From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198
---
kernel/drivers/vfio/vfio_iommu_type1.c | 43 +++++++++++++++----------------------------
1 files changed, 15 insertions(+), 28 deletions(-)
diff --git a/kernel/drivers/vfio/vfio_iommu_type1.c b/kernel/drivers/vfio/vfio_iommu_type1.c
index ce50ca9..9b01f88 100644
--- a/kernel/drivers/vfio/vfio_iommu_type1.c
+++ b/kernel/drivers/vfio/vfio_iommu_type1.c
@@ -96,6 +96,7 @@
struct task_struct *task;
struct rb_root pfn_list; /* Ex-user pinned pfn list */
unsigned long *bitmap;
+ struct mm_struct *mm;
};
struct vfio_batch {
@@ -391,8 +392,8 @@
if (!npage)
return 0;
- mm = async ? get_task_mm(dma->task) : dma->task->mm;
- if (!mm)
+ mm = dma->mm;
+ if (async && !mmget_not_zero(mm))
return -ESRCH; /* process exited */
ret = mmap_write_lock_killable(mm);
@@ -666,8 +667,8 @@
struct mm_struct *mm;
int ret;
- mm = get_task_mm(dma->task);
- if (!mm)
+ mm = dma->mm;
+ if (!mmget_not_zero(mm))
return -ENODEV;
ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages);
@@ -677,7 +678,7 @@
ret = 0;
if (do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
- ret = vfio_lock_acct(dma, 1, true);
+ ret = vfio_lock_acct(dma, 1, false);
if (ret) {
put_pfn(*pfn_base, dma->prot);
if (ret == -ENOMEM)
@@ -1031,6 +1032,7 @@
vfio_unmap_unpin(iommu, dma, true);
vfio_unlink_dma(iommu, dma);
put_task_struct(dma->task);
+ mmdrop(dma->mm);
vfio_dma_bitmap_free(dma);
kfree(dma);
iommu->dma_avail++;
@@ -1452,29 +1454,15 @@
* against the locked memory limit and we need to be able to do both
* outside of this call path as pinning can be asynchronous via the
* external interfaces for mdev devices. RLIMIT_MEMLOCK requires a
- * task_struct and VM locked pages requires an mm_struct, however
- * holding an indefinite mm reference is not recommended, therefore we
- * only hold a reference to a task. We could hold a reference to
- * current, however QEMU uses this call path through vCPU threads,
- * which can be killed resulting in a NULL mm and failure in the unmap
- * path when called via a different thread. Avoid this problem by
- * using the group_leader as threads within the same group require
- * both CLONE_THREAD and CLONE_VM and will therefore use the same
- * mm_struct.
- *
- * Previously we also used the task for testing CAP_IPC_LOCK at the
- * time of pinning and accounting, however has_capability() makes use
- * of real_cred, a copy-on-write field, so we can't guarantee that it
- * matches group_leader, or in fact that it might not change by the
- * time it's evaluated. If a process were to call MAP_DMA with
- * CAP_IPC_LOCK but later drop it, it doesn't make sense that they
- * possibly see different results for an iommu_mapped vfio_dma vs
- * externally mapped. Therefore track CAP_IPC_LOCK in vfio_dma at the
- * time of calling MAP_DMA.
+ * task_struct. Save the group_leader so that all DMA tracking uses
+ * the same task, to make debugging easier. VM locked pages requires
+ * an mm_struct, so grab the mm in case the task dies.
*/
get_task_struct(current->group_leader);
dma->task = current->group_leader;
dma->lock_cap = capable(CAP_IPC_LOCK);
+ dma->mm = current->mm;
+ mmgrab(dma->mm);
dma->pfn_list = RB_ROOT;
@@ -2671,7 +2659,7 @@
static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
struct vfio_info_cap *caps)
{
- struct vfio_iommu_type1_info_cap_migration cap_mig;
+ struct vfio_iommu_type1_info_cap_migration cap_mig = {};
cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
cap_mig.header.version = 1;
@@ -2998,9 +2986,8 @@
!(dma->prot & IOMMU_READ))
return -EPERM;
- mm = get_task_mm(dma->task);
-
- if (!mm)
+ mm = dma->mm;
+ if (!mmget_not_zero(mm))
return -EPERM;
if (kthread)
--
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