Date: Wed, 21 Feb 2018 08:59:47 -0800 From: Peter Grehan <grehan@freebsd.org> To: Fabian Freyer <fabian.freyer@physik.tu-berlin.de> Cc: freebsd-virtualization@freebsd.org Subject: Re: VMX exit reason=33 and general userboot.so questions Message-ID: <0142d062-ca13-6917-bb06-28cac727680b@freebsd.org> In-Reply-To: <BA57D57B-08B0-45DB-B200-C5C31994AAC7@physik.tu-berlin.de> References: <BA57D57B-08B0-45DB-B200-C5C31994AAC7@physik.tu-berlin.de>
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Hi Fabian,
> exit_reason 33
From the Intel SDM, vol 3B Appendix C, this error is "VM-entry failure
due to invalid guest state".
These errors can be difficult to debug given the large amount of guest
state involved :(
However, looking at the state from your dump:
> tr desc[0] 0x0000000000000000/0x00000000/0x00000000
I believe you will have to set this. Here's the comment and relevant
code fragment from grub2-bhyve
grub-core/kern/emu/bhyve_hostif.c:grub_emu_bhyve_boot32()
/*
* XXX TR is pointing to null selector even though we set the
* TSS segment to be usable with a base address and limit of 0.
* Has to be 8b or vmenter will fail
*/
desc_access = 0x0000008b;
assert(vm_set_desc(bhyve_ctx, 0, VM_REG_GUEST_TR, 0x1000, 0x67,
desc_access) == 0);
grub2-bhyve has been able to load/boot multiboot images, so I suspect
the register settings in grub_emu_bhyve_boot32() are a good place to
start from.
later,
Peter.
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