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path: root/drivers/xen/privcmd.c
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-rw-r--r--drivers/xen/privcmd.c679
1 files changed, 679 insertions, 0 deletions
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
new file mode 100644
index 000000000..5a296161d
--- /dev/null
+++ b/drivers/xen/privcmd.c
@@ -0,0 +1,679 @@
+/******************************************************************************
+ * privcmd.c
+ *
+ * Interface to privileged domain-0 commands.
+ *
+ * Copyright (c) 2002-2004, K A Fraser, B Dragovic
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/uaccess.h>
+#include <linux/swap.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+#include <linux/seq_file.h>
+#include <linux/miscdevice.h>
+
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/tlb.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/xen.h>
+#include <xen/privcmd.h>
+#include <xen/interface/xen.h>
+#include <xen/features.h>
+#include <xen/page.h>
+#include <xen/xen-ops.h>
+#include <xen/balloon.h>
+
+#include "privcmd.h"
+
+MODULE_LICENSE("GPL");
+
+#define PRIV_VMA_LOCKED ((void *)1)
+
+static int privcmd_vma_range_is_mapped(
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ unsigned long nr_pages);
+
+static long privcmd_ioctl_hypercall(void __user *udata)
+{
+ struct privcmd_hypercall hypercall;
+ long ret;
+
+ if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
+ return -EFAULT;
+
+ xen_preemptible_hcall_begin();
+ ret = privcmd_call(hypercall.op,
+ hypercall.arg[0], hypercall.arg[1],
+ hypercall.arg[2], hypercall.arg[3],
+ hypercall.arg[4]);
+ xen_preemptible_hcall_end();
+
+ return ret;
+}
+
+static void free_page_list(struct list_head *pages)
+{
+ struct page *p, *n;
+
+ list_for_each_entry_safe(p, n, pages, lru)
+ __free_page(p);
+
+ INIT_LIST_HEAD(pages);
+}
+
+/*
+ * Given an array of items in userspace, return a list of pages
+ * containing the data. If copying fails, either because of memory
+ * allocation failure or a problem reading user memory, return an
+ * error code; its up to the caller to dispose of any partial list.
+ */
+static int gather_array(struct list_head *pagelist,
+ unsigned nelem, size_t size,
+ const void __user *data)
+{
+ unsigned pageidx;
+ void *pagedata;
+ int ret;
+
+ if (size > PAGE_SIZE)
+ return 0;
+
+ pageidx = PAGE_SIZE;
+ pagedata = NULL; /* quiet, gcc */
+ while (nelem--) {
+ if (pageidx > PAGE_SIZE-size) {
+ struct page *page = alloc_page(GFP_KERNEL);
+
+ ret = -ENOMEM;
+ if (page == NULL)
+ goto fail;
+
+ pagedata = page_address(page);
+
+ list_add_tail(&page->lru, pagelist);
+ pageidx = 0;
+ }
+
+ ret = -EFAULT;
+ if (copy_from_user(pagedata + pageidx, data, size))
+ goto fail;
+
+ data += size;
+ pageidx += size;
+ }
+
+ ret = 0;
+
+fail:
+ return ret;
+}
+
+/*
+ * Call function "fn" on each element of the array fragmented
+ * over a list of pages.
+ */
+static int traverse_pages(unsigned nelem, size_t size,
+ struct list_head *pos,
+ int (*fn)(void *data, void *state),
+ void *state)
+{
+ void *pagedata;
+ unsigned pageidx;
+ int ret = 0;
+
+ BUG_ON(size > PAGE_SIZE);
+
+ pageidx = PAGE_SIZE;
+ pagedata = NULL; /* hush, gcc */
+
+ while (nelem--) {
+ if (pageidx > PAGE_SIZE-size) {
+ struct page *page;
+ pos = pos->next;
+ page = list_entry(pos, struct page, lru);
+ pagedata = page_address(page);
+ pageidx = 0;
+ }
+
+ ret = (*fn)(pagedata + pageidx, state);
+ if (ret)
+ break;
+ pageidx += size;
+ }
+
+ return ret;
+}
+
+/*
+ * Similar to traverse_pages, but use each page as a "block" of
+ * data to be processed as one unit.
