%d\n", pkey, ad, wd);
+	}
+}
+
+struct pks_access_test {
+	int ad;
+	int wd;
+	bool write;
+	bool exception;
+};
+
+static struct pks_access_test pkey_test_ary[] = {
+	/*  disable both */
+	{ PKEY_DISABLE_ACCESS, PKEY_DISABLE_WRITE,   true,  true },
+	{ PKEY_DISABLE_ACCESS, PKEY_DISABLE_WRITE,   false, true },
+
+	/*  enable both */
+	{ 0, 0, true,  false },
+	{ 0, 0, false, false },
+
+	/*  enable read only */
+	{ 0, PKEY_DISABLE_WRITE,  true,  true },
+	{ 0, PKEY_DISABLE_WRITE,  false, false },
+};
+
+static int run_access_test(struct pks_test_ctx *ctx,
+			   struct pks_access_test *test,
+			   void *ptr)
+{
+	int ret = 0;
+	bool exception;
+
+	pks_update_protection(ctx->pkey, test->ad | test->wd);
+
+	spin_lock(&test_lock);
+	test_armed_key = ctx->pkey;
+
+	if (test->write)
+		memcpy(ptr, ctx->data, 8);
+	else
+		memcpy(ctx->data, ptr, 8);
+
+	exception = exception_caught();
+
+	test_armed_key = 0;
+	spin_unlock(&test_lock);
+
+	if (test->exception != exception) {
+		pr_err("pkey test FAILED: ad %d; wd %d; write %s; exception %s != %s\n",
+			test->ad, test->wd,
+			test->write ? "TRUE" : "FALSE",
+			test->exception ? "TRUE" : "FALSE",
+			exception ? "TRUE" : "FALSE");
+		ret = -EFAULT;
+	}
+
+	return ret;
+}
+
+static void test_mem_access(struct pks_test_ctx *ctx)
+{
+	int i, rc;
+	u8 pkey;
+	void *ptr = NULL;
+	pte_t *ptep;
+
+	ptr = __vmalloc_node_range(PKS_TEST_MEM_SIZE, 1, VMALLOC_START, VMALLOC_END,
+				   GFP_KERNEL, PAGE_KERNEL_PKEY(ctx->pkey),
+				   0, NUMA_NO_NODE, __builtin_return_address(0));
+	if (!ptr) {
+		pr_err("Failed to vmalloc page???\n");
+		ctx->pass = false;
+		return;
+	}
+
+	ptep = walk_table(ptr);
+	if (!ptep) {
+		pr_err("Failed to walk table???\n");
+		ctx->pass = false;
+		goto done;
+	}
+
+	pkey = pte_flags_pkey(ptep->pte);
+	pr_info("ptep flags 0x%lx pkey %u\n",
+	       (unsigned long)ptep->pte, pkey);
+
+	if (pkey != ctx->pkey) {
+		pr_err("invalid pkey found: %u, test_pkey: %u\n",
+			pkey, ctx->pkey);
+		ctx->pass = false;
+		goto unmap;
+	}
+
+	if (!ctx->pks_cpu_enabled) {
+		pr_err("not CPU enabled; skipping access tests...\n");
+		ctx->pass = true;
+		goto unmap;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(pkey_test_ary); i++) {
+		rc = run_access_test(ctx, &pkey_test_ary[i], ptr);
+
+		/*  only save last error is fine */
+		if (rc)
+			ctx->pass = false;
+	}
+
+unmap:
+	pte_unmap(ptep);
+done:
+	vfree(ptr);
+}
+
+static void pks_run_test(struct pks_test_ctx *ctx)
+{
+	ctx->pass = true;
+
+	pr_info("\n");
+	pr_info("\n");
+	pr_info("     ***** BEGIN: Testing (CPU enabled : %s) *****\n",
+		ctx->pks_cpu_enabled ? "TRUE" : "FALSE");
+
+	if (ctx->pks_cpu_enabled)
+		on_each_cpu(report_pkey_settings, NULL, 1);
+
+	pr_info("           BEGIN: pkey %d Testing\n", ctx->pkey);
+	test_mem_access(ctx);
+	pr_info("           END: PAGE_KERNEL_PKEY Testing : %s\n",
+		ctx->pass ? "PASS" : "FAIL");
+
+	pr_info("     ***** END: Testing *****\n");
+	pr_info("\n");
+	pr_info("\n");
+}
+
+static ssize_t pks_read_file(struct file *file, char __user *user_buf,
+			     size_t count, loff_t *ppos)
+{
+	struct pks_test_ctx *ctx = file->private_data;
+	char buf[32];
+	unsigned int len;
+
+	if (!ctx)
+		len = sprintf(buf, "not run\n");
+	else
+		len = sprintf(buf, "%s\n", ctx->pass ? "PASS" : "FAIL");
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static struct pks_test_ctx *alloc_ctx(const char *name)
+{
+	struct pks_test_ctx *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+
+	if (!ctx) {
+		pr_err("Failed to allocate memory for test context\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	ctx->pkey = pks_key_alloc(name);
+	if (ctx->pkey <= 0) {
+		pr_err("Failed to allocate memory for test context\n");
+		kfree(ctx);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	ctx->pks_cpu_enabled = cpu_feature_enabled(X86_FEATURE_PKS);
+	sprintf(ctx->data, "%s", "DEADBEEF");
+	return ctx;
+}
+
+static void free_ctx(struct pks_test_ctx *ctx)
+{
+	pks_key_free(ctx->pkey);
+	kfree(ctx);
+}
+
+static void run_all(void)
+{
+	struct pks_test_ctx *ctx[PKS_NUM_KEYS];
+	static char name[PKS_NUM_KEYS][64];
+	int i;
+
+	for (i = 1; i < PKS_NUM_KEYS; i++) {
+		sprintf(name[i], "pks ctx %d", i);
+		ctx[i] = alloc_ctx((const char *)name[i]);
+	}
+
+	for (i = 1; i < PKS_NUM_KEYS; i++) {
+		if (!IS_ERR(ctx[i]))
+			pks_run_test(ctx[i]);
+	}
+
+	for (i = 1; i < PKS_NUM_KEYS; i++) {
+		if (!IS_ERR(ctx[i]))
+			free_ctx(ctx[i]);
+	}
+}
+
+static ssize_t pks_write_file(struct file *file, const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	char buf[2];
+	struct pks_test_ctx *ctx = file->private_data;
+
+	if (copy_from_user(buf, user_buf, 1))
+		return -EFAULT;
+	buf[1] = '\0';
+
+	/*
+	 * Test "3" will test allocating all keys. Do it first without
+	 * using "ctx".
