From patchwork Wed Jun 20 08:42:58 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Kardashevskiy X-Patchwork-Id: 932036 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=kvm-ppc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ozlabs.ru Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 419ddR2gZ7z9s7F for ; Wed, 20 Jun 2018 18:43:07 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754586AbeFTInE (ORCPT ); Wed, 20 Jun 2018 04:43:04 -0400 Received: from 107-173-13-209-host.colocrossing.com ([107.173.13.209]:58255 "EHLO ozlabs.ru" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753918AbeFTInD (ORCPT ); Wed, 20 Jun 2018 04:43:03 -0400 Received: from vpl1.ozlabs.ibm.com (localhost [IPv6:::1]) by ozlabs.ru (Postfix) with ESMTP id E8C4FAE80001; Wed, 20 Jun 2018 04:41:51 -0400 (EDT) From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , David Gibson , kvm-ppc@vger.kernel.org, Paul Mackerras Subject: [PATCH kernel] KVM: PPC: Fix hardware and emulated TCE tables matching Date: Wed, 20 Jun 2018 18:42:58 +1000 Message-Id: <20180620084258.1155-1-aik@ozlabs.ru> X-Mailer: git-send-email 2.11.0 Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org When attaching a hardware table to LIOBN in KVM, we match table parameters such as page size, table offset and table size. However the tables are created via very different paths - VFIO and KVM - and the VFIO path goes through the platform code which has minimum TCE page size requirement (which is 4K but since we allocate memory by pages and cannot avoid alignment anyway, we align to 64k pages for powernv_defconfig). So when we match the tables, one might be bigger that the other which means the hardware table cannot get attached to LIOBN and DMA mapping fails. This removes the table size alignment from the guest visible table. This does not affect the memory allocation which is still aligned - kvmppc_tce_pages() takes care of this. This relaxes the check we do when attaching tables to allow the hardware table be bigger than the guest visible table. Ideally we want the KVM table to cover the same space as the hardware table does but since the hardware table may use multiple levels, and all levels must use the same table size (IODA2 design), the area it can actually cover might get very different from the window size which the guest requested, even though the guest won't map it all. Fixes: ca1fc489cf "KVM: PPC: Book3S: Allow backing bigger guest IOMMU pages with smaller physical pages" Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson --- arch/powerpc/kvm/book3s_64_vio.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 8c456fa..8167ce8 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -180,7 +180,7 @@ extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd, if ((tbltmp->it_page_shift <= stt->page_shift) && (tbltmp->it_offset << tbltmp->it_page_shift == stt->offset << stt->page_shift) && - (tbltmp->it_size << tbltmp->it_page_shift == + (tbltmp->it_size << tbltmp->it_page_shift >= stt->size << stt->page_shift)) { /* * Reference the table to avoid races with @@ -296,7 +296,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, { struct kvmppc_spapr_tce_table *stt = NULL; struct kvmppc_spapr_tce_table *siter; - unsigned long npages, size; + unsigned long npages, size = args->size; int ret = -ENOMEM; int i; @@ -304,7 +304,6 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, (args->offset + args->size > (ULLONG_MAX >> args->page_shift))) return -EINVAL; - size = _ALIGN_UP(args->size, PAGE_SIZE >> 3); npages = kvmppc_tce_pages(size); ret = kvmppc_account_memlimit(kvmppc_stt_pages(npages), true); if (ret)