Merge tag 'x86_sev_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:
 "The accumulated pile of x86/sev generalizations and cleanups:

   - Share the SEV string unrolling logic with TDX as TDX guests need it
     too

   - Cleanups and generalzation of code shared by SEV and TDX"

* tag 'x86_sev_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Move common memory encryption code to mem_encrypt.c
  x86/sev: Rename mem_encrypt.c to mem_encrypt_amd.c
  x86/sev: Use CC_ATTR attribute to generalize string I/O unroll
  x86/sev: Remove do_early_exception() forward declarations
  x86/head64: Carve out the guest encryption postprocessing into a helper
  x86/sev: Get rid of excessive use of defines
  x86/sev: Shorten GHCB terminate macro names

arch/x86/Kconfig

@@ -1523,16 +1523,20 @@ config X86_CPA_STATISTICS
 	  helps to determine the effectiveness of preserving large and huge
 	  page mappings when mapping protections are changed.
 
+config X86_MEM_ENCRYPT
+	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
+	select DYNAMIC_PHYSICAL_MASK
+	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+	def_bool n
+
 config AMD_MEM_ENCRYPT
 	bool "AMD Secure Memory Encryption (SME) support"
 	depends on X86_64 && CPU_SUP_AMD
 	select DMA_COHERENT_POOL
-	select DYNAMIC_PHYSICAL_MASK
 	select ARCH_USE_MEMREMAP_PROT
-	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 	select INSTRUCTION_DECODER
-	select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
 	select ARCH_HAS_CC_PLATFORM
+	select X86_MEM_ENCRYPT
 	help
 	  Say yes to enable support for the encryption of system memory.
 	  This requires an AMD processor that supports Secure Memory

arch/x86/boot/compressed/sev.c

@@ -122,7 +122,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 static bool early_setup_sev_es(void)
 {
 	if (!sev_es_negotiate_protocol())
-		sev_es_terminate(GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED);
+		sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);
 
 	if (set_page_decrypted((unsigned long)&boot_ghcb_page))
 		return false;
@@ -175,7 +175,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	enum es_result result;
 
 	if (!boot_ghcb && !early_setup_sev_es())
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 	result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,5 +202,5 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	if (result == ES_OK)
 		vc_finish_insn(&ctxt);
 	else if (result != ES_RETRY)
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 }

arch/x86/include/asm/io.h

@@ -40,6 +40,7 @@
 
 #include <linux/string.h>
 #include <linux/compiler.h>
+#include <linux/cc_platform.h>
 #include <asm/page.h>
 #include <asm/early_ioremap.h>
 #include <asm/pgtable_types.h>
@@ -256,21 +257,6 @@ static inline void slow_down_io(void)
 
 #endif
 
-#ifdef CONFIG_AMD_MEM_ENCRYPT
-#include <linux/jump_label.h>
-
-extern struct static_key_false sev_enable_key;
-static inline bool sev_key_active(void)
-{
-	return static_branch_unlikely(&sev_enable_key);
-}
-
-#else /* !CONFIG_AMD_MEM_ENCRYPT */
-
-static inline bool sev_key_active(void) { return false; }
-
-#endif /* CONFIG_AMD_MEM_ENCRYPT */
-
 #define BUILDIO(bwl, bw, type)						\
 static inline void out##bwl(unsigned type value, int port)		\
 {									\
@@ -301,7 +287,7 @@ static inline unsigned type in##bwl##_p(int port)			\
 									\
 static inline void outs##bwl(int port, const void *addr, unsigned long count) \
 {									\
-	if (sev_key_active()) {						\
+	if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) {		\
 		unsigned type *value = (unsigned type *)addr;		\
 		while (count) {						\
 			out##bwl(*value, port);				\
@@ -317,7 +303,7 @@ static inline void outs##bwl(int port, const void *addr, unsigned long count) \
 									\
 static inline void ins##bwl(int port, void *addr, unsigned long count)	\
 {									\
-	if (sev_key_active()) {						\
+	if (cc_platform_has(CC_ATTR_GUEST_UNROLL_STRING_IO)) {		\
 		unsigned type *value = (unsigned type *)addr;		\
 		while (count) {						\
 			*value = in##bwl(port);				\

arch/x86/include/asm/sev-common.h

@@ -18,20 +18,19 @@
 /* SEV Information Request/Response */
 #define GHCB_MSR_SEV_INFO_RESP		0x001
 #define GHCB_MSR_SEV_INFO_REQ		0x002
-#define GHCB_MSR_VER_MAX_POS		48
-#define GHCB_MSR_VER_MAX_MASK		0xffff
-#define GHCB_MSR_VER_MIN_POS		32
-#define GHCB_MSR_VER_MIN_MASK		0xffff
-#define GHCB_MSR_CBIT_POS		24
-#define GHCB_MSR_CBIT_MASK		0xff
+
 #define GHCB_MSR_SEV_INFO(_max, _min, _cbit)	\
-	((((_max) & GHCB_MSR_VER_MAX_MASK) << GHCB_MSR_VER_MAX_POS) |	\
-	 (((_min) & GHCB_MSR_VER_MIN_MASK) << GHCB_MSR_VER_MIN_POS) |	\
-	 (((_cbit) & GHCB_MSR_CBIT_MASK) << GHCB_MSR_CBIT_POS) |	\
+	/* GHCBData[63:48] */			\
+	((((_max) & 0xffff) << 48) |		\
+	 /* GHCBData[47:32] */			\
+	 (((_min) & 0xffff) << 32) |		\
+	 /* GHCBData[31:24] */			\
+	 (((_cbit) & 0xff)  << 24) |		\
 	 GHCB_MSR_SEV_INFO_RESP)
+
 #define GHCB_MSR_INFO(v)		((v) & 0xfffUL)
-#define GHCB_MSR_PROTO_MAX(v)		(((v) >> GHCB_MSR_VER_MAX_POS) & GHCB_MSR_VER_MAX_MASK)
-#define GHCB_MSR_PROTO_MIN(v)		(((v) >> GHCB_MSR_VER_MIN_POS) & GHCB_MSR_VER_MIN_MASK)
+#define GHCB_MSR_PROTO_MAX(v)		(((v) >> 48) & 0xffff)
+#define GHCB_MSR_PROTO_MIN(v)		(((v) >> 32) & 0xffff)
 
