19 files changed, 228 insertions, 57 deletions

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index d57112a276f5..c23dbf8bebee 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -354,8 +354,8 @@ static void __init free_highpages(void)
 	/* set highmem page free */
 	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 				&range_start, &range_end, NULL) {
-		unsigned long start = PHYS_PFN(range_start);
-		unsigned long end = PHYS_PFN(range_end);
+		unsigned long start = PFN_UP(range_start);
+		unsigned long end = PFN_DOWN(range_end);
 
 		/* Ignore complete lowmem entries */
 		if (end <= max_low)
diff --git a/arch/s390/configs/debug_defconfig b/arch/s390/configs/debug_defconfig
index 0784bf3caf43..a4d3c578fbd8 100644
--- a/arch/s390/configs/debug_defconfig
+++ b/arch/s390/configs/debug_defconfig
@@ -93,9 +93,10 @@ CONFIG_CLEANCACHE=y
 CONFIG_FRONTSWAP=y
 CONFIG_CMA_DEBUG=y
 CONFIG_CMA_DEBUGFS=y
+CONFIG_CMA_AREAS=7
 CONFIG_MEM_SOFT_DIRTY=y
 CONFIG_ZSWAP=y
-CONFIG_ZSMALLOC=m
+CONFIG_ZSMALLOC=y
 CONFIG_ZSMALLOC_STAT=y
 CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
 CONFIG_IDLE_PAGE_TRACKING=y
@@ -378,7 +379,6 @@ CONFIG_NETLINK_DIAG=m
 CONFIG_CGROUP_NET_PRIO=y
 CONFIG_BPF_JIT=y
 CONFIG_NET_PKTGEN=m
-# CONFIG_NET_DROP_MONITOR is not set
 CONFIG_PCI=y
 # CONFIG_PCIEASPM is not set
 CONFIG_PCI_DEBUG=y
@@ -386,7 +386,7 @@ CONFIG_HOTPLUG_PCI=y
 CONFIG_HOTPLUG_PCI_S390=y
 CONFIG_DEVTMPFS=y
 CONFIG_CONNECTOR=y
-CONFIG_ZRAM=m
+CONFIG_ZRAM=y
 CONFIG_BLK_DEV_LOOP=m
 CONFIG_BLK_DEV_CRYPTOLOOP=m
 CONFIG_BLK_DEV_DRBD=m
@@ -689,6 +689,7 @@ CONFIG_CRYPTO_TEST=m
 CONFIG_CRYPTO_DH=m
 CONFIG_CRYPTO_ECDH=m
 CONFIG_CRYPTO_ECRDSA=m
+CONFIG_CRYPTO_SM2=m
 CONFIG_CRYPTO_CURVE25519=m
 CONFIG_CRYPTO_GCM=y
 CONFIG_CRYPTO_CHACHA20POLY1305=m
@@ -709,7 +710,6 @@ CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_RMD256=m
 CONFIG_CRYPTO_RMD320=m
 CONFIG_CRYPTO_SHA3=m
-CONFIG_CRYPTO_SM3=m
 CONFIG_CRYPTO_TGR192=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_AES_TI=m
@@ -753,6 +753,7 @@ CONFIG_CRYPTO_DES_S390=m
 CONFIG_CRYPTO_AES_S390=m
 CONFIG_CRYPTO_GHASH_S390=m
 CONFIG_CRYPTO_CRC32_S390=y
+CONFIG_CRYPTO_DEV_VIRTIO=m
 CONFIG_CORDIC=m
 CONFIG_CRC32_SELFTEST=y
 CONFIG_CRC4=m
@@ -829,6 +830,7 @@ CONFIG_NETDEV_NOTIFIER_ERROR_INJECT=m
 CONFIG_FAULT_INJECTION=y
 CONFIG_FAILSLAB=y
 CONFIG_FAIL_PAGE_ALLOC=y
+CONFIG_FAULT_INJECTION_USERCOPY=y
 CONFIG_FAIL_MAKE_REQUEST=y
 CONFIG_FAIL_IO_TIMEOUT=y
