From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752990AbcEJOzc (ORCPT ); Tue, 10 May 2016 10:55:32 -0400 Received: from mail-wm0-f53.google.com ([74.125.82.53]:35962 "EHLO mail-wm0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752476AbcEJOza (ORCPT ); Tue, 10 May 2016 10:55:30 -0400 Subject: Re: [PATCH v9 2/7] vfio/type1: vfio_find_dma accepting a type argument To: Alex Williamson References: <1462362858-2925-1-git-send-email-eric.auger@linaro.org> <1462362858-2925-3-git-send-email-eric.auger@linaro.org> <20160509164928.518a05a8@t450s.home> Cc: eric.auger@st.com, robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net, marc.zyngier@arm.com, christoffer.dall@linaro.org, linux-arm-kernel@lists.infradead.org, patches@linaro.org, linux-kernel@vger.kernel.org, Bharat.Bhushan@freescale.com, pranav.sawargaonkar@gmail.com, p.fedin@samsung.com, iommu@lists.linux-foundation.org, Jean-Philippe.Brucker@arm.com, julien.grall@arm.com, yehuday@marvell.com From: Eric Auger Message-ID: <5731F60B.6040105@linaro.org> Date: Tue, 10 May 2016 16:54:03 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160509164928.518a05a8@t450s.home> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alex, On 05/10/2016 12:49 AM, Alex Williamson wrote: > On Wed, 4 May 2016 11:54:13 +0000 > Eric Auger wrote: > >> In our RB-tree we now have slots of different types (USER and RESERVED). >> It becomes useful to be able to search for dma slots of a specific type or >> any type. This patch proposes an implementation for that modality and also >> changes the existing callers using the USER type. >> >> Signed-off-by: Eric Auger >> --- >> drivers/vfio/vfio_iommu_type1.c | 63 ++++++++++++++++++++++++++++++++++------- >> 1 file changed, 53 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index aaf5a6c..2d769d4 100644 >> --- a/drivers/vfio/vfio_iommu_type1.c >> +++ b/drivers/vfio/vfio_iommu_type1.c >> @@ -98,23 +98,64 @@ struct vfio_group { >> * into DMA'ble space using the IOMMU >> */ >> >> -static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu, >> - dma_addr_t start, size_t size) >> +/** >> + * vfio_find_dma_from_node: looks for a dma slot intersecting a window >> + * from a given rb tree node >> + * @top: top rb tree node where the search starts (including this node) >> + * @start: window start >> + * @size: window size >> + * @type: window type >> + */ >> +static struct vfio_dma *vfio_find_dma_from_node(struct rb_node *top, >> + dma_addr_t start, size_t size, >> + enum vfio_iova_type type) >> { >> - struct rb_node *node = iommu->dma_list.rb_node; >> + struct rb_node *node = top; >> + struct vfio_dma *dma; >> >> while (node) { >> - struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node); >> - >> + dma = rb_entry(node, struct vfio_dma, node); >> if (start + size <= dma->iova) >> node = node->rb_left; >> else if (start >= dma->iova + dma->size) >> node = node->rb_right; >> else >> + break; >> + } >> + if (!node) >> + return NULL; >> + >> + /* a dma slot intersects our window, check the type also matches */ >> + if (type == VFIO_IOVA_ANY || dma->type == type) >> + return dma; >> + >> + /* restart 2 searches skipping the current node */ >> + if (start < dma->iova) { >> + dma = vfio_find_dma_from_node(node->rb_left, start, >> + size, type); >> + if (dma) >> return dma; >> } >> + if (start + size > dma->iova + dma->size) >> + dma = vfio_find_dma_from_node(node->rb_right, start, >> + size, type); > > It might be nice to split this little bit of trickery out to a separate > patch so that you can better explain what it does. It's really not > needed until we start creating user-type entries, so it shouldn't hurt > bisection. OK I will Regards Eric > >> + return dma; >> +} >> + >> +/** >> + * vfio_find_dma: find a dma slot intersecting a given window >> + * @iommu: vfio iommu handle >> + * @start: window base iova >> + * @size: window size >> + * @type: window type >> + */ >> +static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu, >> + dma_addr_t start, size_t size, >> + enum vfio_iova_type type) >> +{ >> + struct rb_node *top_node = iommu->dma_list.rb_node; >> >> - return NULL; >> + return vfio_find_dma_from_node(top_node, start, size, type); >> } >> >> static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new) >> @@ -488,19 +529,21 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu, >> * mappings within the range. >> */ >> if (iommu->v2) { >> - dma = vfio_find_dma(iommu, unmap->iova, 0); >> + dma = vfio_find_dma(iommu, unmap->iova, 0, VFIO_IOVA_USER); >> if (dma && dma->iova != unmap->iova) { >> ret = -EINVAL; >> goto unlock; >> } >> - dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0); >> + dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0, >> + VFIO_IOVA_USER); >> if (dma && dma->iova + dma->size != unmap->iova + unmap->size) { >> ret = -EINVAL; >> goto unlock; >> } >> } >> >> - while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) { >> + while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size, >> + VFIO_IOVA_USER))) { >> if (!iommu->v2 && unmap->iova > dma->iova) >> break; >> unmapped += dma->size; >> @@ -604,7 +647,7 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu, >> >> mutex_lock(&iommu->lock); >> >> - if (vfio_find_dma(iommu, iova, size)) { >> + if (vfio_find_dma(iommu, iova, size, VFIO_IOVA_ANY)) { >> mutex_unlock(&iommu->lock); >> return -EEXIST; >> } >