+ */
+static int traverse_pages_block(unsigned nelem, size_t size,
+ struct list_head *pos,
+ int (*fn)(void *data, int nr, void *state),
+ void *state)
+{
+ void *pagedata;
+ unsigned pageidx;
+ int ret = 0;
+
+ BUG_ON(size > PAGE_SIZE);
+
+ pageidx = PAGE_SIZE;
+
+ while (nelem) {
+ int nr = (PAGE_SIZE/size);
+ struct page *page;
+ if (nr > nelem)
+ nr = nelem;
+ pos = pos->next;
+ page = list_entry(pos, struct page, lru);
+ pagedata = page_address(page);
+ ret = (*fn)(pagedata, nr, state);
+ if (ret)
+ break;
+ nelem -= nr;
+ }
+
+ return ret;
+}
+
+struct mmap_mfn_state {
+ unsigned long va;
+ struct vm_area_struct *vma;
+ domid_t domain;
+};
+
+static int mmap_mfn_range(void *data, void *state)
+{
+ struct privcmd_mmap_entry *msg = data;
+ struct mmap_mfn_state *st = state;
+ struct vm_area_struct *vma = st->vma;
+ int rc;
+
+ /* Do not allow range to wrap the address space. */
+ if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
+ ((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
+ return -EINVAL;
+
+ /* Range chunks must be contiguous in va space. */
+ if ((msg->va != st->va) ||
+ ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
+ return -EINVAL;
+
+ rc = xen_remap_domain_mfn_range(vma,
+ msg->va & PAGE_MASK,
+ msg->mfn, msg->npages,
+ vma->vm_page_prot,
+ st->domain, NULL);
+ if (rc < 0)
+ return rc;
+
+ st->va += msg->npages << PAGE_SHIFT;
+
+ return 0;
+}
+
+static long privcmd_ioctl_mmap(void __user *udata)
+{
+ struct privcmd_mmap mmapcmd;
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ int rc;
+ LIST_HEAD(pagelist);
+ struct mmap_mfn_state state;
+
+ /* We only support privcmd_ioctl_mmap_batch for auto translated. */
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return -ENOSYS;
+
+ if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
+ return -EFAULT;
+
+ rc = gather_array(&pagelist,
+ mmapcmd.num, sizeof(struct privcmd_mmap_entry),
+ mmapcmd.entry);
+
+ if (rc || list_empty(&pagelist))
+ goto out;
+
+ down_write(&mm->mmap_sem);
+
+ {
+ struct page *page = list_first_entry(&pagelist,
+ struct page, lru);
+ struct privcmd_mmap_entry *msg = page_address(page);
+
+ vma = find_vma(mm, msg->va);
+ rc = -EINVAL;
+
+ if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
+ goto out_up;
+ vma->vm_private_data = PRIV_VMA_LOCKED;
+ }
+
+ state.va = vma->vm_start;
+ state.vma = vma;
+ state.domain = mmapcmd.dom;
+
+ rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
+ &pagelist,
+ mmap_mfn_range, &state);
+
+
+out_up:
+ up_write(&mm->mmap_sem);
+
+out:
+ free_page_list(&pagelist);
+
+ return rc;
+}
+
+struct mmap_batch_state {
+ domid_t domain;
+ unsigned long va;
+ struct vm_area_struct *vma;
+ int index;
+ /* A tristate:
+ * 0 for no errors
+ * 1 if at least one error has happened (and no
+ * -ENOENT errors have happened)
+ * -ENOENT if at least 1 -ENOENT has happened.
+ */
+ int global_error;
+ int version;
+
+ /* User-space mfn array to store errors in the second pass for V1. */
+ xen_pfn_t __user *user_mfn;
+ /* User-space int array to store errors in the second pass for V2. */
+ int __user *user_err;
+};
+
+/* auto translated dom0 note: if domU being created is PV, then mfn is
+ * mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP).
