From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [patch 2/5] KVM: hypercall based pte updates and TLB flushes Date: Sun, 17 Feb 2008 15:13:47 +0200 Message-ID: <47B8330B.6050405@qumranet.com> References: <20080216220924.733723618@redhat.com>> <20080216221220.843135254@redhat.com>> <47B7F017.10902@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net To: Marcelo Tosatti Return-path: In-Reply-To: <47B7F017.10902@qumranet.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Avi Kivity wrote: > Marcelo Tosatti wrote: >> Hypercall based pte updates are faster than faults, and also allow use >> of the lazy MMU mode to batch operations. >> >> Don't report the feature if two dimensional paging is enabled. >> >> Signed-off-by: Marcelo Tosatti >> +/* >> + * We only need to hook operations that are MMU writes. We hook >> these so that >> + * we can use lazy MMU mode to batch these operations. We could >> probably >> + * improve the performance of the host code if we used some of the >> information >> + * here to simplify processing of batched writes. >> + */ >> > > One option is, if the guest promises never to write to a page table > directly, is to avoid write protecting guest page tables. I think the > shadow code can handle it (since the gfn/spte relationship is > maintained by shadow code, and doesn't require reading the guest page > tables), but am not sure. > In addition to reducing mmu work for write protection, this allows more efficient use of large pages. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/