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Revert "vfio/type1: Improve memory pinning process for raw PFN mapping"

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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: 356e88ebe4 ("vfio/type1: Improve memory pinning process for raw PFN mapping")
Cc: Jason Cai (Xiang Feng) <jason.cai@linux.alibaba.com>
Reported-by: Amadeusz Sławiński <amade@asmblr.net>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2018-06-02 08:41:44 -06:00
parent 0512e01345
commit 89c29def6b
1 changed files with 10 additions and 15 deletions
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25
drivers/vfio/vfio_iommu_type1.c
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@ -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(&current->mm->mmap_sem);
vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
pinned = min_t(long, npage, vma_pages(vma));
up_read(&current->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 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
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;
}