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[Qemu-devel] [PATCH 83/88] linuxboot: compute initrd loading address
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 83/88] linuxboot: compute initrd loading address |
Date: |
Thu, 8 Jan 2015 11:34:27 -0600 |
From: Paolo Bonzini <address@hidden>
Even though hw/i386/pc.c tries to compute a valid loading address for the
initrd, close to the top of RAM, this does not take into account other
data that is malloced into that memory by SeaBIOS.
Luckily we can easily look at the memory map to find out how much memory is
used up there. This patch places the initrd in the first four gigabytes,
below the first hole (as returned by INT 15h, AX=e801h).
Without this patch:
[ 0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[ 0.000000] RAMDISK: [mem 0x0710a000-0x07fd7fff]
With this patch:
[ 0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[ 0.000000] RAMDISK: [mem 0x07112000-0x07fdffff]
So linuxboot is able to use the 64k that were added as padding for
QEMU <= 2.1.
Acked-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
(cherry picked from commit cdebec5e40bd0af82da0659f37af85ee2aa2c9d1)
Signed-off-by: Michael Roth <address@hidden>
---
pc-bios/linuxboot.bin | Bin 1024 -> 1024 bytes
pc-bios/optionrom/linuxboot.S | 47 ++++++++++++++++++++++++++++++++++++++----
pc-bios/optionrom/optionrom.h | 21 ++++++++++++++++---
3 files changed, 61 insertions(+), 7 deletions(-)
diff --git a/pc-bios/linuxboot.bin b/pc-bios/linuxboot.bin
index
e7c36694f997c3c34f7f4af3c2923bd2ef6094e7..130103fb739228a6869aaf1b174b9d20c13378fc
100644
GIT binary patch
delta 168
zcmZqRXyBNj#e9V6<address@hidden|bXJt}WGM&drBas8gPpg4G+*OE29`Ab?LX5F
zKIeMP(|Cx15y<-m<Oxh}WRz3ZJf7D0oZ-X&|7o31)0*E19C!O5&XCq~0;uRf+QA1b
zX{>7|eo$aa3kRw;nk>i|IC(Q;0c%?4;address@hidden;0)C|f
SJtz7Oyqvi?nJI*kF&F^X7ev$m
delta 107
address@hidden|`VlnOD22!$<yBUQi
zzh^99+93|&DjwV+!H~8~fR%ya{VqY)Kk1)y(snQa0l(6Lo)disUOwEsnkj^F@&_gl
G#(w~}wj;0r
diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
index 748c831..5bc0af0 100644
--- a/pc-bios/optionrom/linuxboot.S
+++ b/pc-bios/optionrom/linuxboot.S
@@ -76,14 +76,45 @@ boot_kernel:
copy_kernel:
+ /* Compute initrd address */
+ mov $0xe801, %ax
+ xor %cx, %cx
+ xor %dx, %dx
+ int $0x15
+
+ /* Output could be in AX/BX or CX/DX */
+ or %cx, %cx
+ jnz 1f
+ or %dx, %dx
+ jnz 1f
+ mov %ax, %cx
+ mov %bx, %dx
+1:
+
+ or %dx, %dx
+ jnz 2f
+ addw $1024, %cx /* add 1 MB */
+ movzwl %cx, %edi
+ shll $10, %edi /* convert to bytes */
+ jmp 3f
+
+2:
+ addw $16777216 >> 16, %dx /* add 16 MB */
+ movzwl %dx, %edi
+ shll $16, %edi /* convert to bytes */
+
+3:
+ read_fw FW_CFG_INITRD_SIZE
+ subl %eax, %edi
+ andl $-4096, %edi /* EDI = start of initrd */
/* We need to load the kernel into memory we can't access in 16 bit
mode, so let's get into 32 bit mode, write the kernel and jump
back again. */
/* Reserve space on the stack for our GDT descriptor. */
- mov %esp, %ebp
- sub $16, %esp
+ mov %esp, %ebp
+ sub $16, %esp
/* Now create the GDT descriptor */
movw $((3 * 8) - 1), -16(%bp)
@@ -108,10 +139,18 @@ copy_kernel:
/* We're now running in 16-bit CS, but 32-bit ES! */
/* Load kernel and initrd */
+ pushl %edi
+ read_fw_blob_addr32_edi(FW_CFG_INITRD)
read_fw_blob_addr32(FW_CFG_KERNEL)
- read_fw_blob_addr32(FW_CFG_INITRD)
read_fw_blob_addr32(FW_CFG_CMDLINE)
- read_fw_blob_addr32(FW_CFG_SETUP)
+
+ read_fw FW_CFG_SETUP_ADDR
+ mov %eax, %edi
+ mov %eax, %ebx
+ read_fw_blob_addr32_edi(FW_CFG_SETUP)
+
+ /* Update the header with the initrd address we chose above */
+ popl %es:0x218(%ebx)
