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Commit 5995a68a authored by Julien Grall's avatar Julien Grall Committed by David Vrabel
Browse files

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: default avatarJulien Grall <julien.grall@citrix.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent d0089e8a

drivers/xen/privcmd.c

+5 −3
Original line number Diff line number Diff line
@@ -446,7 +446,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version) 
		return -EINVAL;

	}



	nr_pages = m.num;

	nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);

	if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))

		return -EINVAL;
@@ -494,7 +494,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version) 
			goto out_unlock;

		}

		if (xen_feature(XENFEAT_auto_translated_physmap)) {

			ret = alloc_empty_pages(vma, m.num);

			ret = alloc_empty_pages(vma, nr_pages);

			if (ret < 0)

				goto out_unlock;

		} else
@@ -518,6 +518,7 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version) 
	state.global_error  = 0;

	state.version       = version;



	BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);

	/* mmap_batch_fn guarantees ret == 0 */

	BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),

				    &pagelist, mmap_batch_fn, &state));
@@ -582,12 +583,13 @@ 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 numgfns = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;

	int rc;



	if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)

		return;



	rc = xen_unmap_domain_gfn_range(vma, numpgs, pages);

	rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);

	if (rc == 0)

		free_xenballooned_pages(numpgs, pages);

	else

drivers/xen/xlate_mmu.c

+84 −40
Original line number Diff line number Diff line
@@ -38,31 +38,28 @@ 
#include <xen/interface/xen.h>

#include <xen/interface/memory.h>



/* map fgfn of domid to lpfn in the current domain */

static int map_foreign_page(unsigned long lpfn, unsigned long fgfn,

			    unsigned int domid)

{

	int rc;

	struct xen_add_to_physmap_range xatp = {

		.domid = DOMID_SELF,

		.foreign_domid = domid,

		.size = 1,

		.space = XENMAPSPACE_gmfn_foreign,

	};

	xen_ulong_t idx = fgfn;

	xen_pfn_t gpfn = lpfn;

	int err = 0;

typedef void (*xen_gfn_fn_t)(unsigned long gfn, void *data);



	set_xen_guest_handle(xatp.idxs, &idx);

	set_xen_guest_handle(xatp.gpfns, &gpfn);

	set_xen_guest_handle(xatp.errs, &err);

/* Break down the pages in 4KB chunk and call fn for each gfn */

static void xen_for_each_gfn(struct page **pages, unsigned nr_gfn,

			     xen_gfn_fn_t fn, void *data)

{

	unsigned long xen_pfn = 0;

	struct page *page;

	int i;



	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);

	return rc < 0 ? rc : err;

	for (i = 0; i < nr_gfn; i++) {

		if ((i % XEN_PFN_PER_PAGE) == 0) {

			page = pages[i / XEN_PFN_PER_PAGE];

			xen_pfn = page_to_xen_pfn(page);

		}

		fn(pfn_to_gfn(xen_pfn++), data);

	}

}



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;
@@ -71,24 +68,71 @@ struct remap_data { 
	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, pgtable_t token, unsigned long addr,

			void *data)

{

	struct remap_data *info = data;

	struct page *page = info->pages[info->index++];

	unsigned long pfn = page_to_pfn(page);

	pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));

	int rc;

	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,

	};



	rc = map_foreign_page(pfn, *info->fgfn, info->domid);

	*info->err_ptr++ = rc;

	if (!rc) {

		set_pte_at(info->vma->vm_mm, addr, ptep, pte);

	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++;

	}

	info->fgfn++;



	/*

	 * 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;

}
@@ -102,13 +146,14 @@ int xen_xlate_remap_gfn_array(struct vm_area_struct *vma, 
{

	int err;

	struct remap_data data;

	unsigned long range = nr << PAGE_SHIFT;

	unsigned long range = DIV_ROUND_UP(nr, XEN_PFN_PER_PAGE) << PAGE_SHIFT;



	/* Kept here for the purpose of making sure code doesn't break

	   x86 PVOPS */

	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));



	data.fgfn = gfn;

	data.nr_fgfn = nr;

	data.prot  = prot;

	data.domid = domid;

	data.vma   = vma;
@@ -123,21 +168,20 @@ int xen_xlate_remap_gfn_array(struct vm_area_struct *vma, 
}

EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);



int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,

			      int nr, struct page **pages)

static void unmap_gfn(unsigned long gfn, void *data)

{

	int i;



	for (i = 0; i < nr; i++) {

	struct xen_remove_from_physmap xrp;

		unsigned long pfn;



		pfn = page_to_pfn(pages[i]);



	xrp.domid = DOMID_SELF;

		xrp.gpfn = pfn;

	xrp.gpfn = gfn;

	(void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);

}



int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,

			      int nr, struct page **pages)

{

	xen_for_each_gfn(pages, nr, unmap_gfn, NULL);



	return 0;

}

EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);