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From: Shenming Lu <lushenming@huawei.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Eric Auger <eric.auger@redhat.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<iommu@lists.linux-foundation.org>, <linux-api@vger.kernel.org>
Cc: Kevin Tian <kevin.tian@intel.com>,
	Lu Baolu <baolu.lu@linux.intel.com>, <yi.l.liu@intel.com>,
	Christoph Hellwig <hch@infradead.org>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Barry Song <song.bao.hua@hisilicon.com>,
	<wanghaibin.wang@huawei.com>, <yuzenghui@huawei.com>,
	<lushenming@huawei.com>
Subject: [RFC PATCH v3 3/8] vfio/type1: Add an MMU notifier to avoid pinning
Date: Fri, 9 Apr 2021 11:44:15 +0800	[thread overview]
Message-ID: <20210409034420.1799-4-lushenming@huawei.com> (raw)
In-Reply-To: <20210409034420.1799-1-lushenming@huawei.com>

To avoid pinning pages when they are mapped in IOMMU page tables, we
add an MMU notifier to tell the addresses which are no longer valid
and try to unmap them.

Signed-off-by: Shenming Lu <lushenming@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 112 +++++++++++++++++++++++++++++++-
 1 file changed, 109 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index ab0ff60ee207..1cb9d1f2717b 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -40,6 +40,7 @@
 #include <linux/notifier.h>
 #include <linux/dma-iommu.h>
 #include <linux/irqdomain.h>
+#include <linux/mmu_notifier.h>
 
 #define DRIVER_VERSION  "0.2"
 #define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
@@ -69,6 +70,7 @@ struct vfio_iommu {
 	struct mutex		lock;
 	struct rb_root		dma_list;
 	struct blocking_notifier_head notifier;
+	struct mmu_notifier	mn;
 	unsigned int		dma_avail;
 	unsigned int		vaddr_invalid_count;
 	uint64_t		pgsize_bitmap;
@@ -1204,6 +1206,72 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
 	return unlocked;
 }
 
+/* Unmap the IOPF mapped pages in the specified range. */
+static void vfio_unmap_partial_iopf(struct vfio_iommu *iommu,
+				    struct vfio_dma *dma,
+				    dma_addr_t start, dma_addr_t end)
+{
+	struct iommu_iotlb_gather *gathers;
+	struct vfio_domain *d;
+	int i, num_domains = 0;
+
+	list_for_each_entry(d, &iommu->domain_list, next)
+		num_domains++;
+
+	gathers = kzalloc(sizeof(*gathers) * num_domains, GFP_KERNEL);
+	if (gathers) {
+		for (i = 0; i < num_domains; i++)
+			iommu_iotlb_gather_init(&gathers[i]);
+	}
+
+	while (start < end) {
+		unsigned long bit_offset;
+		size_t len;
+
+		bit_offset = (start - dma->iova) >> PAGE_SHIFT;
+
+		for (len = 0; start + len < end; len += PAGE_SIZE) {
+			if (!IOPF_MAPPED_BITMAP_GET(dma,
+					bit_offset + (len >> PAGE_SHIFT)))
+				break;
+		}
+
+		if (len) {
+			i = 0;
+			list_for_each_entry(d, &iommu->domain_list, next) {
+				size_t unmapped;
+
+				if (gathers)
+					unmapped = iommu_unmap_fast(d->domain,
+								    start, len,
+								    &gathers[i++]);
+				else
+					unmapped = iommu_unmap(d->domain,
+							       start, len);
+
+				if (WARN_ON(unmapped != len))
+					goto out;
+			}
+
+			bitmap_clear(dma->iopf_mapped_bitmap,
+				     bit_offset, len >> PAGE_SHIFT);
+
+			cond_resched();
+		}
+
+		start += (len + PAGE_SIZE);
+	}
+
+out:
+	if (gathers) {
+		i = 0;
+		list_for_each_entry(d, &iommu->domain_list, next)
+			iommu_iotlb_sync(d->domain, &gathers[i++]);
+
+		kfree(gathers);
+	}
+}
+
 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
 {
 	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
@@ -3197,17 +3265,18 @@ static int vfio_iommu_type1_dma_map_iopf(struct iommu_fault *fault, void *data)
 
 	vaddr = iova - dma->iova + dma->vaddr;
 