 /* CPUID Request/Response */
 #define GHCB_MSR_CPUID_REQ		0x004
@@ -47,9 +46,12 @@
 #define GHCB_CPUID_REQ_ECX		2
 #define GHCB_CPUID_REQ_EDX		3
 #define GHCB_CPUID_REQ(fn, reg)				\
+	/* GHCBData[11:0] */				\
 	(GHCB_MSR_CPUID_REQ |				\
-		(((unsigned long)reg & GHCB_MSR_CPUID_REG_MASK) << GHCB_MSR_CPUID_REG_POS) | \
-		(((unsigned long)fn) << GHCB_MSR_CPUID_FUNC_POS))
+	/* GHCBData[31:12] */				\
+	(((unsigned long)(reg) & 0x3) << 30) |		\
+	/* GHCBData[63:32] */				\
+	(((unsigned long)fn) << 32))
 
 /* AP Reset Hold */
 #define GHCB_MSR_AP_RESET_HOLD_REQ	0x006
@@ -64,12 +66,15 @@
 #define GHCB_MSR_TERM_REASON_SET_MASK	0xf
 #define GHCB_MSR_TERM_REASON_POS	16
 #define GHCB_MSR_TERM_REASON_MASK	0xff
+
 #define GHCB_SEV_TERM_REASON(reason_set, reason_val)	\
-	(((((u64)reason_set) &  GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \
-	((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS))
+	/* GHCBData[15:12] */				\
+	(((((u64)reason_set) &  0xf) << 12) |		\
+	 /* GHCBData[23:16] */				\
+	((((u64)reason_val) & 0xff) << 16))
 
-#define GHCB_SEV_ES_REASON_GENERAL_REQUEST	0
-#define GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED	1
+#define GHCB_SEV_ES_GEN_REQ		0
+#define GHCB_SEV_ES_PROT_UNSUPPORTED	1
 
 #define GHCB_RESP_CODE(v)		((v) & GHCB_MSR_INFO_MASK)
 

arch/x86/kernel/cc_platform.c

@@ -50,6 +50,14 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 	case CC_ATTR_GUEST_STATE_ENCRYPT:
 		return sev_status & MSR_AMD64_SEV_ES_ENABLED;
 
+	/*
+	 * With SEV, the rep string I/O instructions need to be unrolled
+	 * but SEV-ES supports them through the #VC handler.
+	 */
+	case CC_ATTR_GUEST_UNROLL_STRING_IO:
+		return (sev_status & MSR_AMD64_SEV_ENABLED) &&
+			!(sev_status & MSR_AMD64_SEV_ES_ENABLED);
+
 	default:
 		return false;
 	}

arch/x86/kernel/head64.c

@@ -126,6 +126,36 @@ static bool __head check_la57_support(unsigned long physaddr)
 }
 #endif
 
+static unsigned long sme_postprocess_startup(struct boot_params *bp, pmdval_t *pmd)
+{
+	unsigned long vaddr, vaddr_end;
+	int i;
+
+	/* Encrypt the kernel and related (if SME is active) */
+	sme_encrypt_kernel(bp);
+
+	/*
+	 * Clear the memory encryption mask from the .bss..decrypted section.
+	 * The bss section will be memset to zero later in the initialization so
+	 * there is no need to zero it after changing the memory encryption
+	 * attribute.
+	 */
+	if (sme_get_me_mask()) {
+		vaddr = (unsigned long)__start_bss_decrypted;
+		vaddr_end = (unsigned long)__end_bss_decrypted;
+		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
+			i = pmd_index(vaddr);
+			pmd[i] -= sme_get_me_mask();
+		}
+	}
+
+	/*
+	 * Return the SME encryption mask (if SME is active) to be used as a
+	 * modifier for the initial pgdir entry programmed into CR3.
+	 */
+	return sme_get_me_mask();
+}
+
 /* Code in __startup_64() can be relocated during execution, but the compiler
  * doesn't have to generate PC-relative relocations when accessing globals from
  * that function. Clang actually does not generate them, which leads to
@@ -135,7 +165,6 @@ static bool __head check_la57_support(unsigned long physaddr)
 unsigned long __head __startup_64(unsigned long physaddr,
 				  struct boot_params *bp)
 {
-	unsigned long vaddr, vaddr_end;
 	unsigned long load_delta, *p;
 	unsigned long pgtable_flags;
 	pgdval_t *pgd;
@@ -276,34 +305,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	 */
 	*fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
 
