Messages in this thread | | | Date | Mon, 6 Feb 2023 11:58:47 -0600 | From | Kim Phillips <> | Subject | Re: [PATCH v6 07/11] x86/smpboot: Disable parallel boot for AMD CPUs |
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On 2/4/23 9:40 AM, David Woodhouse wrote: > On Fri, 2023-02-03 at 13:48 -0600, Kim Phillips wrote: >> If I: >> >> - take dwmw2's parallel-6.2-rc6 branch (commit 459d1c46dbd1) >> - remove the set_cpu_bug(c, X86_BUG_NO_PARALLEL_BRINGUP) line from amd.c >> >> Then: >> >> - a Ryzen 3000 (Picasso A1/Zen+) notebook I have access to fails to boot. >> - Zen 2,3,4-based servers boot fine >> - a Zen1-based server doesn't boot. > > I've changed it to use CPUID 0xb only if we're actually in x2apic mode, > which Boris tells me won't be the case on Zen1 because that doesn't > support X2APIC. > > When we're not in x2apic mode, we can use CPUID 0x1 because the 8 bits > of APIC ID we find there are perfectly sufficient. > > New tree in the same place as before, commit ce7e2d1e046a for the > parallel-6.2-rc6-part1 tag and 17bbd12ee03 for parallel-6.2-rc6.
Thanks, Zen 1 through 4 based servers all boot both those two tree commits successfully.
I'll try that Ryzen again later.
Kim
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