Messages in this thread Patch in this message | | | Date | Wed, 17 Aug 2022 10:40:40 +0200 | From | Jeremi Piotrowski <> | Subject | Re: [Regression v5.19-rc1] kernel fails to boot, no console output (Re: [PATCH v12 38/46] x86/sev: Add SEV-SNP feature detection/setup) |
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On Tue, Aug 16, 2022 at 10:06:37AM -0500, Michael Roth wrote: > On Tue, Aug 16, 2022 at 04:25:30PM +0200, Jeremi Piotrowski wrote: > > On Fri, Jun 24, 2022 at 12:44:52AM +0000, NOMURA JUNICHI(野村 淳一) wrote: > > > 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. > > > > > > > Hi Michael, > > > > I too have bisected an issue to this commit and my issue is not fixed by > > b57feed2cc2622ae14b2fa62f19e973e5e0a60cf. I have a Dell R6515 with AMD EPYC > > 7513 that is supposed to act as an SNP host, but after v5.19-rc1 I don't get > > any console output and the machine resets shortly after grub loads the > > kernel. > > > > The bisect was done on 5.18+SNP patches that were merged into 5.19-rc1, this > > is the full patch list: > > > > git log --oneline v5.18-rc1..eb39e37d5cebdf0f63ee2a315fc23b035d81b4b0^2 > > > > If I comment out the following lines, the machine boots correctly and if I also > > have the SNP host patches applied SNP guests work correctly. Applying > > Hi Jeremi, > > Can you retry with earlyprintk enabled via kernel cmdline? I'm trying to see > if you're getting these messages and making it past the boot/compressed kernel > (which has its own snp_init()): > > EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path^M > early console in extract_kernel^M > input_data: 0x00000000352fd4cc^M > input_len: 0x0000000000c5adcb^M > output: 0x0000000033000000^M > output_len: 0x0000000002f07ec4^M > kernel_total_size: 0x000000000242c000^M > needed_size: 0x0000000003000000^M > trampoline_32bit: 0x000000000009d000^M > Physical KASLR using RDRAND RDTSC...^M > Virtual KASLR using RDRAND RDTSC...^M > ^M > Decompressing Linux... Parsing ELF... Performing relocations... done.^M > Booting the kernel. > [ 0.000000] Linux version ... >
Ok, I was missing CONFIG_X86_VERBOSE_BOOTUP=y. With that added, when the kernel doesn't boot this is the output:
Loading Linux 5.18.0-snp-host-dev+ ... Loading initial ramdisk ... early console in extract_kernel input_data: 0x00000000068824cc input_len: 0x000000000092cb45 output: 0x0000000004200000 output_len: 0x0000000002f5eff4 kernel_total_size: 0x0000000002430000 needed_size: 0x0000000003000000 trampoline_32bit: 0x000000000009d000 Physical KASLR using RDRAND RDTSC... Virtual KASLR using RDRAND RDTSC... Decompressing Linux... Parsing ELF... Performing relocations... done. Booting the kernel.
> Also, instead of commenting out snp_init() below, can you retry with this > change instead? > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 7b668f91c9ab..e9e55a99d60f 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -2083,9 +2083,12 @@ static __init struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) > * boot/decompression kernel, the CC blob may have been passed via > * setup_data instead. > */ > +#if 0 > cc_info = find_cc_blob_setup_data(bp); > if (!cc_info) > return NULL; > +#endif > + return NULL; > > found_cc_info: > if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) >
This version does not boot.
> And if that does not avoid the issue, can you retry with the below change > (without the above change in place)? > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 7b668f91c9ab..0b430f98e053 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -2073,10 +2073,12 @@ static __init struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) > struct cc_blob_sev_info *cc_info; > > /* Boot kernel would have passed the CC blob via boot_params. */ > +#if 0 > if (bp->cc_blob_address) { > cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address; > goto found_cc_info; > } > +#endif > > /* > * If kernel was booted directly, without the use of the > @@ -2087,7 +2089,7 @@ static __init struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) > if (!cc_info) > return NULL; > > -found_cc_info: > +//found_cc_info: > if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) > snp_abort(); > > Trying to see if you're hitting a separate issue or not.
This version boots correctly.
> > Thanks, > > Mike > >
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