xen/privcmd: add PRIVCMD_MMAPBATCH_V2 ioctl
PRIVCMD_MMAPBATCH_V2 extends PRIVCMD_MMAPBATCH with an additional field for reporting the error code for every frame that could not be mapped. libxc prefers PRIVCMD_MMAPBATCH_V2 over PRIVCMD_MMAPBATCH. Also expand PRIVCMD_MMAPBATCH to return appropriate error-encoding top nibble in the mfn array. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Andres Lagar-Cavilla
Konrad Rzeszutek Wilk
parent
69870a8478
commit
ceb90fa0a8
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@ -76,7 +76,7 @@ static void free_page_list(struct list_head *pages)
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*/
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static int gather_array(struct list_head *pagelist,
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unsigned nelem, size_t size,
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void __user *data)
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const void __user *data)
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{
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unsigned pageidx;
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void *pagedata;
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@ -246,61 +246,117 @@ struct mmap_batch_state {
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domid_t domain;
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unsigned long va;
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struct vm_area_struct *vma;
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int err;
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/* A tristate:
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* 0 for no errors
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* 1 if at least one error has happened (and no
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* -ENOENT errors have happened)
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* -ENOENT if at least 1 -ENOENT has happened.
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*/
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int global_error;
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/* An array for individual errors */
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int *err;
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xen_pfn_t __user *user;
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/* User-space mfn array to store errors in the second pass for V1. */
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xen_pfn_t __user *user_mfn;
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};
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static int mmap_batch_fn(void *data, void *state)
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{
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xen_pfn_t *mfnp = data;
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struct mmap_batch_state *st = state;
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int ret;
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if (xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
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st->vma->vm_page_prot, st->domain) < 0) {
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*mfnp |= 0xf0000000U;
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st->err++;
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ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
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st->vma->vm_page_prot, st->domain);
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/* Store error code for second pass. */
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*(st->err++) = ret;
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/* And see if it affects the global_error. */
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if (ret < 0) {
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if (ret == -ENOENT)
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st->global_error = -ENOENT;
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else {
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/* Record that at least one error has happened. */
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if (st->global_error == 0)
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st->global_error = 1;
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}
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}
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st->va += PAGE_SIZE;
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return 0;
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}
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static int mmap_return_errors(void *data, void *state)
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static int mmap_return_errors_v1(void *data, void *state)
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{
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xen_pfn_t *mfnp = data;
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struct mmap_batch_state *st = state;
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int err = *(st->err++);
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return put_user(*mfnp, st->user++);
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/*
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* V1 encodes the error codes in the 32bit top nibble of the
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* mfn (with its known limitations vis-a-vis 64 bit callers).
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*/
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*mfnp |= (err == -ENOENT) ?
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PRIVCMD_MMAPBATCH_PAGED_ERROR :
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PRIVCMD_MMAPBATCH_MFN_ERROR;
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return __put_user(*mfnp, st->user_mfn++);
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}
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static struct vm_operations_struct privcmd_vm_ops;
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static long privcmd_ioctl_mmap_batch(void __user *udata)
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static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
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{
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int ret;
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struct privcmd_mmapbatch m;
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struct privcmd_mmapbatch_v2 m;
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long nr_pages;
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LIST_HEAD(pagelist);
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int *err_array = NULL;
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struct mmap_batch_state state;
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if (!xen_initial_domain())
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return -EPERM;
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if (copy_from_user(&m, udata, sizeof(m)))
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return -EFAULT;
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switch (version) {
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case 1:
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if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
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return -EFAULT;
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/* Returns per-frame error in m.arr. */
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m.err = NULL;
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if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr)))
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return -EFAULT;
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break;
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case 2:
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if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
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return -EFAULT;
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/* Returns per-frame error code in m.err. */
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if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err))))
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return -EFAULT;
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break;
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default:
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return -EINVAL;
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}
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nr_pages = m.num;
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if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
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return -EINVAL;