+ */
+static int mmap_batch_fn(void *data, int nr, void *state)
+{
+ xen_pfn_t *mfnp = data;
+ struct mmap_batch_state *st = state;
+ struct vm_area_struct *vma = st->vma;
+ struct page **pages = vma->vm_private_data;
+ struct page **cur_pages = NULL;
+ int ret;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ cur_pages = &pages[st->index];
+
+ BUG_ON(nr < 0);
+ ret = xen_remap_domain_mfn_array(st->vma, st->va & PAGE_MASK, mfnp, nr,
+ (int *)mfnp, st->vma->vm_page_prot,
+ st->domain, cur_pages);
+
+ /* Adjust the global_error? */
+ if (ret != nr) {
+ if (ret == -ENOENT)
+ st->global_error = -ENOENT;
+ else {
+ /* Record that at least one error has happened. */
+ if (st->global_error == 0)
+ st->global_error = 1;
+ }
+ }
+ st->va += PAGE_SIZE * nr;
+ st->index += nr;
+
+ return 0;
+}
+
+static int mmap_return_error(int err, struct mmap_batch_state *st)
+{
+ int ret;
+
+ if (st->version == 1) {
+ if (err) {
+ xen_pfn_t mfn;
+
+ ret = get_user(mfn, st->user_mfn);
+ if (ret < 0)
+ return ret;
+ /*
+ * V1 encodes the error codes in the 32bit top
+ * nibble of the mfn (with its known
+ * limitations vis-a-vis 64 bit callers).
+ */
+ mfn |= (err == -ENOENT) ?
+ PRIVCMD_MMAPBATCH_PAGED_ERROR :
+ PRIVCMD_MMAPBATCH_MFN_ERROR;
+ return __put_user(mfn, st->user_mfn++);
+ } else
+ st->user_mfn++;
+ } else { /* st->version == 2 */
+ if (err)
+ return __put_user(err, st->user_err++);
+ else
+ st->user_err++;
+ }
+
+ return 0;
+}
+
+static int mmap_return_errors(void *data, int nr, void *state)
+{
+ struct mmap_batch_state *st = state;
+ int *errs = data;
+ int i;
+ int ret;
+
+ for (i = 0; i < nr; i++) {
+ ret = mmap_return_error(errs[i], st);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
+/* Allocate pfns that are then mapped with gmfns from foreign domid. Update
+ * the vma with the page info to use later.
+ * Returns: 0 if success, otherwise -errno
+ */
+static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
+{
+ int rc;
+ struct page **pages;
+
+ pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
+ if (pages == NULL)
+ return -ENOMEM;
+
+ rc = alloc_xenballooned_pages(numpgs, pages, 0);
+ if (rc != 0) {
+ pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
+ numpgs, rc);
+ kfree(pages);
+ return -ENOMEM;
+ }
+ BUG_ON(vma->vm_private_data != NULL);
+ vma->vm_private_data = pages;
+
+ return 0;
+}
+
+static struct vm_operations_struct privcmd_vm_ops;
+
+static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
+{
+ int ret;
+ struct privcmd_mmapbatch_v2 m;
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long nr_pages;
+ LIST_HEAD(pagelist);
+ struct mmap_batch_state state;
+
+ switch (version) {
+ case 1:
+ if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
+ return -EFAULT;
+ /* Returns per-frame error in m.arr. */
+ m.err = NULL;
+ if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr)))
+ return -EFAULT;
+ break;
+ case 2:
+ if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
+ return -EFAULT;
+ /* Returns per-frame error code in m.err. */
+ if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err))))
+ return -EFAULT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ nr_pages = m.num;
+ if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
+ return -EINVAL;
+
+ ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
+
+ if (ret)
+ goto out;
+ if (list_empty(&pagelist)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (version == 2) {
+ /* Zero error array now to only copy back actual errors. */
+ if (clear_user(m.err, sizeof(int) * m.num)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ }
+
+ down_write(&mm->mmap_sem);
+
+ vma = find_vma(mm, m.addr);
+ if (!vma ||
+ vma->vm_ops != &privcmd_vm_ops) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ /*
+ * Caller must either:
+ *
+ * Map the whole VMA range, which will also allocate all the
+ * pages required for the auto_translated_physmap case.
+ *
+ * Or
+ *
+ * Map unmapped holes left from a previous map attempt (e.g.,
+ * because those foreign frames were previously paged out).
