From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 7/8] KVM: MMU: VMX cr3 cache support Date: Thu, 06 Mar 2008 16:44:26 +0200 Message-ID: <47D0034A.1040504@qumranet.com> References: <1204475481-16583-8-git-send-email-avi@qumranet.com> <20080306141150.GA19266@dmt> 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: <20080306141150.GA19266@dmt> 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 Marcelo Tosatti wrote: >> >> Here CR3_TARGET_VALUEx is written. >> My question is: >> 1 why is vmcs_writel(CR3_TARGET_VALUE0 + idx*2, cr3); called by >> vmx_set_cr3(), but not called by mmu_free_roots()? >> > > By clearing guest_cr3 entry of the shared area we avoid the guest from > using it. > > So its unecessary to also clear the corresponding CR3_TARGET_VALUE0 > register. > > >> 2 since "cache" is also mapped to guest OS. Is calling >> vmcs_writel(CR3_TARGET_VALUE0 + idx*2, cr3); necessary? >> > > As said above, no, because the guest will check > cache->entry[idx].guest_cr3 before attempting to use a cached host_cr3 > value. > Only if you trust the guest. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- 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/