* [PATCH v2 0/2] x86/pvh: fix VGA reporting when booted as a PVH guest
@ 2024-04-22 9:52 Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 1/2] x86/video: add boot_video_info offset generation to asm-offsets Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 2/2] x86/pvh: zero VGA information Roger Pau Monne
0 siblings, 2 replies; 4+ messages in thread
From: Roger Pau Monne @ 2024-04-22 9:52 UTC (permalink / raw
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper
Hello,
Following patches are kind of unconnected after v1, but patch 1/2 is
still a helpful improvement.
Patch 2 fixes the (wrong) reporting of VGA information when Xen is
booted as a PVH guest.
Thanks, Roger.
Roger Pau Monne (2):
x86/video: add boot_video_info offset generation to asm-offsets
x86/pvh: zero VGA information
xen/arch/x86/boot/video.S | 83 ++++++++++++-------------------
xen/arch/x86/boot/video.h | 2 +
xen/arch/x86/guest/xen/pvh-boot.c | 9 ++++
xen/arch/x86/setup.c | 1 -
xen/arch/x86/x86_64/asm-offsets.c | 26 ++++++++++
5 files changed, 69 insertions(+), 52 deletions(-)
--
2.44.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/2] x86/video: add boot_video_info offset generation to asm-offsets
2024-04-22 9:52 [PATCH v2 0/2] x86/pvh: fix VGA reporting when booted as a PVH guest Roger Pau Monne
@ 2024-04-22 9:52 ` Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 2/2] x86/pvh: zero VGA information Roger Pau Monne
1 sibling, 0 replies; 4+ messages in thread
From: Roger Pau Monne @ 2024-04-22 9:52 UTC (permalink / raw
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper
Currently the offsets into the boot_video_info struct are manually encoded in
video.S, which is fragile. Generate them in asm-offsets.c and switch the
current code to use those instead.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Changes since v1:
- Style changes.
- Calculate remaining BVI size without referencing specific fields.
---
xen/arch/x86/boot/video.S | 83 ++++++++++++-------------------
xen/arch/x86/x86_64/asm-offsets.c | 26 ++++++++++
2 files changed, 58 insertions(+), 51 deletions(-)
diff --git a/xen/arch/x86/boot/video.S b/xen/arch/x86/boot/video.S
index 0ae04f270f8c..f78906878a16 100644
--- a/xen/arch/x86/boot/video.S
+++ b/xen/arch/x86/boot/video.S
@@ -26,32 +26,13 @@
/* Force 400 scan lines for standard modes (hack to fix bad BIOS behaviour */
#undef CONFIG_VIDEO_400_HACK
-/* Positions of various video parameters passed to the kernel */
-/* (see also include/linux/tty.h) */
-#define PARAM_CURSOR_POS 0x00
-#define PARAM_VIDEO_MODE 0x02
-#define PARAM_VIDEO_COLS 0x03
-#define PARAM_VIDEO_LINES 0x04
-#define PARAM_HAVE_VGA 0x05
-#define PARAM_FONT_POINTS 0x06
-#define PARAM_CAPABILITIES 0x08
-#define PARAM_LFB_LINELENGTH 0x0c
-#define PARAM_LFB_WIDTH 0x0e
-#define PARAM_LFB_HEIGHT 0x10
-#define PARAM_LFB_DEPTH 0x12
-#define PARAM_LFB_BASE 0x14
-#define PARAM_LFB_SIZE 0x18
-#define PARAM_LFB_COLORS 0x1c
-#define PARAM_VESAPM_SEG 0x24
-#define PARAM_VESAPM_OFF 0x26
-#define PARAM_VESA_ATTRIB 0x28
#define _param(param) bootsym(boot_vid_info)+(param)
video: xorw %ax, %ax
movw %ax, %gs # GS is zero
cld
call basic_detect # Basic adapter type testing (EGA/VGA/MDA/CGA)
- cmpb $0,_param(PARAM_HAVE_VGA)
+ cmpb $0, _param(BVI_have_vga)
je 1f # Bail if there's no VGA
movw bootsym(boot_vid_mode), %ax # User selected video mode
cmpw $ASK_VGA, %ax # Bring up the menu
@@ -69,7 +50,7 @@ vid1: call store_edid
# Detect if we have CGA, MDA, EGA or VGA and pass it to the kernel.
basic_detect:
- movb $0, _param(PARAM_HAVE_VGA)
+ movb $0, _param(BVI_have_vga)
movb $0x12, %ah # Check EGA/VGA
movb $0x10, %bl
int $0x10
@@ -79,7 +60,7 @@ basic_detect:
int $0x10
cmpb $0x1a, %al # 1a means VGA...
jne basret # anything else is EGA.
