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standalone: should work without explicit CPUID profiles - #1218

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iximeow merged 1 commit into
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ixi/propolis-standalone-cpuid-whoops
Sep 18, 2026
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iximeow merged 1 commit into
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ixi/propolis-standalone-cpuid-whoops

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@iximeow iximeow commented Sep 18, 2026

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93e04e1 added support for selecting specific hypervisor interfaces to propolis-standalone, rather than the prior state of "guest always sees bhyve because of the 0x4000_0000 leaf default in vmm_cpuid.c".

unfortunately, all my test VM configs include a cpuid_profile, so I missed that this change introduced a bug. given a configuration with the default CPUID leaves, the hypervisor interface leaves would get added and misconfigure guests to have all-zero CPUID leaves for every non-hypervisor leaf.

many things go wrong; EDK2 sometimes will do bogus rdmsr and panic propolis on the unimplemented MSR. if you get past EDK2, GRUB checks for the TSC's presence via leaf 1 EDX[4], which is also clear. failing to find a TSC, GRUB gives up trying to boot.

this change has propolis-standalone collect CPUID information more like propolis-server - do not rely on "default" resulting in an empty CPUID profile getting to bhyve, and instead at the point we decide to use a default profile, collect that from bhyve and explicitly provide it later.

93e04e1 added support for selecting specific hypervisor interfaces to
propolis-standalone, rather than the prior state of "guest always sees
bhyve because of the 0x4000_0000 leaf default in vmm_cpuid.c".

unfortunately, all my test VM configs include a `cpuid_profile`, so I
missed that this change introduced a bug. given a configuration with the
default CPUID leaves, the hypervisor interface leaves would get added
and misconfigure guests to have all-zero CPUID leaves for every
non-hypervisor leaf.

many things go wrong; EDK2 sometimes will do bogus rdmsr and panic
propolis on the unimplemented MSR. *if* you get past EDK2, GRUB checks for
the TSC's presence via leaf 1 EDX[4], which is also clear. failing to
find a TSC, GRUB gives up trying to boot.

this change has propolis-standalone collect CPUID information more like
propolis-server - do not rely on "default" resulting in an empty CPUID
profile getting to bhyve, and instead at the point we decide to use a
default profile, collect that from bhyve and explicitly provide it
later.
@iximeow
iximeow requested a review from lgfa29 September 18, 2026 20:25
@iximeow iximeow added the bug Something that isn't working. label Sep 18, 2026
@iximeow

iximeow commented Sep 18, 2026

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Luiz tripped over this as the first person to propolis-standalone without a CPUID profile since I clicked merge on 1194, sorry about the troubles. this isn't an issue for server, because propolis-server does the thing I thought was happening here: get a full CPUID listing and edit in some additional leaves. separately, we should at least smoketest propolis-standalone in CI across a few configs, because breaking test tools is not something I'm very proud of :)

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Tested with the same setup that was failing before and it's working now 🥳

Thanks!

@iximeow
iximeow merged commit 5e201ec into master Sep 18, 2026
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@iximeow
iximeow deleted the ixi/propolis-standalone-cpuid-whoops branch September 18, 2026 21:44
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