xen/privcmd: Add support for Linux 64KB page granularity
The hypercall interface (as well as the toolstack) is always using 4KB page granularity. When the toolstack is asking for mapping a series of guest PFN in a batch, it expects to have the page map contiguously in its virtual memory. When Linux is using 64KB page granularity, the privcmd driver will have to map multiple Xen PFN in a single Linux page. Note that this solution works on page granularity which is a multiple of 4KB. Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
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@ -446,7 +446,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
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return -EINVAL;
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}
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nr_pages = m.num;
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nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);
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if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
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return -EINVAL;
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@ -494,7 +494,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
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goto out_unlock;
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}
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if (xen_feature(XENFEAT_auto_translated_physmap)) {
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ret = alloc_empty_pages(vma, m.num);
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ret = alloc_empty_pages(vma, nr_pages);
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if (ret < 0)
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goto out_unlock;
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} else
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@ -518,6 +518,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
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state.global_error = 0;
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state.version = version;
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BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);
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/* mmap_batch_fn guarantees ret == 0 */
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BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
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&pagelist, mmap_batch_fn, &state));
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@ -582,12 +583,13 @@ static void privcmd_close(struct vm_area_struct *vma)
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{
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struct page **pages = vma->vm_private_data;
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int numpgs = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
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int numgfns = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;
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int rc;
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if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
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return;
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rc = xen_unmap_domain_gfn_range(vma, numpgs, pages);
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rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);
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if (rc == 0)
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free_xenballooned_pages(numpgs, pages);
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else
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@ -38,31 +38,28 @@
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#include <xen/interface/xen.h>
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#include <xen/interface/memory.h>
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/* map fgfn of domid to lpfn in the current domain */
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static int map_foreign_page(unsigned long lpfn, unsigned long fgfn,
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unsigned int domid)
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typedef void (*xen_gfn_fn_t)(unsigned long gfn, void *data);
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/* Break down the pages in 4KB chunk and call fn for each gfn */
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static void xen_for_each_gfn(struct page **pages, unsigned nr_gfn,
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xen_gfn_fn_t fn, void *data)
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{
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int rc;
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struct xen_add_to_physmap_range xatp = {
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.domid = DOMID_SELF,
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.foreign_domid = domid,
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.size = 1,
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.space = XENMAPSPACE_gmfn_foreign,
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};
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xen_ulong_t idx = fgfn;
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xen_pfn_t gpfn = lpfn;
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int err = 0;
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unsigned long xen_pfn = 0;
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struct page *page;
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int i;
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set_xen_guest_handle(xatp.idxs, &idx);
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set_xen_guest_handle(xatp.gpfns, &gpfn);
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set_xen_guest_handle(xatp.errs, &err);
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rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
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return rc < 0 ? rc : err;
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for (i = 0; i < nr_gfn; i++) {
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if ((i % XEN_PFN_PER_PAGE) == 0) {
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page = pages[i / XEN_PFN_PER_PAGE];
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xen_pfn = page_to_xen_pfn(page);
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}
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fn(pfn_to_gfn(xen_pfn++), data);
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}
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}
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struct remap_data {
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xen_pfn_t *fgfn; /* foreign domain's gfn */
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int nr_fgfn; /* Number of foreign gfn left to map */
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pgprot_t prot;
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domid_t domid;
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struct vm_area_struct *vma;
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@ -71,24 +68,71 @@ struct remap_data {
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struct xen_remap_gfn_info *info;
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int *err_ptr;
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int mapped;
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/* Hypercall parameters */
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int h_errs[XEN_PFN_PER_PAGE];
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xen_ulong_t h_idxs[XEN_PFN_PER_PAGE];
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xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE];
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int h_iter; /* Iterator */
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};
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static void setup_hparams(unsigned long gfn, void *data)
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{
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struct remap_data *info = data;
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info->h_idxs[info->h_iter] = *info->fgfn;
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info->h_gpfns[info->h_iter] = gfn;
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info->h_errs[info->h_iter] = 0;
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info->h_iter++;
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info->fgfn++;
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}
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static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
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void *data)
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{
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struct remap_data *info = data;
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struct page *page = info->pages[info->index++];
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unsigned long pfn = page_to_pfn(page);
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pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
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int rc;
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pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
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int rc, nr_gfn;
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uint32_t i;
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struct xen_add_to_physmap_range xatp = {
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.domid = DOMID_SELF,
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.foreign_domid = info->domid,
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.space = XENMAPSPACE_gmfn_foreign,
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};
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rc = map_foreign_page(pfn, *info->fgfn, info->domid);
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*info->err_ptr++ = rc;
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if (!rc) {
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set_pte_at(info->vma->vm_mm, addr, ptep, pte);
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nr_gfn = min_t(typeof(info->nr_fgfn), XEN_PFN_PER_PAGE, info->nr_fgfn);
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info->nr_fgfn -= nr_gfn;
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info->h_iter = 0;
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xen_for_each_gfn(&page, nr_gfn, setup_hparams, info);
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BUG_ON(info->h_iter != nr_gfn);
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set_xen_guest_handle(xatp.idxs, info->h_idxs);
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set_xen_guest_handle(xatp.gpfns, info->h_gpfns);
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set_xen_guest_handle(xatp.errs, info->h_errs);
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xatp.size = nr_gfn;
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rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
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/* info->err_ptr expect to have one error status per Xen PFN */
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for (i = 0; i < nr_gfn; i++) {
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int err = (rc < 0) ? rc : info->h_errs[i];
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*(info->err_ptr++) = err;
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if (!err)
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info->mapped++;
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}
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info->fgfn++;
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/*
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* Note: The hypercall will return 0 in most of the case if even if
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* all the fgmfn are not mapped. We still have to update the pte
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* as the userspace may decide to continue.
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*/
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if (!rc)
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set_pte_at(info->vma->vm_mm, addr, ptep, pte);
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return 0;
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}
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@ -102,13 +146,14 @@ int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
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{
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int err;
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struct remap_data data;
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unsigned long range = nr << PAGE_SHIFT;
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unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << PAGE_SHIFT;
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/* Kept here for the purpose of making sure code doesn't break
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x86 PVOPS */
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BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
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data.fgfn = gfn;
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data.nr_fgfn = nr;
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data.prot = prot;
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data.domid = domid;
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data.vma = vma;
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@ -123,21 +168,20 @@ int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
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}
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EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
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static void unmap_gfn(unsigned long gfn, void *data)
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{
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struct xen_remove_from_physmap xrp;
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xrp.domid = DOMID_SELF;
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xrp.gpfn = gfn;
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(void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
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}
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int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
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int nr, struct page **pages)
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{
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int i;
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xen_for_each_gfn(pages, nr, unmap_gfn, NULL);
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for (i = 0; i < nr; i++) {
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struct xen_remove_from_physmap xrp;
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unsigned long pfn;
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pfn = page_to_pfn(pages[i]);
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xrp.domid = DOMID_SELF;
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xrp.gpfn = pfn;
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(void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);
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