From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v6 0/6] kvm, mem-hotplug: Do not pin ept identity pagetable and apic access page. Date: Tue, 16 Sep 2014 13:44:42 +0200 Message-ID: <541822AA.6060200@redhat.com> References: <1410864122-12434-1-git-send-email-tangchen@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, laijs@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, guz.fnst@cn.fujitsu.com, linux-kernel@vger.kernel.org To: Tang Chen , gleb@kernel.org, mtosatti@redhat.com, nadav.amit@gmail.com, jan.kiszka@web.de Return-path: In-Reply-To: <1410864122-12434-1-git-send-email-tangchen@cn.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Il 16/09/2014 12:41, Tang Chen ha scritto: > ept identity pagetable and apic access page in kvm are pinned in memory. > As a result, they cannot be migrated/hot-removed. > > But actually they don't need to be pinned in memory. > > [For ept identity page] > Just do not pin it. When it is migrated, guest will be able to find the > new page in the next ept violation. > > [For apic access page] > The hpa of apic access page is stored in VMCS APIC_ACCESS_ADDR pointer. > When apic access page is migrated, we update VMCS APIC_ACCESS_ADDR pointer > for each vcpu in addition. > > NOTE: Tested with -cpu xxx,-x2apic option. > But since nested vm pins some other pages in memory, if user uses nested > vm, memory hot-remove will not work. > > Change log v5 -> v6: > 1. Patch 1/6 has been applied by Paolo Bonzini , just resend it. > 2. Simplify comment in alloc_identity_pagetable() and add a BUG_ON() in patch 2/6. > 3. Move err initialization forward in patch 3/6. > 4. Rename vcpu_reload_apic_access_page() to kvm_vcpu_reload_apic_access_page() and > use it instead of kvm_reload_apic_access_page() in nested_vmx_vmexit() in patch 5/6. > 5. Reuse kvm_vcpu_reload_apic_access_page() in prepare_vmcs02() and vmx_vcpu_reset() in patch 6/6. > 6. Remove original patch 7 since we are not able to handle the situation in nested vm. I'll push 1-3 soon to kvm/queue. I think v7 will be good. :) Paolo