From patchwork Mon May 26 09:48:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Mackerras X-Patchwork-Id: 4240941 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id DE5D69F1E7 for ; Mon, 26 May 2014 09:49:16 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id ECF2A201B4 for ; Mon, 26 May 2014 09:49:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B94292017D for ; Mon, 26 May 2014 09:49:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751936AbaEZJtJ (ORCPT ); Mon, 26 May 2014 05:49:09 -0400 Received: from ozlabs.org ([103.22.144.67]:51919 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbaEZJs5 (ORCPT ); Mon, 26 May 2014 05:48:57 -0400 Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id EA53B1400DD; Mon, 26 May 2014 19:48:53 +1000 (EST) From: Paul Mackerras To: Alexander Graf Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH 5/8] KVM: PPC: Book3S HV: Fix dirty map for hugepages Date: Mon, 26 May 2014 19:48:38 +1000 Message-Id: <1401097721-5030-6-git-send-email-paulus@samba.org> X-Mailer: git-send-email 2.0.0.rc2 In-Reply-To: <1401097721-5030-1-git-send-email-paulus@samba.org> References: <1401097721-5030-1-git-send-email-paulus@samba.org> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Alexey Kardashevskiy The dirty map that we construct for the KVM_GET_DIRTY_LOG ioctl has one bit per system page (4K/64K). Currently, we only set one bit in the map for each HPT entry with the Change bit set, even if the HPT is for a large page (e.g., 16MB). Userspace then considers only the first system page dirty, though in fact the guest may have modified anywhere in the large page. To fix this, we make kvm_test_clear_dirty() return the actual number of pages that are dirty (and rename it to kvm_test_clear_dirty_npages() to emphasize that that's what it returns). In kvmppc_hv_get_dirty_log() we then set that many bits in the dirty map. Signed-off-by: Alexey Kardashevskiy Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 4e22ecb..96c9044 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -1060,22 +1060,27 @@ void kvm_set_spte_hva_hv(struct kvm *kvm, unsigned long hva, pte_t pte) kvm_handle_hva(kvm, hva, kvm_unmap_rmapp); } -static int kvm_test_clear_dirty(struct kvm *kvm, unsigned long *rmapp) +/* + * Returns the number of system pages that are dirty. + * This can be more than 1 if we find a huge-page HPTE. + */ +static int kvm_test_clear_dirty_npages(struct kvm *kvm, unsigned long *rmapp) { struct revmap_entry *rev = kvm->arch.revmap; unsigned long head, i, j; + unsigned long n; unsigned long *hptep; - int ret = 0; + int npages_dirty = 0; retry: lock_rmap(rmapp); if (*rmapp & KVMPPC_RMAP_CHANGED) { *rmapp &= ~KVMPPC_RMAP_CHANGED; - ret = 1; + npages_dirty = 1; } if (!(*rmapp & KVMPPC_RMAP_PRESENT)) { unlock_rmap(rmapp); - return ret; + return npages_dirty; } i = head = *rmapp & KVMPPC_RMAP_INDEX; @@ -1106,13 +1111,16 @@ static int kvm_test_clear_dirty(struct kvm *kvm, unsigned long *rmapp) rev[i].guest_rpte |= HPTE_R_C; note_hpte_modification(kvm, &rev[i]); } - ret = 1; + n = hpte_page_size(hptep[0], hptep[1]); + n = (n + PAGE_SIZE - 1) >> PAGE_SHIFT; + if (n > npages_dirty) + npages_dirty = n; } hptep[0] &= ~HPTE_V_HVLOCK; } while ((i = j) != head); unlock_rmap(rmapp); - return ret; + return npages_dirty; } static void harvest_vpa_dirty(struct kvmppc_vpa *vpa, @@ -1136,15 +1144,22 @@ static void harvest_vpa_dirty(struct kvmppc_vpa *vpa, long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long *map) { - unsigned long i; + unsigned long i, j; unsigned long *rmapp; struct kvm_vcpu *vcpu; preempt_disable(); rmapp = memslot->arch.rmap; for (i = 0; i < memslot->npages; ++i) { - if (kvm_test_clear_dirty(kvm, rmapp) && map) - __set_bit_le(i, map); + int npages = kvm_test_clear_dirty_npages(kvm, rmapp); + /* + * Note that if npages > 0 then i must be a multiple of npages, + * since we always put huge-page HPTEs in the rmap chain + * corresponding to their page base address. + */ + if (npages && map) + for (j = i; npages; ++j, --npages) + __set_bit_le(j, map); ++rmapp; }