-	/* Encrypt the kernel and related (if SME is active) */
-	sme_encrypt_kernel(bp);
-
-	/*
-	 * Clear the memory encryption mask from the .bss..decrypted section.
-	 * The bss section will be memset to zero later in the initialization so
-	 * there is no need to zero it after changing the memory encryption
-	 * attribute.
-	 *
-	 * This is early code, use an open coded check for SME instead of
-	 * using cc_platform_has(). This eliminates worries about removing
-	 * instrumentation or checking boot_cpu_data in the cc_platform_has()
-	 * function.
-	 */
-	if (sme_get_me_mask()) {
-		vaddr = (unsigned long)__start_bss_decrypted;
-		vaddr_end = (unsigned long)__end_bss_decrypted;
-		for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
-			i = pmd_index(vaddr);
-			pmd[i] -= sme_get_me_mask();
-		}
-	}
-
-	/*
-	 * Return the SME encryption mask (if SME is active) to be used as a
-	 * modifier for the initial pgdir entry programmed into CR3.
-	 */
-	return sme_get_me_mask();
+	return sme_postprocess_startup(bp, pmd);
 }
 
 unsigned long __startup_secondary_64(void)

arch/x86/kernel/sev-shared.c

@@ -221,7 +221,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 
 fail:
 	/* Terminate the guest */
-	sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+	sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,

arch/x86/kernel/sev.c

@@ -26,6 +26,7 @@
 #include <asm/fpu/xcr.h>
 #include <asm/processor.h>
 #include <asm/realmode.h>
+#include <asm/setup.h>
 #include <asm/traps.h>
 #include <asm/svm.h>
 #include <asm/smp.h>
@@ -86,9 +87,6 @@ struct ghcb_state {
 static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
 DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
 
-/* Needed in vc_early_forward_exception */
-void do_early_exception(struct pt_regs *regs, int trapnr);
-
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
 {
 	unsigned long sp = regs->sp;
@@ -209,9 +207,6 @@ static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state)
 	return ghcb;
 }
 
-/* Needed in vc_early_forward_exception */
-void do_early_exception(struct pt_regs *regs, int trapnr);
-
 static inline u64 sev_es_rd_ghcb_msr(void)
 {
 	return __rdmsr(MSR_AMD64_SEV_ES_GHCB);
@@ -1432,7 +1427,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
 		show_regs(regs);
 
 		/* Ask hypervisor to sev_es_terminate */
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 		/* If that fails and we get here - just panic */
 		panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1480,7 +1475,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 
 	/* Do initial setup or terminate the guest */
 	if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))
-		sev_es_terminate(GHCB_SEV_ES_REASON_GENERAL_REQUEST);
+		sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
 
 	vc_ghcb_invalidate(boot_ghcb);
 

arch/x86/mm/Makefile

@@ -2,9 +2,11 @@
 # Kernel does not boot with instrumentation of tlb.c and mem_encrypt*.c
 KCOV_INSTRUMENT_tlb.o			:= n
 KCOV_INSTRUMENT_mem_encrypt.o		:= n
+KCOV_INSTRUMENT_mem_encrypt_amd.o	:= n
 KCOV_INSTRUMENT_mem_encrypt_identity.o	:= n
 
 KASAN_SANITIZE_mem_encrypt.o		:= n
+KASAN_SANITIZE_mem_encrypt_amd.o	:= n
 KASAN_SANITIZE_mem_encrypt_identity.o	:= n
 
 # Disable KCSAN entirely, because otherwise we get warnings that some functions
@@ -13,6 +15,7 @@ KCSAN_SANITIZE := n
 
 ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_mem_encrypt.o		= -pg
+CFLAGS_REMOVE_mem_encrypt_amd.o		= -pg
 CFLAGS_REMOVE_mem_encrypt_identity.o	= -pg
 endif
 
@@ -52,6 +55,8 @@ obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)	+= pkeys.o
 obj-$(CONFIG_RANDOMIZE_MEMORY)			+= kaslr.o
 obj-$(CONFIG_PAGE_TABLE_ISOLATION)		+= pti.o
 
-obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt.o
+obj-$(CONFIG_X86_MEM_ENCRYPT)	+= mem_encrypt.o
+obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_amd.o
+
 obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_identity.o
 obj-$(CONFIG_AMD_MEM_ENCRYPT)	+= mem_encrypt_boot.o

arch/x86/mm/mem_encrypt.c

 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * AMD Memory Encryption Support
+ * Memory Encryption Support Common Code
  *
  * Copyright (C) 2016 Advanced Micro Devices, Inc.
  *
  * Author: Tom Lendacky <thomas.lendacky@amd.com>
  */
 
