linux-kernel - Re: [tip:x86/boot] x86/boot: Early parse RSDP and save it in boot

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Date:   Mon, 11 Feb 2019 17:30:33 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Guenter Roeck <linux@...ck-us.net>
CC:     <tglx@...utronix.de>, <linux-kernel@...r.kernel.org>,
        <kirill.shutemov@...ux.intel.com>, <bp@...e.de>,
        <mingo@...hat.com>, <thomas.lendacky@....com>,
        <yamada.masahiro@...ionext.com>, <caoj.fnst@...fujitsu.com>,
        <jgross@...e.com>, <mingo@...nel.org>, <keescook@...omium.org>,
        <x86@...nel.org>, <hpa@...or.com>,
        <linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/boot] x86/boot: Early parse RSDP and save it in
 boot_params

On Fri, Feb 08, 2019 at 11:02:48AM -0800, Guenter Roeck wrote:
>Hi,
>
>On Fri, Feb 01, 2019 at 03:01:11AM -0800, tip-bot for Chao Fan wrote:
>> Commit-ID:  3a63f70bf4c3a17f5d9c9bf3bc3288a23bdfefce
>> Gitweb:     https://git.kernel.org/tip/3a63f70bf4c3a17f5d9c9bf3bc3288a23bdfefce
>> Author:     Chao Fan <fanc.fnst@...fujitsu.com>
>> AuthorDate: Wed, 23 Jan 2019 19:08:48 +0800
>> Committer:  Borislav Petkov <bp@...e.de>
>> CommitDate: Fri, 1 Feb 2019 11:52:55 +0100
>> 
>> x86/boot: Early parse RSDP and save it in boot_params
>> 
>> The RSDP is needed by KASLR so parse it early and save it in
>> boot_params.acpi_rsdp_addr, before KASLR setup runs.
>> 
>> RSDP is needed by other kernel facilities so have the parsing code
>> built-in instead of a long "depends on" line in Kconfig.
>> 
>>  [ bp:
>>     - Trim commit message and comments
>>     - Add CONFIG_ACPI dependency in the Makefile
>>     - Move ->acpi_rsdp_addr assignment with the rest of boot_params massaging in extract_kernel().
>>  ]
>> 
>
>This patch causes x86_64 boots with efi32 bios to crash early and hard
>(before any console output is seen).
>
>Sample qemu command line:
>
>qemu-system-x86_64 -kernel arch/x86/boot/bzImage -M q35 -cpu SandyBridge \
>	-no-reboot -snapshot -smp 4 \
>	-bios OVMF-pure-efi-32.fd \
>	-m 1G \
>	-usb -device usb-storage,drive=d0 \
>	-drive file=rootfs.squashfs,if=none,id=d0,format=raw \
>	--append 'earlycon=uart8250,io,0x3f8,9600n8 root=/dev/sda rootwait panic=-1 console=ttyS0' \
>	-nographic
>
>This is with qemu 3.1, though details other than "-bios OVMF-pure-efi-32.fd"
>don't really matter.

Yes, I download your ovmf file in linux-build-test/rootfs/firmware/ from
your link. There are two files, efi32 and efi64. Then I try to run:

BIOS=/usr/share/edk2/ovmf/OVMF-pure-efi-32.fd
qemu-system-x86_64 \
-bios $BIOS \
-cdrom /var/lib/libvirt/images/iso/Fedora-Workstation-Live-x86_64-29-1.2.iso \
-hda /var/lib/libvirt/images/fedora-efi32.qcow2 \
-enable-kvm \
-m 5G \
-serial stdio

It can't boot, but if I changed as:
BIOS=/usr/share/edk2/ovmf/OVMF-pure-efi-64.fd

Then the machine booted. So I am not sure how to use this
OVMF-pure-efi-32.fd. If there is somethins wrong in my understand,
please let me know.

Thanks,
Chao Fan

>
>Files used above are available from https://github.com/groeck/linux-build-test/.
>
>The patch can not be reverted alone, but
>
>Revert "x86/boot/KASLR: Limit KASLR to extract the kernel in immovable memory only"
>Revert "x86/boot: Parse SRAT table and count immovable memory regions"
>Revert "x86/boot: Early parse RSDP and save it in boot_params"
>
>fixes the problem.
>
>Bisect log attached below.
>
>Guenter
>
>---
># bad: [a46228f6598a191e25ca160870f20c3cd1743d13] Add linux-next specific files for 20190208
># good: [8834f5600cf3c8db365e18a3d5cac2c2780c81e5] Linux 5.0-rc5
>git bisect start 'HEAD' 'v5.0-rc5'
># good: [d5ee02f33ec5ade9c9afb9d45bfc4f5cb1375e58] Merge remote-tracking branch 'spi-nor/spi-nor/next'
>git bisect good d5ee02f33ec5ade9c9afb9d45bfc4f5cb1375e58
># good: [f34bff29873986d260d7a491fb6f543d12fbe7cd] Merge remote-tracking branch 'devicetree/for-next'
>git bisect good f34bff29873986d260d7a491fb6f543d12fbe7cd
># bad: [68182cb929ec6a676655887cbfb12b09662c1e5b] Merge remote-tracking branch 'icc/icc-next'
>git bisect bad 68182cb929ec6a676655887cbfb12b09662c1e5b
># bad: [0a5c6189664123753c298d90dec3a5a6b907f06f] Merge remote-tracking branch 'driver-core/driver-core-next'
>git bisect bad 0a5c6189664123753c298d90dec3a5a6b907f06f
># bad: [e2a43b09bfc24369719437b5f8f703c5d7003af2] Merge remote-tracking branch 'tip/auto-latest'
>git bisect bad e2a43b09bfc24369719437b5f8f703c5d7003af2
># good: [ba1ef96ac73d2a9851dc64d0a991ac8699aa6a22] Merge branch 'timers/core'
>git bisect good ba1ef96ac73d2a9851dc64d0a991ac8699aa6a22
># good: [473a78a7bbeb7c77b81b596095f59ce4fbbd49dc] spi-atmel: support inter-word delay
>git bisect good 473a78a7bbeb7c77b81b596095f59ce4fbbd49dc
># bad: [132dc31173c99bd252f6a54e3a9fba90f7417a43] Merge branch 'x86/cleanups'
>git bisect bad 132dc31173c99bd252f6a54e3a9fba90f7417a43
># bad: [6eb09d138a331121740a4cf7458ab317979d9a17] Merge branch 'x86/boot'
>git bisect bad 6eb09d138a331121740a4cf7458ab317979d9a17
># good: [e2c403557ebbcd1f0052e1ae51cfaff596cf259d] Merge branch 'x86/asm'
>git bisect good e2c403557ebbcd1f0052e1ae51cfaff596cf259d
># good: [33f0df8d843deb9ec24116dcd79a40ca0ea8e8a9] x86/boot: Search for RSDP in the EFI tables
>git bisect good 33f0df8d843deb9ec24116dcd79a40ca0ea8e8a9
># bad: [3a63f70bf4c3a17f5d9c9bf3bc3288a23bdfefce] x86/boot: Early parse RSDP and save it in boot_params
>git bisect bad 3a63f70bf4c3a17f5d9c9bf3bc3288a23bdfefce
># good: [93a209aaaad495d7d0bc9b6186a4495934f70402] x86/boot: Search for RSDP in memory
>git bisect good 93a209aaaad495d7d0bc9b6186a4495934f70402
># first bad commit: [3a63f70bf4c3a17f5d9c9bf3bc3288a23bdfefce] x86/boot: Early parse RSDP and save it in boot_params
>
>