/* And now jump into Linux! */
mov $0, %eax
diff --git a/pc-bios/optionrom/optionrom.h b/pc-bios/optionrom/optionrom.h
index ce43608..f1a9021 100644
--- a/pc-bios/optionrom/optionrom.h
+++ b/pc-bios/optionrom/optionrom.h
@@ -51,8 +51,6 @@
.endm
#define read_fw_blob_pre(var) \
- read_fw var ## _ADDR; \
- mov %eax, %edi; \
read_fw var ## _SIZE; \
mov %eax, %ecx; \
mov $var ## _DATA, %ax; \
@@ -68,6 +66,8 @@
* Clobbers: %eax, %edx, %es, %ecx, %edi
*/
#define read_fw_blob(var) \
+ read_fw var ## _ADDR; \
+ mov %eax, %edi; \
read_fw_blob_pre(var); \
/* old as(1) doesn't like this insn so emit the bytes instead: \
rep insb (%dx), %es:(%edi); \
@@ -80,7 +80,22 @@
*
* Clobbers: %eax, %edx, %es, %ecx, %edi
*/
-#define read_fw_blob_addr32(var) \
+#define read_fw_blob_addr32(var) \
+ read_fw var ## _ADDR; \
+ mov %eax, %edi; \
+ read_fw_blob_pre(var); \
+ /* old as(1) doesn't like this insn so emit the bytes instead: \
+ addr32 rep insb (%dx), %es:(%edi); \
+ */ \
+ .dc.b 0x67,0xf3,0x6c
+
+/*
+ * Read a blob from the fw_cfg device in forced addr32 mode, address is in
%edi.
+ * Requires _SIZE and _DATA values for the parameter.
+ *
+ * Clobbers: %eax, %edx, %edi, %es, %ecx
+ */
+#define read_fw_blob_addr32_edi(var) \
read_fw_blob_pre(var); \
/* old as(1) doesn't like this insn so emit the bytes instead: \
addr32 rep insb (%dx), %es:(%edi); \
--
1.9.1
- [Qemu-devel] [PATCH 73/88] iotests: Only kill NBD server if it runs, (continued)
- [Qemu-devel] [PATCH 73/88] iotests: Only kill NBD server if it runs, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 69/88] block/nfs: Add create_opts, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 79/88] block migration: fix return value, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 71/88] qemu-img: Check create_opts before image creation, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 72/88] qemu-img: Check create_opts before image amendment, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 74/88] iotests: Add test for unsupported image creation, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 77/88] qcow2: Respect bdrv_truncate() error, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 80/88] qcow2: Fix header extension size check, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 76/88] qcow2: Flushing the caches in qcow2_close may fail, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 84/88] linuxboot: fix loading old kernels, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 83/88] linuxboot: compute initrd loading address,
Michael Roth <=
- [Qemu-devel] [PATCH 82/88] block: Don't probe for unknown backing file format, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 85/88] audio: Don't free hw resources until after hw backend is stopped, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 78/88] block/raw-posix: Fix ret in raw_open_common(), Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 75/88] qcow2: Prevent numerical overflow, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 81/88] qcow2.py: Add required padding for header extensions, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 86/88] target-xtensa: fix translation for opcodes crossing page boundary, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 88/88] pc: acpi: mark all possible CPUs as enabled in SRAT, Michael Roth, 2015/01/08
- [Qemu-devel] [PATCH 87/88] target-xtensa: test cross-page opcode, Michael Roth, 2015/01/08
- Re: [Qemu-devel] Patch Round-up for stable 2.1.3, freeze on 2015-01-14, Marcel Apfelbaum, 2015/01/09