diff options
Diffstat (limited to 'drivers/vfio')
| -rw-r--r-- | drivers/vfio/vfio_iommu_spapr_tce.c | 82 |
1 files changed, 63 insertions, 19 deletions
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index 64300ccb05db..6e2e15fdb0df 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -29,6 +29,51 @@ static void tce_iommu_detach_group(void *iommu_data, struct iommu_group *iommu_group); +static long try_increment_locked_vm(long npages) +{ + long ret = 0, locked, lock_limit; + + if (!current || !current->mm) + return -ESRCH; /* process exited */ + + if (!npages) + return 0; + + down_write(¤t->mm->mmap_sem); + locked = current->mm->locked_vm + npages; + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) + ret = -ENOMEM; + else + current->mm->locked_vm += npages; + + pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid, + npages << PAGE_SHIFT, + current->mm->locked_vm << PAGE_SHIFT, + rlimit(RLIMIT_MEMLOCK), + ret ? " - exceeded" : ""); + + up_write(¤t->mm->mmap_sem); + + return ret; +} + +static void decrement_locked_vm(long npages) +{ + if (!current || !current->mm || !npages) + return; /* process exited */ + + down_write(¤t->mm->mmap_sem); + if (WARN_ON_ONCE(npages > current->mm->locked_vm)) + npages = current->mm->locked_vm; + current->mm->locked_vm -= npages; + pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid, + npages << PAGE_SHIFT, + current->mm->locked_vm << PAGE_SHIFT, + rlimit(RLIMIT_MEMLOCK)); + up_write(¤t->mm->mmap_sem); +} + /* * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation * @@ -45,6 +90,7 @@ struct tce_container { struct mutex lock; struct iommu_table *tbl; bool enabled; + unsigned long locked_pages; }; static bool tce_page_is_contained(struct page *page, unsigned page_shift) @@ -60,7 +106,7 @@ static bool tce_page_is_contained(struct page *page, unsigned page_shift) static int tce_iommu_enable(struct tce_container *container) { int ret = 0; - unsigned long locked, lock_limit, npages; + unsigned long locked; struct iommu_table *tbl = container->tbl; if (!container->tbl) @@ -89,21 +135,22 @@ static int tce_iommu_enable(struct tce_container *container) * Also we don't have a nice way to fail on H_PUT_TCE due to ulimits, * that would effectively kill the guest at random points, much better * enforcing the limit based on the max that the guest can map. + * + * Unfortunately at the moment it counts whole tables, no matter how + * much memory the guest has. I.e. for 4GB guest and 4 IOMMU groups + * each with 2GB DMA window, 8GB will be counted here. The reason for + * this is that we cannot tell here the amount of RAM used by the guest + * as this information is only available from KVM and VFIO is + * KVM agnostic. */ - down_write(¤t->mm->mmap_sem); - npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT; - locked = current->mm->locked_vm + npages; - lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) { - pr_warn("RLIMIT_MEMLOCK (%ld) exceeded\n", - rlimit(RLIMIT_MEMLOCK)); - ret = -ENOMEM; - } else { + locked = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT; + ret = try_increment_locked_vm(locked); + if (ret) + return ret; - current->mm->locked_vm += npages; - container->enabled = true; - } - up_write(¤t->mm->mmap_sem); + container->locked_pages = locked; + + container->enabled = true; return ret; } @@ -115,13 +162,10 @@ static void tce_iommu_disable(struct tce_container *container) container->enabled = false; - if (!container->tbl || !current->mm) + if (!current->mm) return; - down_write(¤t->mm->mmap_sem); - current->mm->locked_vm -= (container->tbl->it_size << - container->tbl->it_page_shift) >> PAGE_SHIFT; - up_write(¤t->mm->mmap_sem); + decrement_locked_vm(container->locked_pages); } static void *tce_iommu_open(unsigned long arg) |