Re: [PATCH v7 0/6] tpm: Preserve TPM measurement log across kexec (ppc64)

Coiby Xu
2022-08-15T06:50:56Z

I can confirm this patch set fixes an issue that guest kdump kernel
crashes on POWER9 host by applying it to 5.19.1 (there is a conflict
when applying this patch set to latest kernel i.e. 6.0.0-rc1).

Tested-by: Coiby Xu <coxu@redhat.com>

Previously, the issue can be reproduced as follows,

1. revert commit 7c5ed82b800d ("powerpc: Set crashkernel offset to mid
of RMA region") which masks the issue
2. build & boot the kernel with crashkernel=512M
3. load kdump kernel and trigger kernel crash,
[ 4.209792] Oops: Kernel access of bad area, sig: 11 [#1]
[ 4.210373] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
[ 4.210985] Modules linked in:
[ 4.211570] CPU: 12 PID: 1 Comm: swapper/12 Not tainted 6.0.0-rc1+ #3
[ 4.212204] NIP: c0000000080a6540 LR: c00000000840c630 CTR: 0000000000000800
[ 4.212871] REGS: c00000000e66b130 TRAP: 0300 Not tainted (6.0.0-rc1+)
[ 4.213529] MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24000280 XER: 0000005b
[ 4.214242] CFAR: c0000000080a6528 DAR: c00000002ffb0000 DSISR: 40000000 IRQMASK: 0
[ 4.214242] GPR00: 000000000e000000 c00000000e66b3d0 c00000000aa69a00 c0000000117c0000
[ 4.214242] GPR04: c00000002ffb0000 0000000000040000 0000000000000800 03fffffffee84000
[ 4.214242] GPR08: 0000000080000000 0000000000000010 0000000000000020 0000000000000030
[ 4.214242] GPR12: 0000000000000040 c00000000ad61000 0000000000000050 0000000000000060
[ 4.214242] GPR16: 0000000000000070 0000000000000000 0000000000000000 0000000000000000
[ 4.214242] GPR20: 0000000000000000 0000000000000000 c000000008f7ebd8 c00000000e418420
[ 4.214242] GPR24: c00000000ad3c389 c000000008f7ed60 c00000000ecc9000 c000000011271848
[ 4.214242] GPR28: c000000027fcee5c c00000002ffb0000 0000000000040000 c0000000117c0000
[ 4.220176] NIP [c0000000080a6540] memcpy_power7+0x400/0x7d0
[ 4.220808] LR [c00000000840c630] kmemdup+0x50/0x80
[ 4.221428] Call Trace:
[ 4.222006] [c00000000e66b3d0] [c0000000080a63b4] memcpy_power7+0x274/0x7d0 (unreliable)
[ 4.222662] [c00000000e66b4d0] [c00000000840c630] kmemdup+0x50/0x80
[ 4.223293] [c00000000e66b510] [c000000008973ee0] tpm_read_log_of+0x110/0x1f0
[ 4.223929] [c00000000e66b5a0] [c000000008973020] tpm_bios_log_setup+0x80/0x250
[ 4.224552] [c00000000e66b630] [c00000000896b938] tpm_chip_register.part.0+0x38/0x2a0
[ 4.225170] [c00000000e66b6b0] [c000000008979a80] tpm_ibmvtpm_probe+0x530/0x7d0
[ 4.225777] [c00000000e66b790] [c0000000081055e4] vio_bus_probe+0x94/0x150
[ 4.226366] [c00000000e66b7e0] [c0000000089936d4] really_probe+0x104/0x550
[ 4.226947] [c00000000e66b860] [c000000008993bd4] __driver_probe_device+0xb4/0x240
[ 4.227560] [c00000000e66b8e0] [c000000008993db4] driver_probe_device+0x54/0x130
[ 4.228159] [c00000000e66b920] [c000000008994a88] __driver_attach+0x128/0x2d0
[ 4.228748] [c00000000e66b9a0] [c00000000898fcf8] bus_for_each_dev+0xa8/0x130
[ 4.229325] [c00000000e66ba00] [c000000008992bd4] driver_attach+0x34/0x50
[ 4.229887] [c00000000e66ba20] [c0000000089922d8] bus_add_driver+0x218/0x300
[ 4.230453] [c00000000e66bab0] [c000000008995f94] driver_register+0xb4/0x1c0
[ 4.231012] [c00000000e66bb20] [c000000008103fb0] __vio_register_driver+0x80/0xf0
[ 4.231569] [c00000000e66bba0] [c00000000a06807c] ibmvtpm_module_init+0x34/0x48
[ 4.232119] [c00000000e66bbc0] [c000000008011c14] do_one_initcall+0x64/0x300
[ 4.232664] [c00000000e66bca0] [c00000000a0053f0] do_initcalls+0x13c/0x190
[ 4.233183] [c00000000e66bd50] [c00000000a00570c] kernel_init_freeable+0x22c/0x2a0
[ 4.233706] [c00000000e66bdb0] [c000000008012240] kernel_init+0x30/0x1a0
[ 4.234204] [c00000000e66be10] [c00000000800ca54] ret_from_kernel_thread+0x5c/0x64
[ 4.234721] Instruction dump:
[ 4.235191] fa010080 39800040 39c00050 39e00060 3a000070 7cc903a6 48000018 60000000
[ 4.235738] 60000000 60000000 60000000 60000000 <7ce020ce> 7cc448ce 7ca450ce 7c8458ce
[ 4.236302] ---[ end trace 0000000000000000 ]---