-#define DISABLE_BRANCH_PROFILING
-
-#include <linux/linkage.h>
-#include <linux/init.h>
-#include <linux/mm.h>
 #include <linux/dma-direct.h>
+#include <linux/dma-mapping.h>
 #include <linux/swiotlb.h>
+#include <linux/cc_platform.h>
 #include <linux/mem_encrypt.h>
-#include <linux/device.h>
-#include <linux/kernel.h>
-#include <linux/bitops.h>
-#include <linux/dma-mapping.h>
 #include <linux/virtio_config.h>
-#include <linux/cc_platform.h>
-
-#include <asm/tlbflush.h>
-#include <asm/fixmap.h>
-#include <asm/setup.h>
-#include <asm/bootparam.h>
-#include <asm/set_memory.h>
-#include <asm/cacheflush.h>
-#include <asm/processor-flags.h>
-#include <asm/msr.h>
-#include <asm/cmdline.h>
-
-#include "mm_internal.h"
-
-/*
- * Since SME related variables are set early in the boot process they must
- * reside in the .data section so as not to be zeroed out when the .bss
- * section is later cleared.
- */
-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);
-
-/* Buffer used for early in-place encryption by BSP, no locking needed */
-static char sme_early_buffer[PAGE_SIZE] __initdata __aligned(PAGE_SIZE);
-
-/*
- * This routine does not change the underlying encryption setting of the
- * page(s) that map this memory. It assumes that eventually the memory is
- * meant to be accessed as either encrypted or decrypted but the contents
- * are currently not in the desired state.
- *
- * This routine follows the steps outlined in the AMD64 Architecture
- * Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place.
- */
-static void __init __sme_early_enc_dec(resource_size_t paddr,
-				       unsigned long size, bool enc)
-{
-	void *src, *dst;
-	size_t len;
-
-	if (!sme_me_mask)
-		return;
-
-	wbinvd();
-
-	/*
-	 * There are limited number of early mapping slots, so map (at most)
-	 * one page at time.
-	 */
-	while (size) {
-		len = min_t(size_t, sizeof(sme_early_buffer), size);
-
-		/*
-		 * Create mappings for the current and desired format of
-		 * the memory. Use a write-protected mapping for the source.
-		 */
-		src = enc ? early_memremap_decrypted_wp(paddr, len) :
-			    early_memremap_encrypted_wp(paddr, len);
-
-		dst = enc ? early_memremap_encrypted(paddr, len) :
-			    early_memremap_decrypted(paddr, len);
-
-		/*
-		 * If a mapping can't be obtained to perform the operation,
-		 * then eventual access of that area in the desired mode
-		 * will cause a crash.
-		 */
-		BUG_ON(!src || !dst);
-
-		/*
-		 * Use a temporary buffer, of cache-line multiple size, to
-		 * avoid data corruption as documented in the APM.
-		 */
-		memcpy(sme_early_buffer, src, len);
-		memcpy(dst, sme_early_buffer, len);
-
-		early_memunmap(dst, len);
-		early_memunmap(src, len);
-
-		paddr += len;
-		size -= len;
-	}
-}
-
-void __init sme_early_encrypt(resource_size_t paddr, unsigned long size)
-{
-	__sme_early_enc_dec(paddr, size, true);
-}
-
-void __init sme_early_decrypt(resource_size_t paddr, unsigned long size)
-{
-	__sme_early_enc_dec(paddr, size, false);
-}
-
-static void __init __sme_early_map_unmap_mem(void *vaddr, unsigned long size,
-					     bool map)
-{
-	unsigned long paddr = (unsigned long)vaddr - __PAGE_OFFSET;
-	pmdval_t pmd_flags, pmd;
-
-	/* Use early_pmd_flags but remove the encryption mask */
-	pmd_flags = __sme_clr(early_pmd_flags);
-
-	do {
-		pmd = map ? (paddr & PMD_MASK) + pmd_flags : 0;
-		__early_make_pgtable((unsigned long)vaddr, pmd);
-
-		vaddr += PMD_SIZE;
-		paddr += PMD_SIZE;
-		size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
-	} while (size);
-
-	flush_tlb_local();
-}
-
-void __init sme_unmap_bootdata(char *real_mode_data)
-{
-	struct boot_params *boot_data;
-	unsigned long cmdline_paddr;
-
-	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
-		return;
-
-	/* Get the command line address before unmapping the real_mode_data */
-	boot_data = (struct boot_params *)real_mode_data;
-	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
-
-	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), false);
-
-	if (!cmdline_paddr)
-		return;
-
-	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, false);
-}
-
-void __init sme_map_bootdata(char *real_mode_data)
-{
-	struct boot_params *boot_data;
-	unsigned long cmdline_paddr;
-
-	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
-		return;
-
-	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
-
-	/* Get the command line address after mapping the real_mode_data */
-	boot_data = (struct boot_params *)real_mode_data;
-	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
-
-	if (!cmdline_paddr)
-		return;
-
-	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
-}
-
-void __init sme_early_init(void)
-{
-	unsigned int i;
-
-	if (!sme_me_mask)
-		return;
-
-	early_pmd_flags = __sme_set(early_pmd_flags);
-
-	__supported_pte_mask = __sme_set(__supported_pte_mask);
-
-	/* Update the protection map with memory encryption mask */
-	for (i = 0; i < ARRAY_SIZE(protection_map); i++)
-		protection_map[i] = pgprot_encrypted(protection_map[i]);
-
-	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
-		swiotlb_force = SWIOTLB_FORCE;
-}
-
-void __init sev_setup_arch(void)
-{
-	phys_addr_t total_mem = memblock_phys_mem_size();
-	unsigned long size;
-
-	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
-		return;
-
-	/*
-	 * For SEV, all DMA has to occur via shared/unencrypted pages.
-	 * SEV uses SWIOTLB to make this happen without changing device
