Content-Type: multipart/mixed; boundary="===============6063576187488165893==" MIME-Version: 1.0 From: Michael S. Tsirkin To: kbuild-all@lists.01.org Subject: Re: [PATCH v5 05/14] KVM: X86: Implement ring-based dirty memory tracking Date: Tue, 10 Mar 2020 10:46:56 -0400 Message-ID: <20200310104627-mutt-send-email-mst@kernel.org> In-Reply-To: <20200310141901.GE326977@xz-x1> List-Id: --===============6063576187488165893== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Tue, Mar 10, 2020 at 10:19:01AM -0400, Peter Xu wrote: > On Tue, Mar 10, 2020 at 10:11:30AM -0400, Michael S. Tsirkin wrote: > > On Tue, Mar 10, 2020 at 10:09:21AM -0400, Peter Xu wrote: > > > On Tue, Mar 10, 2020 at 02:31:55AM -0400, Michael S. Tsirkin wrote: > > > > On Mon, Mar 09, 2020 at 05:35:54PM -0400, Peter Xu wrote: > > > > > I'll probably also > > > > > move KVM_DIRTY_LOG_PAGE_OFFSET=3D=3D0 definition to uapi/linux/kv= m.h. > > > > = > > > > = > > > > IMHO KVM_DIRTY_LOG_PAGE_OFFSET is kind of pointless anyway - = > > > > we won't be able to move data around just by changing the > > > > uapi value since userspace isn't > > > > recompiled when kernel changes ... > > > = > > > Yes I think we can even drop this KVM_DIRTY_LOG_PAGE_OFFSET=3D=3D0 > > > definition. IMHO it's only a matter of whether we would like to > > > directly reference this value in the common code (e.g., for kernel > > > virt/kvm_main.c) or we want quite a few of this instead: > > > = > > > #ifdef KVM_DIRTY_LOG_PAGE_OFFSET > > > .. > > > #endif > > = > > Hmm do other arches define it to a different value? > > Maybe I'm confused. > > If they do then it makes sense. > = > Yes they can. So far with this series only x86 will define it to > nonzero (64). But logically other archs can define it to different > values. Oh ok then. somehow I thought it's 0 for all arches. Sorry about the noise, pls ignore this comment. > = > We can reference this to existing offsets that we've defined already > for different archs, like KVM_COALESCED_MMIO_PAGE_OFFSET: > = > - For ppc, it's defined as 1 (arch/powerpc/include/uapi/asm/kvm.h) > - For x86, it's defined as 2 (arch/x86/include/uapi/asm/kvm.h) > - ... > = > Thanks, > > = > > > I slightly prefer to not use lots of "#ifdef"s so I chose to make sure > > > it's defined. However I've no strong opinion on this either. So I'm > > > open to change that if anyone insists with some reasons. > > > = > > > Thanks, > > > = > > > -- = > > > Peter Xu > > = > = > -- = > Peter Xu --===============6063576187488165893==--