From patchwork Wed Dec 18 16:01:27 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 3370621 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 6A6DBC0D4A for ; Wed, 18 Dec 2013 16:01:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B1407201BE for ; Wed, 18 Dec 2013 16:01:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CACC201B9 for ; Wed, 18 Dec 2013 16:01:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755014Ab3LRQBo (ORCPT ); Wed, 18 Dec 2013 11:01:44 -0500 Received: from cantor2.suse.de ([195.135.220.15]:58028 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754931Ab3LRQBl (ORCPT ); Wed, 18 Dec 2013 11:01:41 -0500 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B8C69AC33; Wed, 18 Dec 2013 16:01:40 +0000 (UTC) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: "kvm@vger.kernel.org mailing list" , Paolo Bonzini , Gleb Natapov , Paul Mackerras Subject: [PULL 01/12] KVM: PPC: Book3S HV: Fix physical address calculations Date: Wed, 18 Dec 2013 17:01:27 +0100 Message-Id: <1387382498-19817-2-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1387382498-19817-1-git-send-email-agraf@suse.de> References: <1387382498-19817-1-git-send-email-agraf@suse.de> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable 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: Paul Mackerras This fixes a bug in kvmppc_do_h_enter() where the physical address for a page can be calculated incorrectly if transparent huge pages (THP) are active. Until THP came along, it was true that if we encountered a large (16M) page in kvmppc_do_h_enter(), then the associated memslot must be 16M aligned for both its guest physical address and the userspace address, and the physical address calculations in kvmppc_do_h_enter() assumed that. With THP, that is no longer true. In the case where we are using MMU notifiers and the page size that we get from the Linux page tables is larger than the page being mapped by the guest, we need to fill in some low-order bits of the physical address. Without THP, these bits would be the same in the guest physical address (gpa) and the host virtual address (hva). With THP, they can be different, and we need to use the bits from hva rather than gpa. In the case where we are not using MMU notifiers, the host physical address we get from the memslot->arch.slot_phys[] array already includes the low-order bits down to the PAGE_SIZE level, even if we are using large pages. Thus we can simplify the calculation in this case to just add in the remaining bits in the case where PAGE_SIZE is 64k and the guest is mapping a 4k page. The same bug exists in kvmppc_book3s_hv_page_fault(). The basic fix is to use psize (the page size from the HPTE) rather than pte_size (the page size from the Linux PTE) when updating the HPTE low word in r. That means that pfn needs to be computed to PAGE_SIZE granularity even if the Linux PTE is a huge page PTE. That can be arranged simply by doing the page_to_pfn() before setting page to the head of the compound page. If psize is less than PAGE_SIZE, then we need to make sure we only update the bits from PAGE_SIZE upwards, in order not to lose any sub-page offset bits in r. On the other hand, if psize is greater than PAGE_SIZE, we need to make sure we don't bring in non-zero low order bits in pfn, hence we mask (pfn << PAGE_SHIFT) with ~(psize - 1). Signed-off-by: Paul Mackerras Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_64_mmu_hv.c | 12 +++++++++--- arch/powerpc/kvm/book3s_hv_rm_mmu.c | 4 ++-- 2 files changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index f3ff587..47bbeaf 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -665,6 +665,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, return -EFAULT; } else { page = pages[0]; + pfn = page_to_pfn(page); if (PageHuge(page)) { page = compound_head(page); pte_size <<= compound_order(page); @@ -689,7 +690,6 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, } rcu_read_unlock_sched(); } - pfn = page_to_pfn(page); } ret = -EFAULT; @@ -707,8 +707,14 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, r = (r & ~(HPTE_R_W|HPTE_R_I|HPTE_R_G)) | HPTE_R_M; } - /* Set the HPTE to point to pfn */ - r = (r & ~(HPTE_R_PP0 - pte_size)) | (pfn << PAGE_SHIFT); + /* + * Set the HPTE to point to pfn. + * Since the pfn is at PAGE_SIZE granularity, make sure we + * don't mask out lower-order bits if psize < PAGE_SIZE. + */ + if (psize < PAGE_SIZE) + psize = PAGE_SIZE; + r = (r & ~(HPTE_R_PP0 - psize)) | ((pfn << PAGE_SHIFT) & ~(psize - 1)); if (hpte_is_writable(r) && !write_ok) r = hpte_make_readonly(r); ret = RESUME_GUEST; diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c index 9c51544..fddbf98 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c @@ -225,6 +225,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags, is_io = pa & (HPTE_R_I | HPTE_R_W); pte_size = PAGE_SIZE << (pa & KVMPPC_PAGE_ORDER_MASK); pa &= PAGE_MASK; + pa |= gpa & ~PAGE_MASK; } else { /* Translate to host virtual address */ hva = __gfn_to_hva_memslot(memslot, gfn); @@ -238,13 +239,12 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags, ptel = hpte_make_readonly(ptel); is_io = hpte_cache_bits(pte_val(pte)); pa = pte_pfn(pte) << PAGE_SHIFT; + pa |= hva & (pte_size - 1); } } if (pte_size < psize) return H_PARAMETER; - if (pa && pte_size > psize) - pa |= gpa & (pte_size - 1); ptel &= ~(HPTE_R_PP0 - psize); ptel |= pa;