+ */
+ if (vma->vm_private_data == NULL) {
+ if (m.addr != vma->vm_start ||
+ m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ ret = alloc_empty_pages(vma, m.num);
+ if (ret < 0)
+ goto out_unlock;
+ } else
+ vma->vm_private_data = PRIV_VMA_LOCKED;
+ } else {
+ if (m.addr < vma->vm_start ||
+ m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ }
+
+ state.domain = m.dom;
+ state.vma = vma;
+ state.va = m.addr;
+ state.index = 0;
+ state.global_error = 0;
+ state.version = version;
+
+ /* mmap_batch_fn guarantees ret == 0 */
+ BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
+ &pagelist, mmap_batch_fn, &state));
+
+ up_write(&mm->mmap_sem);
+
+ if (state.global_error) {
+ /* Write back errors in second pass. */
+ state.user_mfn = (xen_pfn_t *)m.arr;
+ state.user_err = m.err;
+ ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
+ &pagelist, mmap_return_errors, &state);
+ } else
+ ret = 0;
+
+ /* If we have not had any EFAULT-like global errors then set the global
+ * error to -ENOENT if necessary. */
+ if ((ret == 0) && (state.global_error == -ENOENT))
+ ret = -ENOENT;
+
+out:
+ free_page_list(&pagelist);
+ return ret;
+
+out_unlock:
+ up_write(&mm->mmap_sem);
+ goto out;
+}
+
+static long privcmd_ioctl(struct file *file,
+ unsigned int cmd, unsigned long data)
+{
+ int ret = -ENOSYS;
+ void __user *udata = (void __user *) data;
+
+ switch (cmd) {
+ case IOCTL_PRIVCMD_HYPERCALL:
+ ret = privcmd_ioctl_hypercall(udata);
+ break;
+
+ case IOCTL_PRIVCMD_MMAP:
+ ret = privcmd_ioctl_mmap(udata);
+ break;
+
+ case IOCTL_PRIVCMD_MMAPBATCH:
+ ret = privcmd_ioctl_mmap_batch(udata, 1);
+ break;
+
+ case IOCTL_PRIVCMD_MMAPBATCH_V2:
+ ret = privcmd_ioctl_mmap_batch(udata, 2);
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static void privcmd_close(struct vm_area_struct *vma)
+{
+ struct page **pages = vma->vm_private_data;
+ int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ int rc;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
+ return;
+
+ rc = xen_unmap_domain_mfn_range(vma, numpgs, pages);
+ if (rc == 0)
+ free_xenballooned_pages(numpgs, pages);
+ else
+ pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",
+ numpgs, rc);
+ kfree(pages);
+}
+
+static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
+ vma, vma->vm_start, vma->vm_end,
+ vmf->pgoff, vmf->virtual_address);
+
+ return VM_FAULT_SIGBUS;
+}
+
+static struct vm_operations_struct privcmd_vm_ops = {
+ .close = privcmd_close,
+ .fault = privcmd_fault
+};
+
+static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ /* DONTCOPY is essential for Xen because copy_page_range doesn't know
+ * how to recreate these mappings */
+ vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTCOPY |
+ VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_ops = &privcmd_vm_ops;
+ vma->vm_private_data = NULL;
+
+ return 0;
+}
+
+/*
+ * For MMAPBATCH*. This allows asserting the singleshot mapping
+ * on a per pfn/pte basis. Mapping calls that fail with ENOENT
+ * can be then retried until success.
+ */
+static int is_mapped_fn(pte_t *pte, struct page *pmd_page,
+ unsigned long addr, void *data)
+{
+ return pte_none(*pte) ? 0 : -EBUSY;
+}
+
+static int privcmd_vma_range_is_mapped(
+ struct vm_area_struct *vma,
+ unsigned long addr,
+ unsigned long nr_pages)
+{
+ return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT,
+ is_mapped_fn, NULL) != 0;
+}
+
+const struct file_operations xen_privcmd_fops = {
+ .owner = THIS_MODULE,
+ .unlocked_ioctl = privcmd_ioctl,
+ .mmap = privcmd_mmap,
+};
+EXPORT_SYMBOL_GPL(xen_privcmd_fops);
+
+static struct miscdevice privcmd_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "xen/privcmd",
+ .fops = &xen_privcmd_fops,
+};
+
+static int __init privcmd_init(void)
+{
+ int err;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ err = misc_register(&privcmd_dev);
+ if (err != 0) {
+ pr_err("Could not register Xen privcmd device\n");
+ return err;
+ }
+ return 0;
+}
+
+static void __exit privcmd_exit(void)
+{
+ misc_deregister(&privcmd_dev);
+}
+
+module_init(privcmd_init);
+module_exit(privcmd_exit);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-16 15:04:29 +0000