On Mon, 08 Sep 2025 12:28:28 +0900 (JST)
YASUOKA Masahiko <yasuoka@openbsd.org> wrote:
> Hi,
> 
> # moved from bug@ to tech@
> 
> On Sun, 7 Sep 2025 11:57:52 -0700
> Mike Larkin <mlarkin@nested.page> wrote:
>> On Fri, Sep 05, 2025 at 09:18:49AM +0100, Stuart Henderson wrote:
>>> "machine mem" takes an optional argument to either restrict max memory, or
>>> add/remove certain ranges - https://man.openbsd.org/amd64/boot#memory - you
>>> could try excluding some of the memory ranges from the list you showed.
>>>
>> 
>> N.B. - machine mem to restrict memory doesn't work on EFI.
> 
> I didn't aware of this problem.
> 
> ok?
> 
> Don't reset bios_memmap when exiting if it's modified by the operator.

Let me tweak the diff.

> Index: sys/arch/amd64/stand/efiboot/efiboot.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/amd64/stand/efiboot/efiboot.c,v
> diff -u -p -r1.43 efiboot.c
> --- sys/arch/amd64/stand/efiboot/efiboot.c	27 Aug 2025 09:08:12 -0000	1.43
> +++ sys/arch/amd64/stand/efiboot/efiboot.c	8 Sep 2025 03:23:45 -0000
(snip)
> @@ -350,14 +346,37 @@ efi_memprobe_internal(void)
>  	status = BS->GetMemoryMap(&siz, NULL, &mapkey, &mmsiz, &mmver);
>  	if (status != EFI_BUFFER_TOO_SMALL)
>  		panic("cannot get the size of memory map");
> -	mm0 = alloc(siz);
> -	status = BS->GetMemoryMap(&siz, mm0, &mapkey, &mmsiz, &mmver);
> +	mm = alloc(siz);
> +	status = BS->GetMemoryMap(&siz, mm, &mapkey, &mmsiz, &mmver);
>  	if (status != EFI_SUCCESS)
>  		panic("cannot get the memory map");
> -	n = siz / mmsiz;
> +
>  	mmap_key = mapkey;
>  
> -	for (i = 0, mm = mm0; i < n; i++, mm = NextMemoryDescriptor(mm, mmsiz)){
> +	bios_efiinfo.mmap_desc_ver = mmver;
> +	bios_efiinfo.mmap_desc_size = mmsiz;
> +	bios_efiinfo.mmap_size = siz;
> +	bios_efiinfo.mmap_start = (uintptr_t)mm;
> +
> +	if (bios_memmap_modified)
> +		return (0);
> +
> +	cnvmem = extmem = 0;
> +	bios_memmap[0].type = BIOS_MAP_END;
> +	return (efi_update_bios_memmap());
> +}
> +

I'd like to move the 2 lines before calling efi_update_bios_memmap()
into  efi_update_bios_memmap() is better.

Index: sys/arch/amd64/stand/efiboot/cmd_i386.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/stand/efiboot/cmd_i386.c,v
diff -u -p -r1.3 cmd_i386.c
--- sys/arch/amd64/stand/efiboot/cmd_i386.c	27 Aug 2025 09:08:12 -0000	1.3
+++ sys/arch/amd64/stand/efiboot/cmd_i386.c	8 Sep 2025 03:37:01 -0000
@@ -95,6 +95,7 @@ Xmemory(void)
 		for (i = 1; i < cmd.argc; i++) {
 			char *p;
 			long long addr, size;
+			extern int bios_memmap_modified;
 
 			p = cmd.argv[i];
 
