bhyve uefi="csm"

Rodney W. Grimes freebsd-rwg at
Mon Oct 22 17:39:04 UTC 2018

> Rodney W. Grimes wrote:
> >> Rodney W. Grimes wrote:
> >> > > Can you tell us a bit about your set up, like are you using helper scripts like libvirt?
> >> > > To answer the question you asked when I run a vm with the CSM firmware it works for me.
> >> >
> >> > You should always be able to boot a vm that uses
> >> > and boots with the non CSM uefi firmware with the
> >> > CSM version of the firmware, failures may start
> >> > to show up if your booting something that is
> >> > either purely legacy, or efi aware but falls
> >> > back to csm because it didnt like something.
> >>
> >> If my goal were to boot FreeDOS in bhyve, would that be ever possible?
> >
> >Today no, due to the fact we do not have a ATA/legacy
> >emulation, but rather only ahci disk emultaion, though
> >I would be wrong on that point if FreeDOS has an ahci
> >disk driver.
> According to 
> FreeDOS has "UDMA drivers for hard disks and DVD drives", is it not the thing? 

No it is not the thing, UDMA was added to legacy ATA at
something like ATA-4,
Ahci does not come into until SATA existed, and iirc
thats around something like ATA-6.

Rod Grimes                                                 rgrimes at

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