 CONFIG_FAIL_FUTEX=y
diff --git a/arch/s390/configs/defconfig b/arch/s390/configs/defconfig
index 905bc8c4cfaf..17d5df2c1eff 100644
--- a/arch/s390/configs/defconfig
+++ b/arch/s390/configs/defconfig
@@ -87,9 +87,10 @@ CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_CLEANCACHE=y
 CONFIG_FRONTSWAP=y
+CONFIG_CMA_AREAS=7
 CONFIG_MEM_SOFT_DIRTY=y
 CONFIG_ZSWAP=y
-CONFIG_ZSMALLOC=m
+CONFIG_ZSMALLOC=y
 CONFIG_ZSMALLOC_STAT=y
 CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
 CONFIG_IDLE_PAGE_TRACKING=y
@@ -371,7 +372,6 @@ CONFIG_NETLINK_DIAG=m
 CONFIG_CGROUP_NET_PRIO=y
 CONFIG_BPF_JIT=y
 CONFIG_NET_PKTGEN=m
-# CONFIG_NET_DROP_MONITOR is not set
 CONFIG_PCI=y
 # CONFIG_PCIEASPM is not set
 CONFIG_HOTPLUG_PCI=y
@@ -379,7 +379,7 @@ CONFIG_HOTPLUG_PCI_S390=y
 CONFIG_UEVENT_HELPER=y
 CONFIG_DEVTMPFS=y
 CONFIG_CONNECTOR=y
-CONFIG_ZRAM=m
+CONFIG_ZRAM=y
 CONFIG_BLK_DEV_LOOP=m
 CONFIG_BLK_DEV_CRYPTOLOOP=m
 CONFIG_BLK_DEV_DRBD=m
@@ -680,6 +680,7 @@ CONFIG_CRYPTO_TEST=m
 CONFIG_CRYPTO_DH=m
 CONFIG_CRYPTO_ECDH=m
 CONFIG_CRYPTO_ECRDSA=m
+CONFIG_CRYPTO_SM2=m
 CONFIG_CRYPTO_CURVE25519=m
 CONFIG_CRYPTO_GCM=y
 CONFIG_CRYPTO_CHACHA20POLY1305=m
@@ -701,7 +702,6 @@ CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_RMD256=m
 CONFIG_CRYPTO_RMD320=m
 CONFIG_CRYPTO_SHA3=m
-CONFIG_CRYPTO_SM3=m
 CONFIG_CRYPTO_TGR192=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_AES_TI=m
@@ -745,6 +745,7 @@ CONFIG_CRYPTO_DES_S390=m
 CONFIG_CRYPTO_AES_S390=m
 CONFIG_CRYPTO_GHASH_S390=m
 CONFIG_CRYPTO_CRC32_S390=y
+CONFIG_CRYPTO_DEV_VIRTIO=m
 CONFIG_CORDIC=m
 CONFIG_PRIME_NUMBERS=m
 CONFIG_CRC4=m
diff --git a/arch/s390/configs/zfcpdump_defconfig b/arch/s390/configs/zfcpdump_defconfig
index 8f67c55625f9..a302630341ef 100644
--- a/arch/s390/configs/zfcpdump_defconfig
+++ b/arch/s390/configs/zfcpdump_defconfig
@@ -17,11 +17,11 @@ CONFIG_HZ_100=y
 # CONFIG_CHSC_SCH is not set
 # CONFIG_SCM_BUS is not set
 CONFIG_CRASH_DUMP=y
-# CONFIG_SECCOMP is not set
 # CONFIG_PFAULT is not set
 # CONFIG_S390_HYPFS_FS is not set
 # CONFIG_VIRTUALIZATION is not set
 # CONFIG_S390_GUEST is not set
+# CONFIG_SECCOMP is not set
 CONFIG_PARTITION_ADVANCED=y
 CONFIG_IBM_PARTITION=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 6b8d8c69b1a1..b5dbae78969b 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -692,16 +692,6 @@ static inline int pud_large(pud_t pud)
 	return !!(pud_val(pud) & _REGION3_ENTRY_LARGE);
 }
 
