From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v9 0/7] KVM: x86: Allow Qemu/KVM to use PVH entry point Date: Thu, 13 Dec 2018 14:15:54 +0100 Message-ID: References: <1544468734-32763-1-git-send-email-maran.wilson@oracle.com> <20181211131825.GD27375@zn.tnic> <5fc083d4-1dbd-f2f9-3059-0e3e8dda9b25@oracle.com> <20181212203901.GI6653@zn.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, bp@suse.de, dave.hansen@linux.intel.com, davem@davemloft.net, gregkh@linuxfoundation.org, hpa@zytor.com, jpoimboe@redhat.com, kirill.shutemov@linux.intel.com, luto@kernel.org, mchehab@kernel.org, mingo@redhat.com, rdunlap@infradead.org, tglx@linutronix.de, thomas.lendacky@amd.com, hch@infradead.org, roger.pau@citrix.com, rkrcmar@redhat.com To: Borislav Petkov , Maran Wilson Return-path: In-Reply-To: <20181212203901.GI6653@zn.tnic> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org 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...