diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index aa91bebc0fe978e2398878255b126ecc2fd4a975..05742f641a0625826e1a7f9453cd73868cb39456 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -24,6 +24,7 @@
 
 /* These actually do the work of building the kernel identity maps. */
 #include <linux/pgtable.h>
+#include <asm/cmpxchg.h>
 #include <asm/trap_pf.h>
 #include <asm/trapnr.h>
 #include <asm/init.h>
@@ -165,6 +166,138 @@ void finalize_identity_maps(void)
 	write_cr3(top_level_pgt);
 }
 
+static pte_t *split_large_pmd(struct x86_mapping_info *info,
+			      pmd_t *pmdp, unsigned long __address)
+{
+	unsigned long page_flags;
+	unsigned long address;
+	pte_t *pte;
+	pmd_t pmd;
+	int i;
+
+	pte = (pte_t *)info->alloc_pgt_page(info->context);
+	if (!pte)
+		return NULL;
+
+	address     = __address & PMD_MASK;
+	/* No large page - clear PSE flag */
+	page_flags  = info->page_flag & ~_PAGE_PSE;
+
+	/* Populate the PTEs */
+	for (i = 0; i < PTRS_PER_PMD; i++) {
+		set_pte(&pte[i], __pte(address | page_flags));
+		address += PAGE_SIZE;
+	}
+
+	/*
+	 * Ideally we need to clear the large PMD first and do a TLB
+	 * flush before we write the new PMD. But the 2M range of the
+	 * PMD might contain the code we execute and/or the stack
+	 * we are on, so we can't do that. But that should be safe here
+	 * because we are going from large to small mappings and we are
+	 * also the only user of the page-table, so there is no chance
+	 * of a TLB multihit.
+	 */
+	pmd = __pmd((unsigned long)pte | info->kernpg_flag);
+	set_pmd(pmdp, pmd);
+	/* Flush TLB to establish the new PMD */
+	write_cr3(top_level_pgt);
+
+	return pte + pte_index(__address);
+}
+
+static void clflush_page(unsigned long address)
+{
+	unsigned int flush_size;
+	char *cl, *start, *end;
+
+	/*
+	 * Hardcode cl-size to 64 - CPUID can't be used here because that might
+	 * cause another #VC exception and the GHCB is not ready to use yet.
+	 */
+	flush_size = 64;
+	start      = (char *)(address & PAGE_MASK);
+	end        = start + PAGE_SIZE;
+
+	/*
+	 * First make sure there are no pending writes on the cache-lines to
+	 * flush.
+	 */
+	asm volatile("mfence" : : : "memory");
+
+	for (cl = start; cl != end; cl += flush_size)
+		clflush(cl);
+}
+
+static int set_clr_page_flags(struct x86_mapping_info *info,
+			      unsigned long address,
+			      pteval_t set, pteval_t clr)
+{
+	pgd_t *pgdp = (pgd_t *)top_level_pgt;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+	pte_t *ptep, pte;
+
+	/*
+	 * First make sure there is a PMD mapping for 'address'.
+	 * It should already exist, but keep things generic.
+	 *
+	 * To map the page just read from it and fault it in if there is no
+	 * mapping yet. add_identity_map() can't be called here because that
+	 * would unconditionally map the address on PMD level, destroying any
+	 * PTE-level mappings that might already exist. Use assembly here so
+	 * the access won't be optimized away.
+	 */
+	asm volatile("mov %[address], %%r9"
+		     :: [address] "g" (*(unsigned long *)address)
+		     : "r9", "memory");
+
+	/*
+	 * The page is mapped at least with PMD size - so skip checks and walk
+	 * directly to the PMD.
+	 */
+	p4dp = p4d_offset(pgdp, address);
+	pudp = pud_offset(p4dp, address);
+	pmdp = pmd_offset(pudp, address);
+
+	if (pmd_large(*pmdp))
+		ptep = split_large_pmd(info, pmdp, address);
+	else
+		ptep = pte_offset_kernel(pmdp, address);
+
+	if (!ptep)
+		return -ENOMEM;
+
+	/*
+	 * Changing encryption attributes of a page requires to flush it from
+	 * the caches.
+	 */
+	if ((set | clr) & _PAGE_ENC)
+		clflush_page(address);
+
+	/* Update PTE */
+	pte = *ptep;
+	pte = pte_set_flags(pte, set);
+	pte = pte_clear_flags(pte, clr);
+	set_pte(ptep, pte);
+
+	/* Flush TLB after changing encryption attribute */
+	write_cr3(top_level_pgt);
+
+	return 0;
+}
+
+int set_page_decrypted(unsigned long address)
+{
+	return set_clr_page_flags(&mapping_info, address, 0, _PAGE_ENC);
+}
+
+int set_page_encrypted(unsigned long address)
+{
+	return set_clr_page_flags(&mapping_info, address, _PAGE_ENC, 0);
+}
+
 static void do_pf_error(const char *msg, unsigned long error_code,
 			unsigned long address, unsigned long ip)
 {
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index eaa8b45ebccbc952f58c511f410ea609f555ba32..01c0fb3417ca7242663dd1af3b3053de26f40c6b 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -98,6 +98,8 @@ static inline void choose_random_location(unsigned long input,
 #endif
 
 #ifdef CONFIG_X86_64
+extern int set_page_decrypted(unsigned long address);
+extern int set_page_encrypted(unsigned long address);
 extern unsigned char _pgtable[];
 #endif