-static inline unsigned long pud_pfn(pud_t pud)
-{
-	unsigned long origin_mask;
-
-	origin_mask = _REGION_ENTRY_ORIGIN;
-	if (pud_large(pud))
-		origin_mask = _REGION3_ENTRY_ORIGIN_LARGE;
-	return (pud_val(pud) & origin_mask) >> PAGE_SHIFT;
-}
-
 #define pmd_leaf	pmd_large
 static inline int pmd_large(pmd_t pmd)
 {
@@ -747,16 +737,6 @@ static inline int pmd_none(pmd_t pmd)
 	return pmd_val(pmd) == _SEGMENT_ENTRY_EMPTY;
 }
 
-static inline unsigned long pmd_pfn(pmd_t pmd)
-{
-	unsigned long origin_mask;
-
-	origin_mask = _SEGMENT_ENTRY_ORIGIN;
-	if (pmd_large(pmd))
-		origin_mask = _SEGMENT_ENTRY_ORIGIN_LARGE;
-	return (pmd_val(pmd) & origin_mask) >> PAGE_SHIFT;
-}
-
 #define pmd_write pmd_write
 static inline int pmd_write(pmd_t pmd)
 {
@@ -1238,11 +1218,39 @@ static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)
 #define pud_index(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 #define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 
-#define pmd_deref(pmd) (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN)
-#define pud_deref(pud) (pud_val(pud) & _REGION_ENTRY_ORIGIN)
 #define p4d_deref(pud) (p4d_val(pud) & _REGION_ENTRY_ORIGIN)
 #define pgd_deref(pgd) (pgd_val(pgd) & _REGION_ENTRY_ORIGIN)
 
+static inline unsigned long pmd_deref(pmd_t pmd)
+{
+	unsigned long origin_mask;
+
+	origin_mask = _SEGMENT_ENTRY_ORIGIN;
+	if (pmd_large(pmd))
+		origin_mask = _SEGMENT_ENTRY_ORIGIN_LARGE;
+	return pmd_val(pmd) & origin_mask;
+}
+
+static inline unsigned long pmd_pfn(pmd_t pmd)
+{
+	return pmd_deref(pmd) >> PAGE_SHIFT;
+}
+
+static inline unsigned long pud_deref(pud_t pud)
+{
+	unsigned long origin_mask;
+
+	origin_mask = _REGION_ENTRY_ORIGIN;
+	if (pud_large(pud))
+		origin_mask = _REGION3_ENTRY_ORIGIN_LARGE;
+	return pud_val(pud) & origin_mask;
+}
+
+static inline unsigned long pud_pfn(pud_t pud)
+{
+	return pud_deref(pud) >> PAGE_SHIFT;
+}
+
 /*
  * The pgd_offset function *always* adds the index for the top-level
  * region/segment table. This is done to get a sequence like the
diff --git a/arch/s390/include/asm/vdso/vdso.h b/arch/s390/include/asm/vdso/vdso.h
deleted file mode 100644
index e69de29bb2d1..000000000000
--- a/arch/s390/include/asm/vdso/vdso.h
+++ /dev/null
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index ece58f2217cb..2012c1cf0853 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -61,14 +61,6 @@ int main(void)
 	BLANK();
 	OFFSET(__VDSO_GETCPU_VAL, vdso_per_cpu_data, getcpu_val);
 	BLANK();
-	/* constants used by the vdso */
-	DEFINE(__CLOCK_REALTIME, CLOCK_REALTIME);
-	DEFINE(__CLOCK_MONOTONIC, CLOCK_MONOTONIC);
-	DEFINE(__CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE);
-	DEFINE(__CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE);
-	DEFINE(__CLOCK_THREAD_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID);
-	DEFINE(__CLOCK_COARSE_RES, LOW_RES_NSEC);
-	BLANK();
 	/* idle data offsets */
 	OFFSET(__CLOCK_IDLE_ENTER, s390_idle_data, clock_idle_enter);
 	OFFSET(__CLOCK_IDLE_EXIT, s390_idle_data, clock_idle_exit);
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index ebfe86d097f0..390d97daa2b3 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -855,13 +855,14 @@ void __init smp_detect_cpus(void)
 
 static void smp_init_secondary(void)
 {
-	int cpu = smp_processor_id();
+	int cpu = raw_smp_processor_id();
 
 	S390_lowcore.last_update_clock = get_tod_clock();
 	restore_access_regs(S390_lowcore.access_regs_save_area);
 	set_cpu_flag(CIF_ASCE_PRIMARY);
 	set_cpu_flag(CIF_ASCE_SECONDARY);
 	cpu_init();
+	rcu_cpu_starting(cpu);
 	preempt_disable();
 	init_cpu_timer();
 	vtime_init();
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index d33f21545dfd..9a6bae503fe6 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -101,6 +101,10 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 		if (ret)
 			break;
 
