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Date: Fri, 9 Apr 2021 11:44:14 +0800
From: Shenming Lu <lushenming@...wei.com>
To: Alex Williamson <alex.williamson@...hat.com>,
Cornelia Huck <cohuck@...hat.com>,
Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Joerg Roedel <joro@...tes.org>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
Eric Auger <eric.auger@...hat.com>, <kvm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<iommu@...ts.linux-foundation.org>, <linux-api@...r.kernel.org>
CC: Kevin Tian <kevin.tian@...el.com>,
Lu Baolu <baolu.lu@...ux.intel.com>, <yi.l.liu@...el.com>,
Christoph Hellwig <hch@...radead.org>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Barry Song <song.bao.hua@...ilicon.com>,
<wanghaibin.wang@...wei.com>, <yuzenghui@...wei.com>,
<lushenming@...wei.com>
Subject: [RFC PATCH v3 2/8] vfio/type1: Add a page fault handler
VFIO manages the DMA mapping itself. To support IOPF (on-demand paging)
for VFIO (IOMMU capable) devices, we add a VFIO page fault handler to
serve the reported page faults from the IOMMU driver.
Signed-off-by: Shenming Lu <lushenming@...wei.com>
---
drivers/vfio/vfio_iommu_type1.c | 114 ++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 45cbfd4879a5..ab0ff60ee207 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -101,6 +101,7 @@ struct vfio_dma {
struct task_struct *task;
struct rb_root pfn_list; /* Ex-user pinned pfn list */
unsigned long *bitmap;
+ unsigned long *iopf_mapped_bitmap;
};
struct vfio_batch {
@@ -141,6 +142,16 @@ struct vfio_regions {
size_t len;
};
+/* A global IOPF enabled group list */
+static struct rb_root iopf_group_list = RB_ROOT;
+static DEFINE_MUTEX(iopf_group_list_lock);
+
+struct vfio_iopf_group {
+ struct rb_node node;
+ struct iommu_group *iommu_group;
+ struct vfio_iommu *iommu;
+};
+
#define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \
(!list_empty(&iommu->domain_list))
@@ -157,6 +168,10 @@ struct vfio_regions {
#define DIRTY_BITMAP_PAGES_MAX ((u64)INT_MAX)
#define DIRTY_BITMAP_SIZE_MAX DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
+#define IOPF_MAPPED_BITMAP_GET(dma, i) \
+ ((dma->iopf_mapped_bitmap[(i) / BITS_PER_LONG] \
+ >> ((i) % BITS_PER_LONG)) & 0x1)
+
#define WAITED 1
static int put_pfn(unsigned long pfn, int prot);
@@ -416,6 +431,34 @@ static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
return ret;
}
+/*
+ * Helper functions for iopf_group_list
+ */
+static struct vfio_iopf_group *
+vfio_find_iopf_group(struct iommu_group *iommu_group)
+{
+ struct vfio_iopf_group *iopf_group;
+ struct rb_node *node;
+
+ mutex_lock(&iopf_group_list_lock);
+
+ node = iopf_group_list.rb_node;
+
+ while (node) {
+ iopf_group = rb_entry(node, struct vfio_iopf_group, node);
+
+ if (iommu_group < iopf_group->iommu_group)
+ node = node->rb_left;
+ else if (iommu_group > iopf_group->iommu_group)
+ node = node->rb_right;
+ else
+ break;
+ }
+
+ mutex_unlock(&iopf_group_list_lock);
+ return node ? iopf_group : NULL;
+}
+
static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
{
struct mm_struct *mm;
@@ -3106,6 +3149,77 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
return -EINVAL;
}
+/* VFIO I/O Page Fault handler */
+static int vfio_iommu_type1_dma_map_iopf(struct iommu_fault *fault, void *data)
+{
+ struct device *dev = (struct device *)data;
+ struct iommu_group *iommu_group;
+ struct vfio_iopf_group *iopf_group;
+ struct vfio_iommu *iommu;
+ struct vfio_dma *dma;
+ dma_addr_t iova = ALIGN_DOWN(fault->prm.addr, PAGE_SIZE);
+ int access_flags = 0;
+ unsigned long bit_offset, vaddr, pfn;
+ int ret;
+ enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
+ struct iommu_page_response resp = {0};
+
+ if (fault->type != IOMMU_FAULT_PAGE_REQ)
+ return -EOPNOTSUPP;
+
+ iommu_group = iommu_group_get(dev);
+ if (!iommu_group)
+ return -ENODEV;
+
+ iopf_group = vfio_find_iopf_group(iommu_group);
+ iommu_group_put(iommu_group);
+ if (!iopf_group)
+ return -ENODEV;
+
+ iommu = iopf_group->iommu;
+
+ mutex_lock(&iommu->lock);
+
+ ret = vfio_find_dma_valid(iommu, iova, PAGE_SIZE, &dma);
+ if (ret < 0)
+ goto out_invalid;
+
+ if (fault->prm.perm & IOMMU_FAULT_PERM_READ)
+ access_flags |= IOMMU_READ;
+ if (fault->prm.perm & IOMMU_FAULT_PERM_WRITE)
+ access_flags |= IOMMU_WRITE;
+ if ((dma->prot & access_flags) != access_flags)
+ goto out_invalid;
+
+ bit_offset = (iova - dma->iova) >> PAGE_SHIFT;
+ if (IOPF_MAPPED_BITMAP_GET(dma, bit_offset))
+ goto out_success;
+
+ vaddr = iova - dma->iova + dma->vaddr;
+
+ if (vfio_pin_page_external(dma, vaddr, &pfn, true))
+ goto out_invalid;
+
+ if (vfio_iommu_map(iommu, iova, pfn, 1, dma->prot)) {
+ if (put_pfn(pfn, dma->prot))
+ vfio_lock_acct(dma, -1, true);
+ goto out_invalid;
+ }
+
+ bitmap_set(dma->iopf_mapped_bitmap, bit_offset, 1);
+
+out_success:
+ status = IOMMU_PAGE_RESP_SUCCESS;
+
+out_invalid:
+ mutex_unlock(&iommu->lock);
+ resp.version = IOMMU_PAGE_RESP_VERSION_1;
+ resp.grpid = fault->prm.grpid;
+ resp.code = status;
+ iommu_page_response(dev, &resp);
+ return 0;
+}
+
static long vfio_iommu_type1_ioctl(void *iommu_data,
unsigned int cmd, unsigned long arg)
{
--
2.19.1
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