-	 * drivers. However, depending on the workload being run, the
-	 * default 64MB of SWIOTLB may not be enough and SWIOTLB may
-	 * run out of buffers for DMA, resulting in I/O errors and/or
-	 * performance degradation especially with high I/O workloads.
-	 *
-	 * Adjust the default size of SWIOTLB for SEV guests using
-	 * a percentage of guest memory for SWIOTLB buffers.
-	 * Also, as the SWIOTLB bounce buffer memory is allocated
-	 * from low memory, ensure that the adjusted size is within
-	 * the limits of low available memory.
-	 *
-	 * The percentage of guest memory used here for SWIOTLB buffers
-	 * is more of an approximation of the static adjustment which
-	 * 64MB for <1G, and ~128M to 256M for 1G-to-4G, i.e., the 6%
-	 */
-	size = total_mem * 6 / 100;
-	size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);
-	swiotlb_adjust_size(size);
-}
-
-static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
-{
-	unsigned long pfn = 0;
-	pgprot_t prot;
-
-	switch (level) {
-	case PG_LEVEL_4K:
-		pfn = pte_pfn(*kpte);
-		prot = pte_pgprot(*kpte);
-		break;
-	case PG_LEVEL_2M:
-		pfn = pmd_pfn(*(pmd_t *)kpte);
-		prot = pmd_pgprot(*(pmd_t *)kpte);
-		break;
-	case PG_LEVEL_1G:
-		pfn = pud_pfn(*(pud_t *)kpte);
-		prot = pud_pgprot(*(pud_t *)kpte);
-		break;
-	default:
-		WARN_ONCE(1, "Invalid level for kpte\n");
-		return 0;
-	}
-
-	if (ret_prot)
-		*ret_prot = prot;
-
-	return pfn;
-}
-
-void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc)
-{
-#ifdef CONFIG_PARAVIRT
-	unsigned long sz = npages << PAGE_SHIFT;
-	unsigned long vaddr_end = vaddr + sz;
-
-	while (vaddr < vaddr_end) {
-		int psize, pmask, level;
-		unsigned long pfn;
-		pte_t *kpte;
-
-		kpte = lookup_address(vaddr, &level);
-		if (!kpte || pte_none(*kpte)) {
-			WARN_ONCE(1, "kpte lookup for vaddr\n");
-			return;
-		}
-
-		pfn = pg_level_to_pfn(level, kpte, NULL);
-		if (!pfn)
-			continue;
-
-		psize = page_level_size(level);
-		pmask = page_level_mask(level);
-
-		notify_page_enc_status_changed(pfn, psize >> PAGE_SHIFT, enc);
-
-		vaddr = (vaddr & pmask) + psize;
-	}
-#endif
-}
-
-static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
-{
-	pgprot_t old_prot, new_prot;
-	unsigned long pfn, pa, size;
-	pte_t new_pte;
-
-	pfn = pg_level_to_pfn(level, kpte, &old_prot);
-	if (!pfn)
-		return;
-
-	new_prot = old_prot;
-	if (enc)
-		pgprot_val(new_prot) |= _PAGE_ENC;
-	else
-		pgprot_val(new_prot) &= ~_PAGE_ENC;
-
-	/* If prot is same then do nothing. */
-	if (pgprot_val(old_prot) == pgprot_val(new_prot))
-		return;
-
-	pa = pfn << PAGE_SHIFT;
-	size = page_level_size(level);
-
-	/*
-	 * We are going to perform in-place en-/decryption and change the
-	 * physical page attribute from C=1 to C=0 or vice versa. Flush the
-	 * caches to ensure that data gets accessed with the correct C-bit.
-	 */
-	clflush_cache_range(__va(pa), size);
-
-	/* Encrypt/decrypt the contents in-place */
-	if (enc)
-		sme_early_encrypt(pa, size);
-	else
-		sme_early_decrypt(pa, size);
-
-	/* Change the page encryption mask. */
-	new_pte = pfn_pte(pfn, new_prot);
-	set_pte_atomic(kpte, new_pte);
-}
-
-static int __init early_set_memory_enc_dec(unsigned long vaddr,
-					   unsigned long size, bool enc)
-{
-	unsigned long vaddr_end, vaddr_next, start;
-	unsigned long psize, pmask;
-	int split_page_size_mask;
-	int level, ret;
-	pte_t *kpte;
-
-	start = vaddr;
-	vaddr_next = vaddr;
-	vaddr_end = vaddr + size;
-
-	for (; vaddr < vaddr_end; vaddr = vaddr_next) {
-		kpte = lookup_address(vaddr, &level);
-		if (!kpte || pte_none(*kpte)) {
-			ret = 1;
-			goto out;
-		}
-
-		if (level == PG_LEVEL_4K) {
-			__set_clr_pte_enc(kpte, level, enc);
-			vaddr_next = (vaddr & PAGE_MASK) + PAGE_SIZE;
-			continue;
-		}
-
-		psize = page_level_size(level);
-		pmask = page_level_mask(level);
-
-		/*
-		 * Check whether we can change the large page in one go.
-		 * We request a split when the address is not aligned and
-		 * the number of pages to set/clear encryption bit is smaller
-		 * than the number of pages in the large page.
-		 */
-		if (vaddr == (vaddr & pmask) &&
-		    ((vaddr_end - vaddr) >= psize)) {
-			__set_clr_pte_enc(kpte, level, enc);
-			vaddr_next = (vaddr & pmask) + psize;
-			continue;
-		}
-
-		/*
-		 * The virtual address is part of a larger page, create the next
-		 * level page table mapping (4K or 2M). If it is part of a 2M
-		 * page then we request a split of the large page into 4K
-		 * chunks. A 1GB large page is split into 2M pages, resp.
-		 */
-		if (level == PG_LEVEL_2M)
-			split_page_size_mask = 0;
-		else
-			split_page_size_mask = 1 << PG_LEVEL_2M;
-
-		/*
-		 * kernel_physical_mapping_change() does not flush the TLBs, so
-		 * a TLB flush is required after we exit from the for loop.
-		 */
-		kernel_physical_mapping_change(__pa(vaddr & pmask),
-					       __pa((vaddr_end & pmask) + psize),
-					       split_page_size_mask);
-	}
-
-	ret = 0;
-
-	notify_range_enc_status_changed(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc);
-out:
-	__flush_tlb_all();
-	return ret;
-}
-
-int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size)
-{
-	return early_set_memory_enc_dec(vaddr, size, false);
-}
-
-int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
-{
-	return early_set_memory_enc_dec(vaddr, size, true);
-}
-
-void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc)
-{
-	notify_range_enc_status_changed(vaddr, npages, enc);
-}
 