+		/* the PCI function will be scanned once function 0 appears */
+		if (!zdev->zbus->bus)
+			break;
+
 		pdev = pci_scan_single_device(zdev->zbus->bus, zdev->devfn);
 		if (!pdev)
 			break;
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index a5e5db6ada3c..39b2eded7bc2 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -164,6 +164,7 @@ void initialize_identity_maps(void *rmode)
 	add_identity_map(cmdline, cmdline + COMMAND_LINE_SIZE);
 
 	/* Load the new page-table. */
+	sev_verify_cbit(top_level_pgt);
 	write_cr3(top_level_pgt);
 }
 
diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
index dd07e7b41b11..aa561795efd1 100644
--- a/arch/x86/boot/compressed/mem_encrypt.S
+++ b/arch/x86/boot/compressed/mem_encrypt.S
@@ -68,6 +68,9 @@ SYM_FUNC_START(get_sev_encryption_bit)
 SYM_FUNC_END(get_sev_encryption_bit)
 
 	.code64
+
+#include "../../kernel/sev_verify_cbit.S"
+
 SYM_FUNC_START(set_sev_encryption_mask)
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 	push	%rbp
@@ -81,6 +84,19 @@ SYM_FUNC_START(set_sev_encryption_mask)
 
 	bts	%rax, sme_me_mask(%rip)	/* Create the encryption mask */
 
+	/*
+	 * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in
+	 * get_sev_encryption_bit() because this function is 32-bit code and
+	 * shared between 64-bit and 32-bit boot path.
+	 */
+	movl	$MSR_AMD64_SEV, %ecx	/* Read the SEV MSR */
+	rdmsr
+
+	/* Store MSR value in sev_status */
+	shlq	$32, %rdx
+	orq	%rdx, %rax
+	movq	%rax, sev_status(%rip)
+
 .Lno_sev_mask:
 	movq	%rbp, %rsp		/* Restore original stack pointer */
 
@@ -96,5 +112,7 @@ SYM_FUNC_END(set_sev_encryption_mask)
 
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 	.balign	8
-SYM_DATA(sme_me_mask, .quad 0)
+SYM_DATA(sme_me_mask,		.quad 0)
+SYM_DATA(sev_status,		.quad 0)
+SYM_DATA(sev_check_data,	.quad 0)
 #endif
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 6d31f1b4c4d1..d9a631c5973c 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -159,4 +159,6 @@ void boot_page_fault(void);
 void boot_stage1_vc(void);
 void boot_stage2_vc(void);
 
+unsigned long sev_verify_cbit(unsigned long cr3);
+
 #endif /* BOOT_COMPRESSED_MISC_H */
diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index 40e0e322161d..284e73661a18 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -273,11 +273,15 @@ void __init hv_apic_init(void)
 		pr_info("Hyper-V: Using enlightened APIC (%s mode)",
 			x2apic_enabled() ? "x2apic" : "xapic");
 		/*
-		 * With x2apic, architectural x2apic MSRs are equivalent to the
-		 * respective synthetic MSRs, so there's no need to override
-		 * the apic accessors.  The only exception is
-		 * hv_apic_eoi_write, because it benefits from lazy EOI when
-		 * available, but it works for both xapic and x2apic modes.
+		 * When in x2apic mode, don't use the Hyper-V specific APIC
+		 * accessors since the field layout in the ICR register is
+		 * different in x2apic mode. Furthermore, the architectural
+		 * x2apic MSRs function just as well as the Hyper-V
+		 * synthetic APIC MSRs, so there's no benefit in having
+		 * separate Hyper-V accessors for x2apic mode. The only
+		 * exception is hv_apic_eoi_write, because it benefits from
+		 * lazy EOI when available, but the same accessor works for
+		 * both xapic and x2apic because the field layout is the same.
 		 */
 		apic_set_eoi_write(hv_apic_eoi_write);
 		if (!x2apic_enabled()) {
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 7eb2a1c87969..3c417734790f 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -161,6 +161,21 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
 
