Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 77945ca7 authored by Mukesh Rathor's avatar Mukesh Rathor Committed by David Vrabel
Browse files

x86/xen: map foreign pfns for autotranslated guests 



When running as a dom0 in PVH mode, foreign pfns that are accessed
must be added to our p2m which is managed by xen. This is done via
XENMEM_add_to_physmap_range hypercall. This is needed for toolstack
building guests and mapping guest memory, xentrace mapping xen pages,
etc.

Signed-off-by: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 1a4b50f6

arch/x86/xen/mmu.c

+118 −3
Original line number Diff line number Diff line
@@ -2510,6 +2510,95 @@ void __init xen_hvm_init_mmu_ops(void) 
}

#endif



#ifdef CONFIG_XEN_PVH

/*

 * Map foreign gfn (fgfn), to local pfn (lpfn). This for the user

 * space creating new guest on pvh dom0 and needing to map domU pages.

 */

static int xlate_add_to_p2m(unsigned long lpfn, unsigned long fgfn,

			    unsigned int domid)

{

	int rc, err = 0;

	xen_pfn_t gpfn = lpfn;

	xen_ulong_t idx = fgfn;



	struct xen_add_to_physmap_range xatp = {

		.domid = DOMID_SELF,

		.foreign_domid = domid,

		.size = 1,

		.space = XENMAPSPACE_gmfn_foreign,

	};

	set_xen_guest_handle(xatp.idxs, &idx);

	set_xen_guest_handle(xatp.gpfns, &gpfn);

	set_xen_guest_handle(xatp.errs, &err);



	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);

	if (rc < 0)

		return rc;

	return err;

}



static int xlate_remove_from_p2m(unsigned long spfn, int count)

{

	struct xen_remove_from_physmap xrp;

	int i, rc;



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

		xrp.domid = DOMID_SELF;

		xrp.gpfn = spfn+i;

		rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);

		if (rc)

			break;

	}

	return rc;

}



struct xlate_remap_data {

	unsigned long fgfn; /* foreign domain's gfn */

	pgprot_t prot;

	domid_t  domid;

	int index;

	struct page **pages;

};



static int xlate_map_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,

			    void *data)

{

	int rc;

	struct xlate_remap_data *remap = data;

	unsigned long pfn = page_to_pfn(remap->pages[remap->index++]);

	pte_t pteval = pte_mkspecial(pfn_pte(pfn, remap->prot));



	rc = xlate_add_to_p2m(pfn, remap->fgfn, remap->domid);

	if (rc)

		return rc;

	native_set_pte(ptep, pteval);



	return 0;

}



static int xlate_remap_gfn_range(struct vm_area_struct *vma,

				 unsigned long addr, unsigned long mfn,

				 int nr, pgprot_t prot, unsigned domid,

				 struct page **pages)

{

	int err;

	struct xlate_remap_data pvhdata;



	BUG_ON(!pages);



	pvhdata.fgfn = mfn;

	pvhdata.prot = prot;

	pvhdata.domid = domid;

	pvhdata.index = 0;

	pvhdata.pages = pages;

	err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,

				  xlate_map_pte_fn, &pvhdata);

	flush_tlb_all();

	return err;

}

#endif



#define REMAP_BATCH_SIZE 16



struct remap_data {
@@ -2544,11 +2633,18 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma, 
	unsigned long range;

	int err = 0;



	if (xen_feature(XENFEAT_auto_translated_physmap))

		return -EINVAL;



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



	if (xen_feature(XENFEAT_auto_translated_physmap)) {

#ifdef CONFIG_XEN_PVH

		/* We need to update the local page tables and the xen HAP */

		return xlate_remap_gfn_range(vma, addr, mfn, nr, prot,

					     domid, pages);

#else

		return -EINVAL;

#endif

        }



	rmd.mfn = mfn;

	rmd.prot = prot;
@@ -2586,6 +2682,25 @@ int xen_unmap_domain_mfn_range(struct vm_area_struct *vma, 
	if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))

		return 0;



#ifdef CONFIG_XEN_PVH

	while (numpgs--) {

		/*

		 * The mmu has already cleaned up the process mmu

		 * resources at this point (lookup_address will return

		 * NULL).

		 */

		unsigned long pfn = page_to_pfn(pages[numpgs]);



		xlate_remove_from_p2m(pfn, 1);

	}

	/*

	 * We don't need to flush tlbs because as part of

	 * xlate_remove_from_p2m, the hypervisor will do tlb flushes

	 * after removing the p2m entries from the EPT/NPT

	 */

	return 0;

#else

	return -EINVAL;

#endif

}

EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);