From 89c29def6b0101fff66a3d74d0178b844f88d732 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Sat, 2 Jun 2018 08:41:44 -0600 Subject: [PATCH] Revert "vfio/type1: Improve memory pinning process for raw PFN mapping" MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Bisection by Amadeusz Sławiński implicates this commit leading to bad page state issues after VM shutdown, likely due to unbalanced page references. The original commit was intended only as a performance improvement, therefore revert for offline rework. Link: https://lkml.org/lkml/2018/6/2/97 Fixes: 356e88ebe447 ("vfio/type1: Improve memory pinning process for raw PFN mapping") Cc: Jason Cai (Xiang Feng) Reported-by: Amadeusz Sławiński Signed-off-by: Alex Williamson --- drivers/vfio/vfio_iommu_type1.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 5c212bf29640..3c082451ab1a 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -404,6 +404,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, { unsigned long pfn = 0; long ret, pinned = 0, lock_acct = 0; + bool rsvd; dma_addr_t iova = vaddr - dma->vaddr + dma->iova; /* This code path is only user initiated */ @@ -414,23 +415,14 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, if (ret) return ret; - if (is_invalid_reserved_pfn(*pfn_base)) { - struct vm_area_struct *vma; - - down_read(¤t->mm->mmap_sem); - vma = find_vma_intersection(current->mm, vaddr, vaddr + 1); - pinned = min_t(long, npage, vma_pages(vma)); - up_read(¤t->mm->mmap_sem); - return pinned; - } - pinned++; + rsvd = is_invalid_reserved_pfn(*pfn_base); /* * Reserved pages aren't counted against the user, externally pinned * pages are already counted against the user. */ - if (!vfio_find_vpfn(dma, iova)) { + if (!rsvd && !vfio_find_vpfn(dma, iova)) { if (!lock_cap && current->mm->locked_vm + 1 > limit) { put_pfn(*pfn_base, dma->prot); pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__, @@ -450,12 +442,13 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, if (ret) break; - if (pfn != *pfn_base + pinned) { + if (pfn != *pfn_base + pinned || + rsvd != is_invalid_reserved_pfn(pfn)) { put_pfn(pfn, dma->prot); break; } - if (!vfio_find_vpfn(dma, iova)) { + if (!rsvd && !vfio_find_vpfn(dma, iova)) { if (!lock_cap && current->mm->locked_vm + lock_acct + 1 > limit) { put_pfn(pfn, dma->prot); @@ -473,8 +466,10 @@ out: unpin_out: if (ret) { - for (pfn = *pfn_base ; pinned ; pfn++, pinned--) - put_pfn(pfn, dma->prot); + if (!rsvd) { + for (pfn = *pfn_base ; pinned ; pfn++, pinned--) + put_pfn(pfn, dma->prot); + } return ret; } -- 2.30.2