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)
@@ -441,30 +40,6 @@ bool force_dma_unencrypted(struct device *dev)
 	return false;
 }
 
-void __init mem_encrypt_free_decrypted_mem(void)
-{
-	unsigned long vaddr, vaddr_end, npages;
-	int r;
-
-	vaddr = (unsigned long)__start_bss_decrypted_unused;
-	vaddr_end = (unsigned long)__end_bss_decrypted;
-	npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
-
-	/*
-	 * The unused memory range was mapped decrypted, change the encryption
-	 * attribute from decrypted to encrypted before freeing it.
-	 */
-	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
-		r = set_memory_encrypted(vaddr, npages);
-		if (r) {
-			pr_warn("failed to free unused decrypted pages\n");
-			return;
-		}
-	}
-
-	free_init_pages("unused decrypted", vaddr, vaddr_end);
-}
-
 static void print_mem_encrypt_feature_info(void)
 {
 	pr_info("AMD Memory Encryption Features active:");
@@ -493,20 +68,12 @@ static void print_mem_encrypt_feature_info(void)
 /* Architecture __weak replacement functions */
 void __init mem_encrypt_init(void)
 {
-	if (!sme_me_mask)
+	if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		return;
 
 	/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
 	swiotlb_update_mem_attributes();
 
-	/*
-	 * With SEV, we need to unroll the rep string I/O instructions,
-	 * but SEV-ES supports them through the #VC handler.
-	 */
-	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&
-	    !cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
-		static_branch_enable(&sev_enable_key);
-
 	print_mem_encrypt_feature_info();
 }
 

