On 09/29/2017 01:07 PM, Roger Pau Monné wrote: > On Fri, Sep 29, 2017 at 05:02:48PM +0000, Boris Ostrovsky wrote: >> On 09/29/2017 11:51 AM, Roger Pau Monné wrote: >>> On Fri, Sep 29, 2017 at 03:33:58PM +0000, Juergen Gross wrote: >>>> On 29/09/17 17:24, Roger Pau Monné wrote: >>>>> On Fri, Sep 29, 2017 at 02:46:53PM +0000, Juergen Gross wrote: >>>>> Then, I also wonder whether it would make sense for this grub to load >>>>> the kernel using the PVH entry point or the native entry point. Would >>>>> it be possible to boot a Linux kernel up to the point where cpuid can >>>>> be used inside of a PVH container? >>>> I don't think today's Linux allows that. This has been discussed >>>> very thoroughly at the time Boris added PVH V2 support to the kernel. >>> OK, I'm not going to insist on that, but my plans for FreeBSD is to >>> make the native entry point capable of booting inside of a PVH >>> container up to the point where cpuid (or whatever method) can be used >>> to detect the environment. >>> >>> Do you recall what's preventing the native entry point from booting >>> inside of a PVH container? If certain emulated devices not present are >>> needed at early boot we could look into either replacing them with >>> other options available inside of a PVH container, or as a last resort >>> making them available on a PVH container. >> Very much IIRC one of the reasons was the fact that zeropage >> (bootparams) needed to be properly formatted. And the hypercall page >> needs to be set up. > But in this case bootparams is going to be setup by grub, so it should > be fine (just like it's done on bare metal).
Yes, I think so. > > Couldn't the hypercall page be setup at some point during early boot? > Not sure if setting it up at the same point HVM does would be fine for > PVH? Probably --- I think the only reason we set it early is because we need to call XENMEM_memory_map to set bootparams. One other thing I noticed is that we need to set acpi_irq_model before hypervisor is discovered (can't remember why) but I suppose this can be worked around. Having said that --- since for direct boot we still need to go via PVH-specific entry point I am not sure how much we will gain by having grub avoid it. -boris _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
