drivers/xen/xlate_mmu.c

Source file repositories/reference/linux-study-clean/drivers/xen/xlate_mmu.c

File Facts

System
Linux kernel
Corpus path
drivers/xen/xlate_mmu.c
Extension
.c
Size
7924 bytes
Lines
296
Domain
Driver Families
Bucket
drivers/xen
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct remap_data {
	xen_pfn_t *fgfn; /* foreign domain's gfn */
	int nr_fgfn; /* Number of foreign gfn left to map */
	pgprot_t prot;
	domid_t  domid;
	struct vm_area_struct *vma;
	int index;
	struct page **pages;
	struct xen_remap_gfn_info *info;
	int *err_ptr;
	int mapped;

	/* Hypercall parameters */
	int h_errs[XEN_PFN_PER_PAGE];
	xen_ulong_t h_idxs[XEN_PFN_PER_PAGE];
	xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE];

	int h_iter;	/* Iterator */
};

static void setup_hparams(unsigned long gfn, void *data)
{
	struct remap_data *info = data;

	info->h_idxs[info->h_iter] = *info->fgfn;
	info->h_gpfns[info->h_iter] = gfn;
	info->h_errs[info->h_iter] = 0;

	info->h_iter++;
	info->fgfn++;
}

static int remap_pte_fn(pte_t *ptep, unsigned long addr, void *data)
{
	struct remap_data *info = data;
	struct page *page = info->pages[info->index++];
	pte_t pte = pte_mkspecial(pfn_pte(page_to_pfn(page), info->prot));
	int rc, nr_gfn;
	uint32_t i;
	struct xen_add_to_physmap_range xatp = {
		.domid = DOMID_SELF,
		.foreign_domid = info->domid,
		.space = XENMAPSPACE_gmfn_foreign,
	};

	nr_gfn = min_t(typeof(info->nr_fgfn), XEN_PFN_PER_PAGE, info->nr_fgfn);
	info->nr_fgfn -= nr_gfn;

	info->h_iter = 0;
	xen_for_each_gfn(&page, nr_gfn, setup_hparams, info);
	BUG_ON(info->h_iter != nr_gfn);

	set_xen_guest_handle(xatp.idxs, info->h_idxs);
	set_xen_guest_handle(xatp.gpfns, info->h_gpfns);
	set_xen_guest_handle(xatp.errs, info->h_errs);
	xatp.size = nr_gfn;

	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);

	/* info->err_ptr expect to have one error status per Xen PFN */
	for (i = 0; i < nr_gfn; i++) {
		int err = (rc < 0) ? rc : info->h_errs[i];

		*(info->err_ptr++) = err;
		if (!err)
			info->mapped++;
	}

	/*
	 * Note: The hypercall will return 0 in most of the case if even if
	 * all the fgmfn are not mapped. We still have to update the pte
	 * as the userspace may decide to continue.
	 */
	if (!rc)
		set_pte_at(info->vma->vm_mm, addr, ptep, pte);

	return 0;
}

int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
			      unsigned long addr,
			      xen_pfn_t *gfn, int nr,
			      int *err_ptr, pgprot_t prot,
			      unsigned domid,
			      struct page **pages)
{
	int err;
	struct remap_data data;
	unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << PAGE_SHIFT;

Annotation

Implementation Notes