arch/x86/mm/mem_encrypt_amd.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Memory Encryption Support
+ *
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ */
+
+#define DISABLE_BRANCH_PROFILING
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/dma-direct.h>
+#include <linux/swiotlb.h>
+#include <linux/mem_encrypt.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/dma-mapping.h>
+#include <linux/virtio_config.h>
+#include <linux/cc_platform.h>
+
+#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
+#include <asm/setup.h>
+#include <asm/bootparam.h>
+#include <asm/set_memory.h>
+#include <asm/cacheflush.h>
+#include <asm/processor-flags.h>
+#include <asm/msr.h>
+#include <asm/cmdline.h>
+
+#include "mm_internal.h"
+
+/*
+ * Since SME related variables are set early in the boot process they must
+ * reside in the .data section so as not to be zeroed out when the .bss
+ * section is later cleared.
+ */
+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);
+
+/* Buffer used for early in-place encryption by BSP, no locking needed */
+static char sme_early_buffer[PAGE_SIZE] __initdata __aligned(PAGE_SIZE);
+
+/*
+ * This routine does not change the underlying encryption setting of the
+ * page(s) that map this memory. It assumes that eventually the memory is
+ * meant to be accessed as either encrypted or decrypted but the contents
+ * are currently not in the desired state.
+ *
+ * This routine follows the steps outlined in the AMD64 Architecture
+ * Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place.
+ */
+static void __init __sme_early_enc_dec(resource_size_t paddr,
+				       unsigned long size, bool enc)
+{
+	void *src, *dst;
+	size_t len;
+
+	if (!sme_me_mask)
+		return;
+
+	wbinvd();
+
+	/*
+	 * There are limited number of early mapping slots, so map (at most)
+	 * one page at time.
+	 */
+	while (size) {
+		len = min_t(size_t, sizeof(sme_early_buffer), size);
+
+		/*
+		 * Create mappings for the current and desired format of
+		 * the memory. Use a write-protected mapping for the source.
+		 */
+		src = enc ? early_memremap_decrypted_wp(paddr, len) :
+			    early_memremap_encrypted_wp(paddr, len);
+
+		dst = enc ? early_memremap_encrypted(paddr, len) :
+			    early_memremap_decrypted(paddr, len);
+
+		/*
+		 * If a mapping can't be obtained to perform the operation,
+		 * then eventual access of that area in the desired mode
+		 * will cause a crash.
+		 */
+		BUG_ON(!src || !dst);
+
+		/*
+		 * Use a temporary buffer, of cache-line multiple size, to
+		 * avoid data corruption as documented in the APM.
+		 */
+		memcpy(sme_early_buffer, src, len);
+		memcpy(dst, sme_early_buffer, len);
+
+		early_memunmap(dst, len);
+		early_memunmap(src, len);
+
+		paddr += len;
+		size -= len;
+	}
+}
+
+void __init sme_early_encrypt(resource_size_t paddr, unsigned long size)
+{
+	__sme_early_enc_dec(paddr, size, true);
+}
+
+void __init sme_early_decrypt(resource_size_t paddr, unsigned long size)
+{
+	__sme_early_enc_dec(paddr, size, false);
+}
+
+static void __init __sme_early_map_unmap_mem(void *vaddr, unsigned long size,
+					     bool map)
+{
+	unsigned long paddr = (unsigned long)vaddr - __PAGE_OFFSET;
+	pmdval_t pmd_flags, pmd;
+
+	/* Use early_pmd_flags but remove the encryption mask */
+	pmd_flags = __sme_clr(early_pmd_flags);
+
+	do {
+		pmd = map ? (paddr & PMD_MASK) + pmd_flags : 0;
+		__early_make_pgtable((unsigned long)vaddr, pmd);
+
+		vaddr += PMD_SIZE;
+		paddr += PMD_SIZE;
+		size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
+	} while (size);
+
+	flush_tlb_local();
+}
+
+void __init sme_unmap_bootdata(char *real_mode_data)
+{
+	struct boot_params *boot_data;
+	unsigned long cmdline_paddr;
+
+	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
+		return;
+
+	/* Get the command line address before unmapping the real_mode_data */
+	boot_data = (struct boot_params *)real_mode_data;
+	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
+
+	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), false);
+
+	if (!cmdline_paddr)
+		return;
+
+	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, false);
+}
+
+void __init sme_map_bootdata(char *real_mode_data)
+{
+	struct boot_params *boot_data;
+	unsigned long cmdline_paddr;
+
+	if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
+		return;
+
+	__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
+
+	/* Get the command line address after mapping the real_mode_data */
+	boot_data = (struct boot_params *)real_mode_data;
+	cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
+
+	if (!cmdline_paddr)
+		return;
+
+	__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
+}
+
+void __init sme_early_init(void)
+{
+	unsigned int i;
+
+	if (!sme_me_mask)
+		return;
+
+	early_pmd_flags = __sme_set(early_pmd_flags);
+
+	__supported_pte_mask = __sme_set(__supported_pte_mask);
+
+	/* Update the protection map with memory encryption mask */
+	for (i = 0; i < ARRAY_SIZE(protection_map); i++)
+		protection_map[i] = pgprot_encrypted(protection_map[i]);
+
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+		swiotlb_force = SWIOTLB_FORCE;
+}
+
+void __init sev_setup_arch(void)
+{
+	phys_addr_t total_mem = memblock_phys_mem_size();
+	unsigned long size;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+		return;
+
+	/*
+	 * For SEV, all DMA has to occur via shared/unencrypted pages.
+	 * SEV uses SWIOTLB to make this happen without changing device
+	 * drivers. However, depending on the workload being run, the
+	 * default 64MB of SWIOTLB may not be enough and SWIOTLB may
+	 * run out of buffers for DMA, resulting in I/O errors and/or
+	 * performance degradation especially with high I/O workloads.
+	 *
+	 * Adjust the default size of SWIOTLB for SEV guests using
+	 * a percentage of guest memory for SWIOTLB buffers.
+	 * Also, as the SWIOTLB bounce buffer memory is allocated
+	 * from low memory, ensure that the adjusted size is within
+	 * the limits of low available memory.
+	 *
