Re: [PATCH v9 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point

Paolo Bonzini
2018-12-13T13:16:06Z

On 12/12/18 21:39, Borislav Petkov wrote:
> On Tue, Dec 11, 2018 at 11:29:21AM -0800, Maran Wilson wrote:
>> Is your question about what options you need to provide to Qemu? Or is your
>> question about the SW implementation choices?
>>
>> Assuming the former...
> Yeah, that's what I wanted to know. But looking at it, I'm booting
> bzImage here just as quickly and as flexible so I don't see the
> advantage of this new method for my use case here of booting kernels
> in qemu.

It's not firmware that is slow, decompression is. Unlike Xen, which is
using PVH with a regular bzImage and decompression in the host, KVM is
using PVH to boot a vmlinux with no decompression at all.

Paolo

> But maybe there's a good use case where firmware is slow and one doesn't
> really wanna noodle through it or when one does start a gazillion VMs
> per second or whatever...