linux-kernel - [PATCH] vfio/iommu_type1: Mantainance a counter for non_pinned

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Date:   Mon, 25 Jan 2021 10:46:42 +0800
From:   Keqian Zhu <zhukeqian1@...wei.com>
To:     <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <kvm@...r.kernel.org>,
        <kvmarm@...ts.cs.columbia.edu>, <iommu@...ts.linux-foundation.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        Kirti Wankhede <kwankhede@...dia.com>,
        "Cornelia Huck" <cohuck@...hat.com>
CC:     Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        "Catalin Marinas" <catalin.marinas@....com>,
        Mark Rutland <mark.rutland@....com>,
        "James Morse" <james.morse@....com>,
        Robin Murphy <robin.murphy@....com>,
        "Joerg Roedel" <joro@...tes.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Alexios Zavras <alexios.zavras@...el.com>,
        <wanghaibin.wang@...wei.com>, <jiangkunkun@...wei.com>
Subject: [PATCH] vfio/iommu_type1: Mantainance a counter for non_pinned_groups

With this counter, we never need to traverse all groups to update
pinned_scope of vfio_iommu.

Suggested-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Keqian Zhu <zhukeqian1@...wei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 40 +++++----------------------------
 1 file changed, 5 insertions(+), 35 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 0b4dedaa9128..bb4bbcc79101 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -73,7 +73,7 @@ struct vfio_iommu {
 	bool			v2;
 	bool			nesting;
 	bool			dirty_page_tracking;
-	bool			pinned_page_dirty_scope;
+	uint64_t		num_non_pinned_groups;
 };
 
 struct vfio_domain {
@@ -148,7 +148,6 @@ static int put_pfn(unsigned long pfn, int prot);
 static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
 					       struct iommu_group *iommu_group);
 
-static void update_pinned_page_dirty_scope(struct vfio_iommu *iommu);
 /*
  * This code handles mapping and unmapping of user data buffers
  * into DMA'ble space using the IOMMU
@@ -714,7 +713,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
 	group = vfio_iommu_find_iommu_group(iommu, iommu_group);
 	if (!group->pinned_page_dirty_scope) {
 		group->pinned_page_dirty_scope = true;
-		update_pinned_page_dirty_scope(iommu);
+		iommu->num_non_pinned_groups--;
 	}
 
 	goto pin_done;
@@ -991,7 +990,7 @@ static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
 	 * mark all pages dirty if any IOMMU capable device is not able
 	 * to report dirty pages and all pages are pinned and mapped.
 	 */
-	if (!iommu->pinned_page_dirty_scope && dma->iommu_mapped)
+	if (iommu->num_non_pinned_groups && dma->iommu_mapped)
 		bitmap_set(dma->bitmap, 0, nbits);
 
 	if (shift) {
@@ -1622,33 +1621,6 @@ static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
 	return group;
 }
 
-static void update_pinned_page_dirty_scope(struct vfio_iommu *iommu)
-{
-	struct vfio_domain *domain;
-	struct vfio_group *group;
-
-	list_for_each_entry(domain, &iommu->domain_list, next) {
-		list_for_each_entry(group, &domain->group_list, next) {
-			if (!group->pinned_page_dirty_scope) {
-				iommu->pinned_page_dirty_scope = false;
-				return;
-			}
-		}
-	}
-
-	if (iommu->external_domain) {
-		domain = iommu->external_domain;
-		list_for_each_entry(group, &domain->group_list, next) {
-			if (!group->pinned_page_dirty_scope) {
-				iommu->pinned_page_dirty_scope = false;
-				return;
-			}
-		}
-	}
-
-	iommu->pinned_page_dirty_scope = true;
-}
-
 static bool vfio_iommu_has_sw_msi(struct list_head *group_resv_regions,
 				  phys_addr_t *base)
 {
@@ -2057,8 +2029,6 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 			 * addition of a dirty tracking group.
 			 */
 			group->pinned_page_dirty_scope = true;
-			if (!iommu->pinned_page_dirty_scope)
-				update_pinned_page_dirty_scope(iommu);
 			mutex_unlock(&iommu->lock);
 
 			return 0;
@@ -2188,7 +2158,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	 * demotes the iommu scope until it declares itself dirty tracking
 	 * capable via the page pinning interface.
 	 */
-	iommu->pinned_page_dirty_scope = false;
+	iommu->num_non_pinned_groups++;
 	mutex_unlock(&iommu->lock);
 	vfio_iommu_resv_free(&group_resv_regions);
 
@@ -2416,7 +2386,7 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
 	 * to be promoted.
 	 */
 	if (update_dirty_scope)
-		update_pinned_page_dirty_scope(iommu);
+		iommu->num_non_pinned_groups--;
 	mutex_unlock(&iommu->lock);
 }
 
-- 
2.19.1