On Fri, Aug 12, 2022 at 12:42:59PM -0400, Stefan Berger wrote:
>The of-tree subsystem does not currently preserve the IBM vTPM 1.2 and
>vTPM 2.0 measurement logs across a kexec on PowerVM and PowerKVM. This
>series fixes this for the kexec_file_load() syscall using the flattened
>device tree (fdt) to carry the TPM measurement log's buffer across kexec.
>
> Stefan
>
>v7:
> - Added Nageswara's Tested-by tags
> - Added back original comment to inline function and removed Jarkko's R-b tag
>
>v6:
> - Add __init to get_kexec_buffer as suggested by Jonathan
> - Fixed issue detected by kernel test robot
>
>v5:
> - Rebased on 1 more patch that would otherwise create merge conflicts
>
>v4:
> - Rebased on 2 patches that would otherwise create merge conflicts;
> posting these patches in this series with several tags removed so
> krobot can test the series already
> - Changes to individual patches documented in patch descripitons
>
>v3:
> - Moved TPM Open Firmware related function to drivers/char/tpm/eventlog/tpm_of.c
>
>v2:
> - rearranged patches
> - fixed compilation issues for x86
>
>
>Jonathan McDowell (1):
> x86/kexec: Carry forward IMA measurement log on kexec
>
>Palmer Dabbelt (1):
> drivers: of: kexec ima: Support 32-bit platforms
>
>Stefan Berger (3):
> tpm: of: Make of-tree specific function commonly available
> of: kexec: Refactor IMA buffer related functions to make them reusable
> tpm/kexec: Duplicate TPM measurement log in of-tree for kexec
>
>Vaibhav Jain (1):
> of: check previous kernel's ima-kexec-buffer against memory bounds
>
> arch/x86/Kconfig | 1 +
> arch/x86/include/uapi/asm/bootparam.h | 9 +
> arch/x86/kernel/e820.c | 6 +-
> arch/x86/kernel/kexec-bzimage64.c | 42 +++-
> arch/x86/kernel/setup.c | 63 +++++
> drivers/char/tpm/eventlog/of.c | 31 +--
> drivers/of/kexec.c | 342 ++++++++++++++++++++++----
> include/linux/ima.h | 5 +
> include/linux/kexec.h | 6 +
> include/linux/of.h | 11 +-
> include/linux/tpm.h | 36 +++
> kernel/kexec_file.c | 6 +
> security/integrity/ima/ima_kexec.c | 2 +-
> 13 files changed, 478 insertions(+), 82 deletions(-)
>
>
>base-commit: 3d7cb6b04c3f3115719235cc6866b10326de34cd
>--
>2.35.1
>
>
>_______________________________________________
>kexec mailing list
>kexec@lists.infradead.org
>http://lists.infradead.org/mailman/listinfo/kexec
>

--
Best regards,
Coiby