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[Qemu-stable] [PATCH 84/88] linuxboot: fix loading old kernels
From: |
Michael Roth |
Subject: |
[Qemu-stable] [PATCH 84/88] linuxboot: fix loading old kernels |
Date: |
Thu, 8 Jan 2015 11:34:28 -0600 |
From: Paolo Bonzini <address@hidden>
Old kernels that used high memory only allowed the initrd to be in the
first 896MB of memory. If you load the initrd above, they complain
that "initrd extends beyond end of memory".
In order to fix this, while not breaking machines with small amounts
of memory fixed by cdebec5 (linuxboot: compute initrd loading address,
2014-10-06), we need to distinguish two cases. If pc.c placed the
initrd at end of memory, use the new algorithm based on the e801
memory map. If instead pc.c placed the initrd at the maximum address
specified by the bzImage, leave it there.
The only interesting part is that the low-memory info block is now
loaded very early, in real mode, and thus the 32-bit address has
to be converted into a real mode segment. The initrd address is
also patched in the info block before entering real mode, it is
simpler that way.
This fixes booting the RHEL4.8 32-bit installation image with 1GB
of RAM.
Cc: address@hidden
Cc: address@hidden
Cc: address@hidden
Signed-off-by: Paolo Bonzini <address@hidden>
(cherry picked from commit 269e2358492b674c50160553d037702e916b9f1b)
Signed-off-by: Michael Roth <address@hidden>
---
pc-bios/linuxboot.bin | Bin 1024 -> 1024 bytes
pc-bios/optionrom/linuxboot.S | 37 +++++++++++++++++++++++++++----------
2 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/pc-bios/linuxboot.bin b/pc-bios/linuxboot.bin
index
130103fb739228a6869aaf1b174b9d20c13378fc..923d1796fbc58f1a836c160be533d1cf697b7511
100644
GIT binary patch
delta 142
zcmZqRXyBNj#iGKj$vjbS<zxpYS+0XGSo#j68UEiPKG~5;c5)+=ut=jF8xu2AF_&7}
zaW);M|address@hidden|1U|HcrA)eEv?f|address@hidden
o^JH&address@hidden<!fu0k62VPqJWthB%=`*7=0A&s>tpET3
delta 89
zcmV-f0H*(d2!IHXDg?v=$pVossgsWZS(EMo83L>VlL-PJ0%li}!2uqVMgp}0xE7KA
v9R$Z_iNlfnG8kuOkAoNj003sV000004<f*f$d172nf;Rt1M`zm17HDDa`7NG
diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
index 5bc0af0..ba821ab 100644
--- a/pc-bios/optionrom/linuxboot.S
+++ b/pc-bios/optionrom/linuxboot.S
@@ -76,7 +76,31 @@ boot_kernel:
copy_kernel:
- /* Compute initrd address */
+ /* Read info block in low memory (0x10000 or 0x90000) */
+ read_fw FW_CFG_SETUP_ADDR
+ shr $4, %eax
+ mov %eax, %es
+ xor %edi, %edi
+ read_fw_blob_addr32_edi(FW_CFG_SETUP)
+
+ cmpw $0x203, %es:0x206 // if protocol >= 0x203
+ jae 1f // have initrd_max
+ movl $0x37ffffff, %es:0x22c // else assume 0x37ffffff
+1:
+
+ /* Check if using kernel-specified initrd address */
+ read_fw FW_CFG_INITRD_ADDR
+ mov %eax, %edi // (load_kernel wants it in %edi)
+ read_fw FW_CFG_INITRD_SIZE // find end of initrd
+ add %edi, %eax
+ xor %es:0x22c, %eax // if it matches es:0x22c
+ and $-4096, %eax // (apart from padding for page)
+ jz load_kernel // then initrd is not at top
+ // of memory
+
+ /* pc.c placed the initrd at end of memory. Compute a better
+ * initrd address based on e801 data.
+ */
mov $0xe801, %ax
xor %cx, %cx
xor %dx, %dx
@@ -107,7 +131,9 @@ copy_kernel:
read_fw FW_CFG_INITRD_SIZE
subl %eax, %edi
andl $-4096, %edi /* EDI = start of initrd */
+ movl %edi, %es:0x218 /* put it in the header */
+load_kernel:
/* 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. */
@@ -139,19 +165,10 @@ 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_CMDLINE)
- 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
mov %eax, %cr0
--
1.9.1
- [Qemu-stable] [PATCH 73/88] iotests: Only kill NBD server if it runs, (continued)
- [Qemu-stable] [PATCH 73/88] iotests: Only kill NBD server if it runs, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 74/88] iotests: Add test for unsupported image creation, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 70/88] block: Check create_opts before image creation, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 76/88] qcow2: Flushing the caches in qcow2_close may fail, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 79/88] block migration: fix return value, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 77/88] qcow2: Respect bdrv_truncate() error, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 78/88] block/raw-posix: Fix ret in raw_open_common(), Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 80/88] qcow2: Fix header extension size check, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 82/88] block: Don't probe for unknown backing file format, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 83/88] linuxboot: compute initrd loading address, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 84/88] linuxboot: fix loading old kernels,
Michael Roth <=
- [Qemu-stable] [PATCH 87/88] target-xtensa: test cross-page opcode, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 85/88] audio: Don't free hw resources until after hw backend is stopped, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 75/88] qcow2: Prevent numerical overflow, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 81/88] qcow2.py: Add required padding for header extensions, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 86/88] target-xtensa: fix translation for opcodes crossing page boundary, Michael Roth, 2015/01/08
- [Qemu-stable] [PATCH 88/88] pc: acpi: mark all possible CPUs as enabled in SRAT, Michael Roth, 2015/01/08
- Re: [Qemu-stable] [Qemu-devel] Patch Round-up for stable 2.1.3, freeze on 2015-01-14, Marcel Apfelbaum, 2015/01/09