- incb _param(PARAM_HAVE_VGA) # We've detected a VGA
+ incb _param(BVI_have_vga) # We've detected a VGA
basret: ret
# Store the video mode parameters for later usage by the kernel.
@@ -92,57 +73,57 @@ mode_params:
movb $0x03, %ah # Read cursor position
xorb %bh, %bh
int $0x10
- movw %dx, _param(PARAM_CURSOR_POS)
+ movw %dx, _param(BVI_cursor_pos)
movb $0x0f, %ah # Read page/mode/width
int $0x10
- movw %ax, _param(PARAM_VIDEO_MODE) # Video mode and screen width
+ movw %ax, _param(BVI_video_mode) # Video mode and screen width
movw %gs:(0x485), %ax # Font size
- movw %ax, _param(PARAM_FONT_POINTS) # (valid only on EGA/VGA)
+ movw %ax, _param(BVI_font_points) # (valid only on EGA/VGA)
movw bootsym(force_size), %ax # Forced size?
orw %ax, %ax
jz mopar1
- movb %ah, _param(PARAM_VIDEO_COLS)
- movb %al, _param(PARAM_VIDEO_LINES)
+ movb %ah, _param(BVI_video_cols)
+ movb %al, _param(BVI_video_lines)
ret
mopar1: movb %gs:(0x484), %al # On EGA/VGA, use the EGA+ BIOS
incb %al # location of max lines.
-mopar2: movb %al, _param(PARAM_VIDEO_LINES)
+mopar2: movb %al, _param(BVI_video_lines)
ret
# Fetching of VESA frame buffer parameters
mopar_gr:
movw $vesa_mode_info, %di
- movb $0x23, _param(PARAM_HAVE_VGA)
+ movb $0x23, _param(BVI_have_vga)
movw 16(%di), %ax
- movw %ax, _param(PARAM_LFB_LINELENGTH)
+ movw %ax, _param(BVI_lfb_linelength)
movw 18(%di), %ax
- movw %ax, _param(PARAM_LFB_WIDTH)
+ movw %ax, _param(BVI_lfb_width)
movw 20(%di), %ax
- movw %ax, _param(PARAM_LFB_HEIGHT)
+ movw %ax, _param(BVI_lfb_height)
movzbw 25(%di), %ax
- movw %ax, _param(PARAM_LFB_DEPTH)
+ movw %ax, _param(BVI_lfb_depth)
movl 40(%di), %eax
- movl %eax, _param(PARAM_LFB_BASE)
+ movl %eax, _param(BVI_lfb_base)
movl 31(%di), %eax
- movl %eax, _param(PARAM_LFB_COLORS)
+ movl %eax, _param(BVI_lfb_colors)
movl 35(%di), %eax
- movl %eax, _param(PARAM_LFB_COLORS+4)
+ movl %eax, _param(BVI_lfb_colors+4)
movw 0(%di), %ax
- movw %ax, _param(PARAM_VESA_ATTRIB)
+ movw %ax, _param(BVI_vesa_attrib)
# get video mem size
movw $vesa_glob_info, %di
movzwl 18(%di), %eax
- movl %eax, _param(PARAM_LFB_SIZE)
+ movl %eax, _param(BVI_lfb_size)
# store mode capabilities
movl 10(%di), %eax
- movl %eax, _param(PARAM_CAPABILITIES)
+ movl %eax, _param(BVI_capabilities)
# switching the DAC to 8-bit is for <= 8 bpp only
- cmpw $8, _param(PARAM_LFB_DEPTH)
+ cmpw $8, _param(BVI_lfb_depth)
jg dac_done
# get DAC switching capability
@@ -160,16 +141,16 @@ mopar_gr:
dac_set:
# set color size to DAC size
movzbw bootsym(dac_size), %ax
- movb %al, _param(PARAM_LFB_COLORS+0)
- movb %al, _param(PARAM_LFB_COLORS+2)
- movb %al, _param(PARAM_LFB_COLORS+4)
- movb %al, _param(PARAM_LFB_COLORS+6)
+ movb %al, _param(BVI_lfb_colors + 0)
+ movb %al, _param(BVI_lfb_colors + 2)
+ movb %al, _param(BVI_lfb_colors + 4)
+ movb %al, _param(BVI_lfb_colors + 6)
# set color offsets to 0
- movb %ah, _param(PARAM_LFB_COLORS+1)
- movb %ah, _param(PARAM_LFB_COLORS+3)
- movb %ah, _param(PARAM_LFB_COLORS+5)
- movb %ah, _param(PARAM_LFB_COLORS+7)
+ movb %ah, _param(BVI_lfb_colors + 1)
+ movb %ah, _param(BVI_lfb_colors + 3)