-	if (vfio_pin_page_external(dma, vaddr, &pfn, true))
+	if (vfio_pin_page_external(dma, vaddr, &pfn, false))
 		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);
+		put_pfn(pfn, dma->prot);
 		goto out_invalid;
 	}
 
 	bitmap_set(dma->iopf_mapped_bitmap, bit_offset, 1);
 
+	put_pfn(pfn, dma->prot);
+
 out_success:
 	status = IOMMU_PAGE_RESP_SUCCESS;
 
@@ -3220,6 +3289,43 @@ static int vfio_iommu_type1_dma_map_iopf(struct iommu_fault *fault, void *data)
 	return 0;
 }
 
+static void mn_invalidate_range(struct mmu_notifier *mn, struct mm_struct *mm,
+				unsigned long start, unsigned long end)
+{
+	struct vfio_iommu *iommu = container_of(mn, struct vfio_iommu, mn);
+	struct rb_node *n;
+	int ret;
+
+	mutex_lock(&iommu->lock);
+
+	ret = vfio_wait_all_valid(iommu);
+	if (WARN_ON(ret < 0))
+		return;
+
+	for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
+		struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
+		unsigned long start_n, end_n;
+
+		if (end <= dma->vaddr || start >= dma->vaddr + dma->size)
+			continue;
+
+		start_n = ALIGN_DOWN(max_t(unsigned long, start, dma->vaddr),
+				     PAGE_SIZE);
+		end_n = ALIGN(min_t(unsigned long, end, dma->vaddr + dma->size),
+			      PAGE_SIZE);
+
+		vfio_unmap_partial_iopf(iommu, dma,
+					start_n - dma->vaddr + dma->iova,
+					end_n - dma->vaddr + dma->iova);
+	}
+
+	mutex_unlock(&iommu->lock);
+}
+
+static const struct mmu_notifier_ops vfio_iommu_type1_mn_ops = {
+	.invalidate_range	= mn_invalidate_range,
+};
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
 				   unsigned int cmd, unsigned long arg)
 {
-- 
2.19.1


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  parent reply	other threads:[~2021-04-09  3:49 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-09  3:44 [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 1/8] iommu: Evolve the device fault reporting framework Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:37     ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 2/8] vfio/type1: Add a page fault handler Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:38     ` Shenming Lu
2021-05-24 22:11       ` Alex Williamson
2021-05-27 11:16         ` Shenming Lu
2021-04-09  3:44 ` Shenming Lu [this message]
2021-05-18 18:58   ` [RFC PATCH v3 3/8] vfio/type1: Add an MMU notifier to avoid pinning Alex Williamson
2021-05-21  6:37     ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 4/8] vfio/type1: Pre-map more pages than requested in the IOPF handling Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:37     ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 5/8] vfio/type1: VFIO_IOMMU_ENABLE_IOPF Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:38     ` Shenming Lu
2021-05-24 22:11       ` Alex Williamson
2021-05-27 11:15         ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 6/8] vfio/type1: No need to statically pin and map if IOPF enabled Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:39     ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 7/8] vfio/type1: Add selective DMA faulting support Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  6:39     ` Shenming Lu
2021-04-09  3:44 ` [RFC PATCH v3 8/8] vfio: Add nested IOPF support Shenming Lu
2021-05-18 18:58   ` Alex Williamson
2021-05-21  7:59     ` Shenming Lu
2021-05-24 13:11       ` Shenming Lu
2021-05-24 22:11         ` Alex Williamson
2021-05-27 11:03           ` Shenming Lu
2021-05-27 11:18             ` Lu Baolu
2021-06-01  4:36               ` Shenming Lu
2021-04-26  1:41 ` [RFC PATCH v3 0/8] Add IOPF support for VFIO passthrough Shenming Lu
2021-05-11 11:30   ` Shenming Lu
2021-05-18 18:57 ` Alex Williamson
2021-05-21  6:37   ` Shenming Lu
2021-05-24 22:11     ` Alex Williamson
2021-05-27 11:25       ` Shenming Lu

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