+	 */
+	if (!strcmp(buf, "3"))
+		run_all();
+
+	if (!ctx) {
+		ctx = alloc_ctx("pks test");
+		if (IS_ERR(ctx))
+			return -ENOMEM;
+		file->private_data = ctx;
+	}
+
+	if (!strcmp(buf, "0"))
+		pks_run_test(ctx);
+
+	/* start of context switch test */
+	if (!strcmp(buf, "1")) {
+		/* Ensure a known state to test context switch */
+		pks_update_protection(ctx->pkey,
+				      PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE);
+	}
+
+	/* After context switch msr should be restored */
+	if (!strcmp(buf, "2") && ctx->pks_cpu_enabled) {
+		unsigned long reg_pkrs;
+		int access;
+
+		rdmsrl(MSR_IA32_PKRS, reg_pkrs);
+
+		access = (reg_pkrs >> (ctx->pkey * PKR_BITS_PER_PKEY)) &
+			  PKEY_ACCESS_MASK;
+		if (access != (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)) {
+			ctx->pass = false;
+			pr_err("Context switch check failed\n");
+		}
+	}
+
+	return count;
+}
+
+static int pks_release_file(struct inode *inode, struct file *file)
+{
+	struct pks_test_ctx *ctx = file->private_data;
+
+	if (!ctx)
+		return 0;
+
+	free_ctx(ctx);
+	return 0;
+}
+
+static const struct file_operations fops_init_pks = {
+	.read = pks_read_file,
+	.write = pks_write_file,
+	.llseek = default_llseek,
+	.release = pks_release_file,
+};
+
+static int __init parse_pks_test_options(char *str)
+{
+	run_on_boot = true;
+
+	return 0;
+}
+early_param("pks-test-on-boot", parse_pks_test_options);
+
+static int __init pks_test_init(void)
+{
+	if (cpu_feature_enabled(X86_FEATURE_PKS)) {
+		if (run_on_boot)
+			run_all();
+
+		pks_test_dentry = debugfs_create_file("run_pks", 0600, arch_debugfs_dir,
+						      NULL, &fops_init_pks);
+	}
+
+	return 0;
+}
+late_initcall(pks_test_init);
+
+static void __exit pks_test_exit(void)
+{
+	debugfs_remove(pks_test_dentry);
+	pr_info("test exit\n");
+}
+module_exit(pks_test_exit);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index d2796ea98c5a..3572dfb25c0a 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -13,7 +13,8 @@ CAN_BUILD_WITH_NOPIE := $(shell ./check_cc.sh $(CC) trivial_program.c -no-pie)
 TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap_vdso \
 			check_initial_reg_state sigreturn iopl ioperm \
 			test_vdso test_vsyscall mov_ss_trap \
-			syscall_arg_fault
+			syscall_arg_fault test_pks
+
 TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
diff --git a/tools/testing/selftests/x86/test_pks.c b/tools/testing/selftests/x86/test_pks.c
new file mode 100644
index 000000000000..8037a2a9ff5f
--- /dev/null
+++ b/tools/testing/selftests/x86/test_pks.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <assert.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main(void)
+{
+	cpu_set_t cpuset;
+	char result[32];
+	pid_t pid;
+	int fd;
+
+	CPU_ZERO(&cpuset);
+	CPU_SET(0, &cpuset);
+	/* Two processes run on CPU 0 so that they go through context switch. */
+	sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset);
+
+	pid = fork();
+	if (pid == 0) {
+		fd = open("/sys/kernel/debug/x86/run_pks", O_RDWR);
+		if (fd < 0) {
+			printf("cannot open file\n");
+			return -1;
+		}
+
+		/* Allocate test_pkey1 and run test. */
+		write(fd, "0", 1);
+
+		/* Arm for context switch test */
+		write(fd, "1", 1);
+
+		/* Context switch out... */
+		sleep(4);
+
+		/* Check msr restored */
+		write(fd, "2", 1);
+	} else {
+		sleep(2);
+
+		fd = open("/sys/kernel/debug/x86/run_pks", O_RDWR);
+		if (fd < 0) {
+			printf("cannot open file\n");
+			return -1;
+		}
+
+		/* run test with alternate pkey */
+		write(fd, "0", 1);
+	}
+
+	read(fd, result, 10);
+	printf("#PF, context switch, pkey allocation and free tests: %s\n",
+	       result);
+
+	close(fd);
+
+	return 0;
+}