+ movb %ah, _param(BVI_lfb_colors + 5)
+ movb %ah, _param(BVI_lfb_colors + 7)
dac_done:
# get protected mode interface information
@@ -180,8 +161,8 @@ dac_done:
cmp $0x004f, %ax
jnz no_pm
- movw %es, _param(PARAM_VESAPM_SEG)
- movw %di, _param(PARAM_VESAPM_OFF)
+ movw %es, _param(BVI_vesapm_seg)
+ movw %di, _param(BVI_vesapm_off)
no_pm: pushw %ds
popw %es
@@ -1018,7 +999,7 @@ GLOBAL(boot_vid_info)
.byte 80, 25 /* 80x25 */
.byte 1 /* isVGA */
.word 16 /* 8x16 font */
- .fill 0x28,1,0
+ .space BVI_size - (. - boot_vid_info)
GLOBAL(boot_edid_info)
.fill 128,1,0x13
GLOBAL(boot_edid_caps)
diff --git a/xen/arch/x86/x86_64/asm-offsets.c b/xen/arch/x86/x86_64/asm-offsets.c
index 3fe21c21b95c..630bdc39451d 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -16,6 +16,10 @@
#include <xen/multiboot.h>
#include <xen/multiboot2.h>
+#ifdef CONFIG_VIDEO
+# include "../boot/video.h"
+#endif
+
#define DEFINE(_sym, _val) \
asm volatile ( "\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\""\
:: "i" (_val) )
@@ -208,4 +212,26 @@ void __dummy__(void)
OFFSET(DOMAIN_vm_assist, struct domain, vm_assist);
BLANK();
+
+#ifdef CONFIG_VIDEO
+ OFFSET(BVI_cursor_pos, struct boot_video_info, orig_x);
+ OFFSET(BVI_video_mode, struct boot_video_info, orig_video_mode);
+ OFFSET(BVI_video_cols, struct boot_video_info, orig_video_cols);
+ OFFSET(BVI_video_lines, struct boot_video_info, orig_video_lines);
+ OFFSET(BVI_have_vga, struct boot_video_info, orig_video_isVGA);
+ OFFSET(BVI_font_points, struct boot_video_info, orig_video_points);
+ OFFSET(BVI_capabilities, struct boot_video_info, capabilities);
+ OFFSET(BVI_lfb_linelength, struct boot_video_info, lfb_linelength);
+ OFFSET(BVI_lfb_width, struct boot_video_info, lfb_width);
+ OFFSET(BVI_lfb_height, struct boot_video_info, lfb_height);
+ OFFSET(BVI_lfb_depth, struct boot_video_info, lfb_depth);
+ OFFSET(BVI_lfb_base, struct boot_video_info, lfb_base);
+ OFFSET(BVI_lfb_size, struct boot_video_info, lfb_size);
+ OFFSET(BVI_lfb_colors, struct boot_video_info, colors);
+ OFFSET(BVI_vesapm_seg, struct boot_video_info, vesapm.seg);
+ OFFSET(BVI_vesapm_off, struct boot_video_info, vesapm.off);
+ OFFSET(BVI_vesa_attrib, struct boot_video_info, vesa_attrib);
+ DEFINE(BVI_size, sizeof(struct boot_video_info));
+ BLANK();
+#endif /* CONFIG_VIDEO */
}
--
2.44.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/2] x86/pvh: zero VGA information
2024-04-22 9:52 [PATCH v2 0/2] x86/pvh: fix VGA reporting when booted as a PVH guest Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 1/2] x86/video: add boot_video_info offset generation to asm-offsets Roger Pau Monne
@ 2024-04-22 9:52 ` Roger Pau Monne
2024-04-22 10:27 ` Jan Beulich
1 sibling, 1 reply; 4+ messages in thread
From: Roger Pau Monne @ 2024-04-22 9:52 UTC (permalink / raw
To: xen-devel; +Cc: Roger Pau Monne, Jan Beulich, Andrew Cooper
PVH guests skip real mode VGA detection, and never have a VGA available, hence
the default VGA selection is not applicable, and at worse can cause confusion
when parsing Xen boot log.
