Messages in this thread | | | From | NOMURA JUNICHI(野村 淳一) <> | Subject | [Regression v5.19-rc1] crash kexec fails to boot the 2nd kernel (Re: [PATCH v12 38/46] x86/sev: Add SEV-SNP feature detection/setup) | Date | Fri, 24 Jun 2022 00:44:52 +0000 |
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I found crash kexec fails to boot the 2nd kernel since v5.19-rc1 and git bisect points to this as a bad commit:
commit b190a043c49af4587f5e157053f909192820522a Author: Michael Roth <michael.roth@amd.com> Date: Thu Feb 24 10:56:18 2022 -0600
x86/sev: Add SEV-SNP feature detection/setup
Initial/preliminary detection of SEV-SNP is done via the Confidential Computing blob. Check for it prior to the normal SEV/SME feature initialization, and add some sanity checks to confirm it agrees with SEV-SNP CPUID/MSR bits.
The problem seems to occur when find_cc_blob_setup_data() walks setup_data chain. If the code is modified to do nothing in find_cc_blob_setup_data(), the 2nd kernel boots fine.
On my system, the chain of setup_data looks like following on regular boot: setup_data: type=0x3 addr=0x9e9e5018 next=0x9e9dc018 setup_data: type=0x3 addr=0x9e9dc018 next=0x9e9d2018 setup_data: type=0x3 addr=0x9e9d2018 next=0x8a27b018 setup_data: type=0x3 addr=0x8a27b018 next=0x8a218018 setup_data: type=0x3 addr=0x8a218018 next=0x9e9a0018 setup_data: type=0x3 addr=0x9e9a0018 next=0x8a1e6018 setup_data: type=0x3 addr=0x8a1e6018 next=0x8a1b4018 setup_data: type=0x3 addr=0x8a1b4018 next=0x8a182018 setup_data: type=0x3 addr=0x8a182018 next=0x8a056018 setup_data: type=0x3 addr=0x8a056018 next=0x8a020018 setup_data: type=0x3 addr=0x8a020018 next=0x89fea018 setup_data: type=0x3 addr=0x89fea018 next=0x0
OTOH, it looks like following on crash kexec boot: setup_data: type=0x4 addr=0x2e000000 next=0x0
Other places that parses setup_data uses early_memremap() before accessing the data (e.g. parse_setup_data()). I wonder if the lack of remapping causes the problem but find_cc_blob is too early in the boot process for early_memremap to work.
-- Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.
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