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SubjectRe: [PATCH v9 2/7] vfio/type1: vfio_find_dma accepting a type argument
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Hi Alex,
On 05/10/2016 12:49 AM, Alex Williamson wrote:
> On Wed, 4 May 2016 11:54:13 +0000
> Eric Auger <eric.auger@linaro.org> 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 <eric.auger@linaro.org>
>> ---
>> 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;
>> }
>

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