Zero the boot_vid_info structure when Xen is booted from the PVH entry point.
This fixes Xen incorrectly reporting:
(XEN) Video information:
(XEN) VGA is text mode 80x25, font 8x16
When booted as a PVH guest.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
xen/arch/x86/boot/video.h | 2 ++
xen/arch/x86/guest/xen/pvh-boot.c | 9 +++++++++
xen/arch/x86/setup.c | 1 -
3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/boot/video.h b/xen/arch/x86/boot/video.h
index 6a7775d24292..1203515f9e5b 100644
--- a/xen/arch/x86/boot/video.h
+++ b/xen/arch/x86/boot/video.h
@@ -67,6 +67,8 @@ struct boot_video_info {
} vesapm;
uint16_t vesa_attrib; /* 0x28 */
};
+
+extern struct boot_video_info boot_vid_info;
#endif /* __ASSEMBLY__ */
#endif /* __BOOT_VIDEO_H__ */
diff --git a/xen/arch/x86/guest/xen/pvh-boot.c b/xen/arch/x86/guest/xen/pvh-boot.c
index 9cbe87b61bdd..cc57ab2cbcde 100644
--- a/xen/arch/x86/guest/xen/pvh-boot.c
+++ b/xen/arch/x86/guest/xen/pvh-boot.c
@@ -15,6 +15,10 @@
#include <public/arch-x86/hvm/start_info.h>
+#ifdef CONFIG_VIDEO
+# include "../../boot/video.h"
+#endif
+
/* Initialised in head.S, before .bss is zeroed. */
bool __initdata pvh_boot;
uint32_t __initdata pvh_start_info_pa;
@@ -95,6 +99,11 @@ void __init pvh_init(multiboot_info_t **mbi, module_t **mod)
ASSERT(xen_guest);
get_memory_map();
+
+#ifdef CONFIG_VIDEO
+ /* No VGA available when booted from the PVH entry point. */
+ memset(&bootsym(boot_vid_info), 0, sizeof(boot_vid_info));
+#endif
}
void __init pvh_print_info(void)
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 86cd8b999774..449a3476531e 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -646,7 +646,6 @@ static struct e820map __initdata boot_e820;
#ifdef CONFIG_VIDEO
# include "boot/video.h"
-extern struct boot_video_info boot_vid_info;
#endif
static void __init parse_video_info(void)
--
2.44.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/2] x86/pvh: zero VGA information
2024-04-22 9:52 ` [PATCH v2 2/2] x86/pvh: zero VGA information Roger Pau Monne
@ 2024-04-22 10:27 ` Jan Beulich
0 siblings, 0 replies; 4+ messages in thread
From: Jan Beulich @ 2024-04-22 10:27 UTC (permalink / raw
To: Roger Pau Monne; +Cc: Andrew Cooper, xen-devel
On 22.04.2024 11:52, Roger Pau Monne wrote:
> PVH guests skip real mode VGA detection, and never have a VGA available, hence
> the default VGA selection is not applicable, and at worse can cause confusion
> when parsing Xen boot log.
>
> Zero the boot_vid_info structure when Xen is booted from the PVH entry point.
>
> This fixes Xen incorrectly reporting:
>
> (XEN) Video information:
> (XEN) VGA is text mode 80x25, font 8x16
>
> When booted as a PVH guest.
>
> Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-04-22 10:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2024-04-22 9:52 [PATCH v2 0/2] x86/pvh: fix VGA reporting when booted as a PVH guest Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 1/2] x86/video: add boot_video_info offset generation to asm-offsets Roger Pau Monne
2024-04-22 9:52 ` [PATCH v2 2/2] x86/pvh: zero VGA information Roger Pau Monne
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