 	/* Setup early boot stage 4-/5-level pagetables. */
 	addq	phys_base(%rip), %rax
+
+	/*
+	 * For SEV guests: Verify that the C-bit is correct. A malicious
+	 * hypervisor could lie about the C-bit position to perform a ROP
+	 * attack on the guest by writing to the unencrypted stack and wait for
+	 * the next RET instruction.
+	 * %rsi carries pointer to realmode data and is callee-clobbered. Save
+	 * and restore it.
+	 */
+	pushq	%rsi
+	movq	%rax, %rdi
+	call	sev_verify_cbit
+	popq	%rsi
+
+	/* Switch to new page-table */
 	movq	%rax, %cr3
 
 	/* Ensure I am executing from virtual addresses */
@@ -279,6 +294,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
 SYM_CODE_END(secondary_startup_64)
 
 #include "verify_cpu.S"
+#include "sev_verify_cbit.S"
 
 #ifdef CONFIG_HOTPLUG_CPU
 /*
diff --git a/arch/x86/kernel/sev-es-shared.c b/arch/x86/kernel/sev-es-shared.c
index 5f83ccaab877..7d04b356d44d 100644
--- a/arch/x86/kernel/sev-es-shared.c
+++ b/arch/x86/kernel/sev-es-shared.c
@@ -178,6 +178,32 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 		goto fail;
 	regs->dx = val >> 32;
 
+	/*
+	 * This is a VC handler and the #VC is only raised when SEV-ES is
+	 * active, which means SEV must be active too. Do sanity checks on the
+	 * CPUID results to make sure the hypervisor does not trick the kernel
+	 * into the no-sev path. This could map sensitive data unencrypted and
+	 * make it accessible to the hypervisor.
+	 *
+	 * In particular, check for:
+	 *	- Hypervisor CPUID bit
+	 *	- Availability of CPUID leaf 0x8000001f
+	 *	- SEV CPUID bit.
+	 *
+	 * The hypervisor might still report the wrong C-bit position, but this
+	 * can't be checked here.
+	 */
+
+	if ((fn == 1 && !(regs->cx & BIT(31))))
+		/* Hypervisor bit */
+		goto fail;
+	else if (fn == 0x80000000 && (regs->ax < 0x8000001f))
+		/* SEV leaf check */
+		goto fail;
+	else if ((fn == 0x8000001f && !(regs->ax & BIT(1))))
+		/* SEV bit */
+		goto fail;
+
 	/* Skip over the CPUID two-byte opcode */
 	regs->ip += 2;
 
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 4a96726fbaf8..0bd1a0fc587e 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -374,8 +374,8 @@ fault:
 	return ES_EXCEPTION;
 }
 
-static bool vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
-				 unsigned long vaddr, phys_addr_t *paddr)
+static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
+					   unsigned long vaddr, phys_addr_t *paddr)
 {
 	unsigned long va = (unsigned long)vaddr;
 	unsigned int level;
@@ -394,15 +394,19 @@ static bool vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
 		if (user_mode(ctxt->regs))
 			ctxt->fi.error_code |= X86_PF_USER;
 
-		return false;
+		return ES_EXCEPTION;
 	}
 
+	if (WARN_ON_ONCE(pte_val(*pte) & _PAGE_ENC))
+		/* Emulated MMIO to/from encrypted memory not supported */
+		return ES_UNSUPPORTED;
+
 	pa = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
 	pa |= va & ~page_level_mask(level);
 
 	*paddr = pa;
 
-	return true;
+	return ES_OK;
 }
 
 /* Include code shared with pre-decompression boot stage */
@@ -731,6 +735,7 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
 {
 	u64 exit_code, exit_info_1, exit_info_2;
 	unsigned long ghcb_pa = __pa(ghcb);
+	enum es_result res;
 	phys_addr_t paddr;
 	void __user *ref;
 
@@ -740,11 +745,12 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
 
 	exit_code = read ? SVM_VMGEXIT_MMIO_READ : SVM_VMGEXIT_MMIO_WRITE;
 
-	if (!vc_slow_virt_to_phys(ghcb, ctxt, (unsigned long)ref, &paddr)) {
-		if (!read)
+	res = vc_slow_virt_to_phys(ghcb, ctxt, (unsigned long)ref, &paddr);
+	if (res != ES_OK) {
+		if (res == ES_EXCEPTION && !read)
 			ctxt->fi.error_code |= X86_PF_WRITE;
 
