diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ff653d608d5f781a1a00bf817d521ef93fa55a9c..1e720626069a35ef10ca880855ef6e6293808850 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -638,11 +638,11 @@ static void __init trim_snb_memory(void)
 	 * them from accessing certain memory ranges, namely anything below
 	 * 1M and in the pages listed in bad_pages[] above.
 	 *
-	 * To avoid these pages being ever accessed by SNB gfx devices
-	 * reserve all memory below the 1 MB mark and bad_pages that have
-	 * not already been reserved at boot time.
+	 * To avoid these pages being ever accessed by SNB gfx devices reserve
+	 * bad_pages that have not already been reserved at boot time.
+	 * All memory below the 1 MB mark is anyway reserved later during
+	 * setup_arch(), so there is no need to reserve it here.
 	 */
-	memblock_reserve(0, 1<<20);
 
 	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {
 		if (memblock_reserve(bad_pages[i], PAGE_SIZE))
@@ -734,14 +734,14 @@ static void __init early_reserve_memory(void)
 	 * The first 4Kb of memory is a BIOS owned area, but generally it is
 	 * not listed as such in the E820 table.
 	 *
-	 * Reserve the first memory page and typically some additional
-	 * memory (64KiB by default) since some BIOSes are known to corrupt
-	 * low memory. See the Kconfig help text for X86_RESERVE_LOW.
+	 * Reserve the first 64K of memory since some BIOSes are known to
+	 * corrupt low memory. After the real mode trampoline is allocated the
+	 * rest of the memory below 640k is reserved.
 	 *
 	 * In addition, make sure page 0 is always reserved because on
 	 * systems with L1TF its contents can be leaked to user processes.
 	 */
-	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
+	memblock_reserve(0, SZ_64K);
 
 	early_reserve_initrd();
 
@@ -752,6 +752,7 @@ static void __init early_reserve_memory(void)
 
 	reserve_ibft_region();
 	reserve_bios_regions();
+	trim_snb_memory();
 }
 
 /*
@@ -1082,14 +1083,20 @@ void __init setup_arch(char **cmdline_p)
 			(max_pfn_mapped<<PAGE_SHIFT) - 1);
 #endif
 
-	reserve_real_mode();
-
 	/*
-	 * Reserving memory causing GPU hangs on Sandy Bridge integrated
-	 * graphics devices should be done after we allocated memory under
-	 * 1M for the real mode trampoline.
+	 * Find free memory for the real mode trampoline and place it
+	 * there.
+	 * If there is not enough free memory under 1M, on EFI-enabled
+	 * systems there will be additional attempt to reclaim the memory
+	 * for the real mode trampoline at efi_free_boot_services().
+	 *
+	 * Unconditionally reserve the entire first 1M of RAM because
+	 * BIOSes are know to corrupt low memory and several
+	 * hundred kilobytes are not worth complex detection what memory gets
+	 * clobbered. Moreover, on machines with SandyBridge graphics or in
+	 * setups that use crashkernel the entire 1M is reserved anyway.
 	 */
-	trim_snb_memory();
+	reserve_real_mode();
 
 	init_mem_mapping();
 
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 7850111008a8b87e4c5a63ea984fcfec18af8184..b15ebfe40a73ea16660d68c6aa624094bbe8a8ad 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -450,6 +450,18 @@ void __init efi_free_boot_services(void)
 			size -= rm_size;
 		}
 
+		/*
+		 * Don't free memory under 1M for two reasons:
+		 * - BIOS might clobber it
+		 * - Crash kernel needs it to be reserved
+		 */
+		if (start + size < SZ_1M)
+			continue;
+		if (start < SZ_1M) {
+			size -= (SZ_1M - start);
+			start = SZ_1M;
+		}
+
 		memblock_free_late(start, size);
 	}
 
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 2e1c1bec0f9e704cf38df5a650c440639313237f..6534c92d0f83f0baed036717f465235b011db851 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -29,14 +29,16 @@ void __init reserve_real_mode(void)
 
 	/* Has to be under 1M so we can execute real-mode AP code. */
 	mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
-	if (!mem) {
+	if (!mem)
 		pr_info("No sub-1M memory is available for the trampoline\n");
-		return;
-	}
+	else
+		set_real_mode_mem(mem);
 
-	memblock_reserve(mem, size);
-	set_real_mode_mem(mem);
-	crash_reserve_low_1M();
+	/*
+	 * Unconditionally reserve the entire fisrt 1M, see comment in
+	 * setup_arch().
+	 */
+	memblock_reserve(0, SZ_1M);
 }
 
 static void sme_sev_setup_real_mode(struct trampoline_header *th)