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ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t),
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m.arr);
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ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
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if (ret || list_empty(&pagelist))
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if (ret)
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goto out;
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if (list_empty(&pagelist)) {
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ret = -EINVAL;
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goto out;
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}
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err_array = kcalloc(m.num, sizeof(int), GFP_KERNEL);
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if (err_array == NULL) {
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ret = -ENOMEM;
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goto out;
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}
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down_write(&mm->mmap_sem);
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@ -315,24 +371,34 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
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goto out;
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}
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state.domain = m.dom;
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state.vma = vma;
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state.va = m.addr;
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state.err = 0;
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state.domain = m.dom;
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state.vma = vma;
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state.va = m.addr;
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state.global_error = 0;
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state.err = err_array;
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ret = traverse_pages(m.num, sizeof(xen_pfn_t),
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&pagelist, mmap_batch_fn, &state);
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/* mmap_batch_fn guarantees ret == 0 */
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BUG_ON(traverse_pages(m.num, sizeof(xen_pfn_t),
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&pagelist, mmap_batch_fn, &state));
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up_write(&mm->mmap_sem);
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if (state.err > 0) {
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state.user = m.arr;
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if (state.global_error && (version == 1)) {
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/* Write back errors in second pass. */
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state.user_mfn = (xen_pfn_t *)m.arr;
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state.err = err_array;
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ret = traverse_pages(m.num, sizeof(xen_pfn_t),
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&pagelist,
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mmap_return_errors, &state);
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}
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&pagelist, mmap_return_errors_v1, &state);
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} else
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ret = __copy_to_user(m.err, err_array, m.num * sizeof(int));
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/* If we have not had any EFAULT-like global errors then set the global
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* error to -ENOENT if necessary. */
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if ((ret == 0) && (state.global_error == -ENOENT))
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ret = -ENOENT;
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out:
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kfree(err_array);
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free_page_list(&pagelist);
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return ret;
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@ -354,7 +420,11 @@ static long privcmd_ioctl(struct file *file,
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break;
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case IOCTL_PRIVCMD_MMAPBATCH:
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ret = privcmd_ioctl_mmap_batch(udata);
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ret = privcmd_ioctl_mmap_batch(udata, 1);
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break;
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case IOCTL_PRIVCMD_MMAPBATCH_V2:
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ret = privcmd_ioctl_mmap_batch(udata, 2);
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break;
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default:
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@ -58,13 +58,33 @@ struct privcmd_mmapbatch {
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int num; /* number of pages to populate */
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domid_t dom; /* target domain */
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__u64 addr; /* virtual address */
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xen_pfn_t __user *arr; /* array of mfns - top nibble set on err */
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xen_pfn_t __user *arr; /* array of mfns - or'd with
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PRIVCMD_MMAPBATCH_*_ERROR on err */
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};
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#define PRIVCMD_MMAPBATCH_MFN_ERROR 0xf0000000U
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#define PRIVCMD_MMAPBATCH_PAGED_ERROR 0x80000000U
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struct privcmd_mmapbatch_v2 {
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unsigned int num; /* number of pages to populate */
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domid_t dom; /* target domain */
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__u64 addr; /* virtual address */
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const xen_pfn_t __user *arr; /* array of mfns */
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int __user *err; /* array of error codes */
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};
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/*
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* @cmd: IOCTL_PRIVCMD_HYPERCALL
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* @arg: &privcmd_hypercall_t
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* Return: Value returned from execution of the specified hypercall.
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*
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* @cmd: IOCTL_PRIVCMD_MMAPBATCH_V2
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* @arg: &struct privcmd_mmapbatch_v2
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* Return: 0 on success (i.e., arg->err contains valid error codes for
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* each frame). On an error other than a failed frame remap, -1 is
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* returned and errno is set to EINVAL, EFAULT etc. As an exception,
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* if the operation was otherwise successful but any frame failed with
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* -ENOENT, then -1 is returned and errno is set to ENOENT.
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*/
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#define IOCTL_PRIVCMD_HYPERCALL \
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_IOC(_IOC_NONE, 'P', 0, sizeof(struct privcmd_hypercall))
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@ -72,5 +92,7 @@ struct privcmd_mmapbatch {
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_IOC(_IOC_NONE, 'P', 2, sizeof(struct privcmd_mmap))
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#define IOCTL_PRIVCMD_MMAPBATCH \
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_IOC(_IOC_NONE, 'P', 3, sizeof(struct privcmd_mmapbatch))
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#define IOCTL_PRIVCMD_MMAPBATCH_V2 \
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_IOC(_IOC_NONE, 'P', 4, sizeof(struct privcmd_mmapbatch_v2))
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#endif /* __LINUX_PUBLIC_PRIVCMD_H__ */
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