[PATCH v3 03/18] KVM: PPC: Account TCE pages in locked_vm

[Alexey Kardashevskiy]

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
 arch/powerpc/kvm/book3s_64_vio.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 516f2ee..48b7ed4 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -45,18 +45,48 @@ static long kvmppc_stt_npages(unsigned long window_size)
                     * sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
 }
 
+/*
+ * Checks ulimit in order not to let the user space to pin all
+ * available memory for TCE tables.
+ */
+static long kvmppc_account_memlimit(long npages)
+{
+       unsigned long ret = 0, locked, lock_limit;
+
+       if (!current->mm)
+               return -ESRCH; /* process exited */
+
+       down_write(&current->mm->mmap_sem);
+       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 {
+               current->mm->locked_vm += npages;
+       }
+       up_write(&current->mm->mmap_sem);
+
+       return ret;
+}
+
 static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt)
 {
        struct kvm *kvm = stt->kvm;
        int i;
+       long npages = kvmppc_stt_npages(stt->window_size);
 
        mutex_lock(&kvm->lock);
        list_del(&stt->list);
-       for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++)
+       for (i = 0; i < npages; i++)
                __free_page(stt->pages[i]);
+
        kfree(stt);
        mutex_unlock(&kvm->lock);
 
+       kvmppc_account_memlimit(-(npages + 1));
+
        kvm_put_kvm(kvm);
 }
 
@@ -112,6 +142,9 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
        }
 
        npages = kvmppc_stt_npages(args->window_size);
+       ret = kvmppc_account_memlimit(npages + 1);
+       if (ret)
+               goto fail;
 
        stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
                      GFP_KERNEL);
-- 
2.0.0

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