+	 * The percentage of guest memory used here for SWIOTLB buffers
+	 * is more of an approximation of the static adjustment which
+	 * 64MB for <1G, and ~128M to 256M for 1G-to-4G, i.e., the 6%
+	 */
+	size = total_mem * 6 / 100;
+	size = clamp_val(size, IO_TLB_DEFAULT_SIZE, SZ_1G);
+	swiotlb_adjust_size(size);
+}
+
+static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
+{
+	unsigned long pfn = 0;
+	pgprot_t prot;
+
+	switch (level) {
+	case PG_LEVEL_4K:
+		pfn = pte_pfn(*kpte);
+		prot = pte_pgprot(*kpte);
+		break;
+	case PG_LEVEL_2M:
+		pfn = pmd_pfn(*(pmd_t *)kpte);
+		prot = pmd_pgprot(*(pmd_t *)kpte);
+		break;
+	case PG_LEVEL_1G:
+		pfn = pud_pfn(*(pud_t *)kpte);
+		prot = pud_pgprot(*(pud_t *)kpte);
+		break;
+	default:
+		WARN_ONCE(1, "Invalid level for kpte\n");
+		return 0;
+	}
+
+	if (ret_prot)
+		*ret_prot = prot;
+
+	return pfn;
+}
+
+void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc)
+{
+#ifdef CONFIG_PARAVIRT
+	unsigned long sz = npages << PAGE_SHIFT;
+	unsigned long vaddr_end = vaddr + sz;
+
+	while (vaddr < vaddr_end) {
+		int psize, pmask, level;
+		unsigned long pfn;
+		pte_t *kpte;
+
+		kpte = lookup_address(vaddr, &level);
+		if (!kpte || pte_none(*kpte)) {
+			WARN_ONCE(1, "kpte lookup for vaddr\n");
+			return;
+		}
+
+		pfn = pg_level_to_pfn(level, kpte, NULL);
+		if (!pfn)
+			continue;
+
+		psize = page_level_size(level);
+		pmask = page_level_mask(level);
+
+		notify_page_enc_status_changed(pfn, psize >> PAGE_SHIFT, enc);
+
+		vaddr = (vaddr & pmask) + psize;
+	}
+#endif
+}
+
+static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
+{
+	pgprot_t old_prot, new_prot;
+	unsigned long pfn, pa, size;
+	pte_t new_pte;
+
+	pfn = pg_level_to_pfn(level, kpte, &old_prot);
+	if (!pfn)
+		return;
+
+	new_prot = old_prot;
+	if (enc)
+		pgprot_val(new_prot) |= _PAGE_ENC;
+	else
+		pgprot_val(new_prot) &= ~_PAGE_ENC;
+
+	/* If prot is same then do nothing. */
+	if (pgprot_val(old_prot) == pgprot_val(new_prot))
+		return;
+
+	pa = pfn << PAGE_SHIFT;
+	size = page_level_size(level);
+
+	/*
+	 * We are going to perform in-place en-/decryption and change the
+	 * physical page attribute from C=1 to C=0 or vice versa. Flush the
+	 * caches to ensure that data gets accessed with the correct C-bit.
+	 */
+	clflush_cache_range(__va(pa), size);
+
+	/* Encrypt/decrypt the contents in-place */
+	if (enc)
+		sme_early_encrypt(pa, size);
+	else
+		sme_early_decrypt(pa, size);
+
+	/* Change the page encryption mask. */
+	new_pte = pfn_pte(pfn, new_prot);
+	set_pte_atomic(kpte, new_pte);
+}
+
+static int __init early_set_memory_enc_dec(unsigned long vaddr,
+					   unsigned long size, bool enc)
+{
+	unsigned long vaddr_end, vaddr_next, start;
+	unsigned long psize, pmask;
+	int split_page_size_mask;
+	int level, ret;
+	pte_t *kpte;
+
+	start = vaddr;
+	vaddr_next = vaddr;
+	vaddr_end = vaddr + size;
+
+	for (; vaddr < vaddr_end; vaddr = vaddr_next) {
+		kpte = lookup_address(vaddr, &level);
+		if (!kpte || pte_none(*kpte)) {
+			ret = 1;
+			goto out;
+		}
+
+		if (level == PG_LEVEL_4K) {
+			__set_clr_pte_enc(kpte, level, enc);
+			vaddr_next = (vaddr & PAGE_MASK) + PAGE_SIZE;
+			continue;
+		}
+
+		psize = page_level_size(level);
+		pmask = page_level_mask(level);
+
+		/*
+		 * Check whether we can change the large page in one go.
+		 * We request a split when the address is not aligned and
+		 * the number of pages to set/clear encryption bit is smaller
+		 * than the number of pages in the large page.
+		 */
+		if (vaddr == (vaddr & pmask) &&
+		    ((vaddr_end - vaddr) >= psize)) {
+			__set_clr_pte_enc(kpte, level, enc);
+			vaddr_next = (vaddr & pmask) + psize;
+			continue;
+		}
+
+		/*
+		 * The virtual address is part of a larger page, create the next
+		 * level page table mapping (4K or 2M). If it is part of a 2M
+		 * page then we request a split of the large page into 4K
+		 * chunks. A 1GB large page is split into 2M pages, resp.
+		 */
+		if (level == PG_LEVEL_2M)
+			split_page_size_mask = 0;
+		else
+			split_page_size_mask = 1 << PG_LEVEL_2M;
+
+		/*
+		 * kernel_physical_mapping_change() does not flush the TLBs, so
+		 * a TLB flush is required after we exit from the for loop.
+		 */
+		kernel_physical_mapping_change(__pa(vaddr & pmask),
+					       __pa((vaddr_end & pmask) + psize),
+					       split_page_size_mask);
+	}
+
+	ret = 0;
+
+	notify_range_enc_status_changed(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc);
+out:
+	__flush_tlb_all();
+	return ret;
+}
+
+int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size)
+{
+	return early_set_memory_enc_dec(vaddr, size, false);
+}
+
+int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)
+{
+	return early_set_memory_enc_dec(vaddr, size, true);
+}
+
+void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc)
+{
+	notify_range_enc_status_changed(vaddr, npages, enc);
+}
+
+void __init mem_encrypt_free_decrypted_mem(void)
+{
+	unsigned long vaddr, vaddr_end, npages;
+	int r;
+
+	vaddr = (unsigned long)__start_bss_decrypted_unused;
+	vaddr_end = (unsigned long)__end_bss_decrypted;
+	npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
+
+	/*
+	 * The unused memory range was mapped decrypted, change the encryption
+	 * attribute from decrypted to encrypted before freeing it.
+	 */
+	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
+		r = set_memory_encrypted(vaddr, npages);
+		if (r) {
+			pr_warn("failed to free unused decrypted pages\n");
+			return;
+		}
+	}
+
+	free_init_pages("unused decrypted", vaddr, vaddr_end);
+}

include/linux/cc_platform.h

@@ -61,6 +61,17 @@ enum cc_attr {
 	 * Examples include SEV-ES.
 	 */
 	CC_ATTR_GUEST_STATE_ENCRYPT,
+
+	/**
+	 * @CC_ATTR_GUEST_UNROLL_STRING_IO: String I/O is implemented with
+	 *                                  IN/OUT instructions
+	 *
+	 * The platform/OS is running as a guest/virtual machine and uses
+	 * IN/OUT instructions in place of string I/O.
+	 *
+	 * Examples include TDX guest & SEV.
+	 */
+	CC_ATTR_GUEST_UNROLL_STRING_IO,
 };
 
 #ifdef CONFIG_ARCH_HAS_CC_PLATFORM