From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753454AbbC0O5E (ORCPT ); Fri, 27 Mar 2015 10:57:04 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:50622 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752987AbbC0O46 (ORCPT ); Fri, 27 Mar 2015 10:56:58 -0400 From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Cc: Alexey Kardashevskiy , Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , linux-kernel@vger.kernel.org Subject: [PATCH kernel v7 07/31] vfio: powerpc/spapr: Moving pinning/unpinning to helpers Date: Sat, 28 Mar 2015 01:54:51 +1100 Message-Id: <1427468115-2224-8-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1427468115-2224-1-git-send-email-aik@ozlabs.ru> References: <1427468115-2224-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15032714-0017-0000-0000-000000FE0088 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a pretty mechanical patch to make next patches simpler. New tce_iommu_unuse_page() helper does put_page() now but it might skip that after the memory registering patch applied. As we are here, this removes unnecessary checks for a value returned by pfn_to_page() as it cannot possibly return NULL. This moves tce_iommu_disable() later to let tce_iommu_clear() know if the container has been enabled because if it has not been, then put_page() must not be called on TCEs from the TCE table. This situation is not yet possible but it will after KVM acceleration patchset is applied. Signed-off-by: Alexey Kardashevskiy --- Changes: v6: * tce_get_hva() returns hva via a pointer --- drivers/vfio/vfio_iommu_spapr_tce.c | 68 +++++++++++++++++++++++++++---------- 1 file changed, 50 insertions(+), 18 deletions(-) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index c137bb3..ec5ee83 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -196,7 +196,6 @@ static void tce_iommu_release(void *iommu_data) struct iommu_table *tbl = container->tbl; WARN_ON(tbl && !tbl->it_group); - tce_iommu_disable(container); if (tbl) { tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); @@ -204,63 +203,96 @@ static void tce_iommu_release(void *iommu_data) if (tbl->it_group) tce_iommu_detach_group(iommu_data, tbl->it_group); } + + tce_iommu_disable(container); + mutex_destroy(&container->lock); kfree(container); } +static void tce_iommu_unuse_page(struct tce_container *container, + unsigned long oldtce) +{ + struct page *page; + + if (!(oldtce & (TCE_PCI_READ | TCE_PCI_WRITE))) + return; + + /* + * VFIO cannot map/unmap when a container is not enabled so + * we would not need this check but KVM could map/unmap and if + * this happened, we must not put pages as KVM does not get them as + * it expects memory pre-registation to do this part. + */ + if (!container->enabled) + return; + + page = pfn_to_page(__pa(oldtce) >> PAGE_SHIFT); + + if (oldtce & TCE_PCI_WRITE) + SetPageDirty(page); + + put_page(page); +} + static int tce_iommu_clear(struct tce_container *container, struct iommu_table *tbl, unsigned long entry, unsigned long pages) { unsigned long oldtce; - struct page *page; for ( ; pages; --pages, ++entry) { oldtce = iommu_clear_tce(tbl, entry); if (!oldtce) continue; - page = pfn_to_page(oldtce >> PAGE_SHIFT); - WARN_ON(!page); - if (page) { - if (oldtce & TCE_PCI_WRITE) - SetPageDirty(page); - put_page(page); - } + tce_iommu_unuse_page(container, (unsigned long) __va(oldtce)); } return 0; } +static int tce_get_hva(unsigned long tce, unsigned long *hva) +{ + struct page *page = NULL; + enum dma_data_direction direction = iommu_tce_direction(tce); + + if (get_user_pages_fast(tce & PAGE_MASK, 1, + direction != DMA_TO_DEVICE, &page) != 1) + return -EFAULT; + + *hva = (unsigned long) page_address(page); + + return 0; +} + static long tce_iommu_build(struct tce_container *container, struct iommu_table *tbl, unsigned long entry, unsigned long tce, unsigned long pages) { long i, ret = 0; - struct page *page = NULL; + struct page *page; unsigned long hva; enum dma_data_direction direction = iommu_tce_direction(tce); for (i = 0; i < pages; ++i) { - ret = get_user_pages_fast(tce & PAGE_MASK, 1, - direction != DMA_TO_DEVICE, &page); - if (unlikely(ret != 1)) { - ret = -EFAULT; + ret = tce_get_hva(tce, &hva); + if (ret) break; - } + page = pfn_to_page(__pa(hva) >> PAGE_SHIFT); if (!tce_page_is_contained(page, tbl->it_page_shift)) { ret = -EPERM; break; } - hva = (unsigned long) page_address(page) + - (tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK); + /* Preserve offset within IOMMU page */ + hva |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK; ret = iommu_tce_build(tbl, entry + i, hva, direction); if (ret) { - put_page(page); + tce_iommu_unuse_page(container, hva); pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n", __func__, entry << tbl->it_page_shift, tce, ret); -- 2.0.0