-		return ES_EXCEPTION;
+		return res;
 	}
 
 	exit_info_1 = paddr;
diff --git a/arch/x86/kernel/sev_verify_cbit.S b/arch/x86/kernel/sev_verify_cbit.S
new file mode 100644
index 000000000000..ee04941a6546
--- /dev/null
+++ b/arch/x86/kernel/sev_verify_cbit.S
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *	sev_verify_cbit.S - Code for verification of the C-bit position reported
+ *			    by the Hypervisor when running with SEV enabled.
+ *
+ *	Copyright (c) 2020  Joerg Roedel (jroedel@suse.de)
+ *
+ * sev_verify_cbit() is called before switching to a new long-mode page-table
+ * at boot.
+ *
+ * Verify that the C-bit position is correct by writing a random value to
+ * an encrypted memory location while on the current page-table. Then it
+ * switches to the new page-table to verify the memory content is still the
+ * same. After that it switches back to the current page-table and when the
+ * check succeeded it returns. If the check failed the code invalidates the
+ * stack pointer and goes into a hlt loop. The stack-pointer is invalidated to
+ * make sure no interrupt or exception can get the CPU out of the hlt loop.
+ *
+ * New page-table pointer is expected in %rdi (first parameter)
+ *
+ */
+SYM_FUNC_START(sev_verify_cbit)
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	/* First check if a C-bit was detected */
+	movq	sme_me_mask(%rip), %rsi
+	testq	%rsi, %rsi
+	jz	3f
+
+	/* sme_me_mask != 0 could mean SME or SEV - Check also for SEV */
+	movq	sev_status(%rip), %rsi
+	testq	%rsi, %rsi
+	jz	3f
+
+	/* Save CR4 in %rsi */
+	movq	%cr4, %rsi
+
+	/* Disable Global Pages */
+	movq	%rsi, %rdx
+	andq	$(~X86_CR4_PGE), %rdx
+	movq	%rdx, %cr4
+
+	/*
+	 * Verified that running under SEV - now get a random value using
+	 * RDRAND. This instruction is mandatory when running as an SEV guest.
+	 *
+	 * Don't bail out of the loop if RDRAND returns errors. It is better to
+	 * prevent forward progress than to work with a non-random value here.
+	 */
+1:	rdrand	%rdx
+	jnc	1b
+
+	/* Store value to memory and keep it in %rdx */
+	movq	%rdx, sev_check_data(%rip)
+
+	/* Backup current %cr3 value to restore it later */
+	movq	%cr3, %rcx
+
+	/* Switch to new %cr3 - This might unmap the stack */
+	movq	%rdi, %cr3
+
+	/*
+	 * Compare value in %rdx with memory location. If C-bit is incorrect
+	 * this would read the encrypted data and make the check fail.
+	 */
+	cmpq	%rdx, sev_check_data(%rip)
+
+	/* Restore old %cr3 */
+	movq	%rcx, %cr3
+
+	/* Restore previous CR4 */
+	movq	%rsi, %cr4
+
+	/* Check CMPQ result */
+	je	3f
+
+	/*
+	 * The check failed, prevent any forward progress to prevent ROP
+	 * attacks, invalidate the stack and go into a hlt loop.
+	 */
+	xorq	%rsp, %rsp
+	subq	$0x1000, %rsp
+2:	hlt
+	jmp 2b
+3:
+#endif
+	/* Return page-table pointer */
+	movq	%rdi, %rax
+	ret
+SYM_FUNC_END(sev_verify_cbit)
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index efbb3de472df..bc0833713be9 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -39,6 +39,7 @@
  */
 u64 sme_me_mask __section(".data") = 0;
 u64 sev_status __section(".data") = 0;
+u64 sev_check_data __section(".data") = 0;
 EXPORT_SYMBOL(sme_me_mask);
 DEFINE_STATIC_KEY_FALSE(sev_enable_key);
 EXPORT_SYMBOL_GPL(sev_enable_key);
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index c6fc83efee0c..8731b7ad9308 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -89,8 +89,8 @@ static void __init free_highpages(void)
 	/* set highmem page free */
 	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
 				&range_start, &range_end, NULL) {
-		unsigned long start = PHYS_PFN(range_start);
-		unsigned long end = PHYS_PFN(range_end);
+		unsigned long start = PFN_UP(range_start);
+		unsigned long end = PFN_DOWN(range_end);
 
 		/* Ignore complete lowmem entries */
 		if (end <= max_low)