@@ -145,6 +146,7 @@ Xmemory(void)
 					printf("bad OP\n");
 					return 0;
 				}
+				bios_memmap_modified = 1;
 			}
 		}
 	}
Index: sys/arch/amd64/stand/efiboot/efiboot.c
===================================================================
RCS file: /cvs/src/sys/arch/amd64/stand/efiboot/efiboot.c,v
diff -u -p -r1.43 efiboot.c
--- sys/arch/amd64/stand/efiboot/efiboot.c	27 Aug 2025 09:08:12 -0000	1.43
+++ sys/arch/amd64/stand/efiboot/efiboot.c	8 Sep 2025 03:37:01 -0000
@@ -60,6 +60,7 @@ int	 efi_device_path_depth(EFI_DEVICE_PA
 int	 efi_device_path_ncmp(EFI_DEVICE_PATH *, EFI_DEVICE_PATH *, int);
 static void	 efi_heap_init(void);
 static int	 efi_memprobe_internal(void);
+static int	 efi_update_bios_memmap(void);
 static void	 efi_video_init(void);
 static void	 efi_video_reset(void);
 static EFI_STATUS
@@ -283,6 +284,7 @@ efi_device_path_ncmp(EFI_DEVICE_PATH *dp
  ***********************************************************************/
 bios_memmap_t		 bios_memmap[128];
 bios_efiinfo_t		 bios_efiinfo;
+int			 bios_memmap_modified = 0;
 
 static void
 efi_heap_init(void)
@@ -335,13 +337,7 @@ efi_memprobe_internal(void)
 	EFI_STATUS		 status;
 	UINTN			 mapkey, mmsiz, siz;
 	UINT32			 mmver;
-	EFI_MEMORY_DESCRIPTOR	*mm0, *mm;
-	int			 i, n;
-	bios_memmap_t		*bm, bm0;
-	int			 error = 0;
-
-	cnvmem = extmem = 0;
-	bios_memmap[0].type = BIOS_MAP_END;
+	EFI_MEMORY_DESCRIPTOR	*mm;
 
 	if (bios_efiinfo.mmap_start != 0)
 		free((void *)bios_efiinfo.mmap_start, bios_efiinfo.mmap_size);
@@ -350,14 +346,37 @@ efi_memprobe_internal(void)
 	status = BS->GetMemoryMap(&siz, NULL, &mapkey, &mmsiz, &mmver);
 	if (status != EFI_BUFFER_TOO_SMALL)
 		panic("cannot get the size of memory map");
-	mm0 = alloc(siz);
-	status = BS->GetMemoryMap(&siz, mm0, &mapkey, &mmsiz, &mmver);
+	mm = alloc(siz);
+	status = BS->GetMemoryMap(&siz, mm, &mapkey, &mmsiz, &mmver);
 	if (status != EFI_SUCCESS)
 		panic("cannot get the memory map");
-	n = siz / mmsiz;
+
 	mmap_key = mapkey;
 
-	for (i = 0, mm = mm0; i < n; i++, mm = NextMemoryDescriptor(mm, mmsiz)){
+	bios_efiinfo.mmap_desc_ver = mmver;
+	bios_efiinfo.mmap_desc_size = mmsiz;
+	bios_efiinfo.mmap_size = siz;
+	bios_efiinfo.mmap_start = (uintptr_t)mm;
+
+	if (bios_memmap_modified)
+		return (0);
+
+	return (efi_update_bios_memmap());
+}
+
+static int
+efi_update_bios_memmap(void)
+{
+	int			 i, n, error = 0;
+	bios_memmap_t		*bm, bm0;
+	EFI_MEMORY_DESCRIPTOR	*mm;
+
+	cnvmem = extmem = 0;
+	bios_memmap[0].type = BIOS_MAP_END;
+	n = bios_efiinfo.mmap_size / bios_efiinfo.mmap_desc_size;
+	for (i = 0, mm = (EFI_MEMORY_DESCRIPTOR *)bios_efiinfo.mmap_start;
+	    i < n;
+	    i++, mm = NextMemoryDescriptor(mm, bios_efiinfo.mmap_desc_size)) {
 		bm0.type = BIOS_MAP_END;
 		bm0.addr = mm->PhysicalStart;
 		bm0.size = mm->NumberOfPages * EFI_PAGE_SIZE;
@@ -415,12 +434,7 @@ efi_memprobe_internal(void)
 			extmem += bm->size / 1024;
 	}
 
-	bios_efiinfo.mmap_desc_ver = mmver;
-	bios_efiinfo.mmap_desc_size = mmsiz;
-	bios_efiinfo.mmap_size = siz;
-	bios_efiinfo.mmap_start = (uintptr_t)mm0;
-
-	return error;
+	return (error);
 }
 
 /***********************************************************************