1 // SPDX-License-Identifier: GPL-2.0
4  * Xen leaves the responsibility for maintaining p2m mappings to the
8  * The logical flat p2m table is mapped to a linear kernel memory area.
9  * For accesses by Xen a three-level tree linked via mfns only is set up to
10  * allow the address space to be sparse.
22  * The p2m_top_mfn level is limited to 1 page, so the maximum representable
23  * pseudo-physical address space is:
27  * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
40  * We also have the possibility of setting 1-1 mappings on certain regions, so
44  * The benefit of this is, that we can assume for non-RAM regions (think
46  * get the PFN value to match the MFN.
48  * For this to work efficiently we have one new page p2m_identity. All entries
49  * in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only
52  * On lookup we spot that the entry points to p2m_identity and return the
54  * If the entry points to an allocated page, we just proceed as before and
60  * non-identity pfn. To protect ourselves against we elect to set (and get) the
84 #include <xen/hvc-console.h>
86 #include "xen-ops.h"
121  * Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack
122  * can avoid scanning the whole P2M (which may be sized to account for
154 static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)  in p2m_mid_mfn_init()  argument
159 		mid[i] = virt_to_mfn(leaf);  in p2m_mid_mfn_init()
201  * - At boot time we're called rather early, and must use alloc_bootmem*()
202  *   to allocate memory.
204  * - After resume we're called from within stop_machine, but the mfn
214 	if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)  in xen_build_mfn_list_list()
217 	/* Pre-initialize p2m_top_mfn to be completely missing */  in xen_build_mfn_list_list()
242 		ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));  in xen_build_mfn_list_list()
244 		/* Don't bother allocating any mfn mid levels if  in xen_build_mfn_list_list()
252 			pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;  in xen_build_mfn_list_list()
272 	if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)  in xen_setup_mfn_list_list()
273 		HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;  in xen_setup_mfn_list_list()
275 		HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =  in xen_setup_mfn_list_list()
277 	HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;  in xen_setup_mfn_list_list()
278 	HYPERVISOR_shared_info->arch.p2m_generation = 0;  in xen_setup_mfn_list_list()
279 	HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;  in xen_setup_mfn_list_list()
280 	HYPERVISOR_shared_info->arch.p2m_cr3 =  in xen_setup_mfn_list_list()
284 /* Set up p2m_top to point to the domain-builder provided p2m pages */
289 	xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;  in xen_build_dynamic_phys_to_machine()
290 	xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);  in xen_build_dynamic_phys_to_machine()
292 	for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)  in xen_build_dynamic_phys_to_machine()
348 		 * Try to map missing/identity PMDs or p2m-pages if possible.  in xen_rebuild_p2m_list()
349 		 * We have to respect the structure of the mfn_list_list  in xen_rebuild_p2m_list()
351 		 * Chunk size to test is one p2m page if we are in the middle  in xen_rebuild_p2m_list()
352 		 * of a mfn_list_list mid page and the complete mid page area  in xen_rebuild_p2m_list()
353 		 * if we are at index 0 of the mid page. Please note that a  in xen_rebuild_p2m_list()
354 		 * mid page might cover more than one PMD, e.g. on 32 bit PAE  in xen_rebuild_p2m_list()
357 		chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?  in xen_rebuild_p2m_list()
367 			/* Reset to minimal chunk size. */  in xen_rebuild_p2m_list()
381 			/* Map complete missing or identity p2m-page. */  in xen_rebuild_p2m_list()
455  * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
468 	/* Do all allocations first to bail out in error case. */  in alloc_p2m_pmd()
472 			for (i--; i >= 0; i--)  in alloc_p2m_pmd()
479 	vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);  in alloc_p2m_pmd()
492 			HYPERVISOR_shared_info->arch.p2m_generation++;  in alloc_p2m_pmd()
497 			HYPERVISOR_shared_info->arch.p2m_generation++;  in alloc_p2m_pmd()
515  * Fully allocate the p2m structure for a given pfn.  We need to check
516  * that both the top and mid levels are allocated, and make sure the
533 	pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));  in xen_alloc_p2m_entry()
539 			return -ENOMEM;  in xen_alloc_p2m_entry()
550 			/* Separately check the mid mfn level */  in xen_alloc_p2m_entry()
556 				return -ENOMEM;  in xen_alloc_p2m_entry()
582 			return -ENOMEM;  in xen_alloc_p2m_entry()
587 			p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));  in xen_alloc_p2m_entry()
592 			HYPERVISOR_shared_info->arch.p2m_generation++;  in xen_alloc_p2m_entry()
597 			HYPERVISOR_shared_info->arch.p2m_generation++;  in xen_alloc_p2m_entry()
612 		HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;  in xen_alloc_p2m_entry()
636 	return pfn - pfn_s;  in set_phys_range_identity()
704 		/* Do not add to override if the map failed. */  in set_foreign_p2m_mapping()
748 		 * Pre-populate both status fields, to be recognizable in  in set_foreign_p2m_mapping()
782 			ret = -EINVAL;  in clear_foreign_p2m_mapping()
791 /* Remapped non-RAM areas */
801  * Do the real remapping of non-RAM regions as specified in the
813 		end_pfn = PFN_UP(remap->paddr + remap->size);  in xen_do_remap_nonram()
814 		pfn = PFN_DOWN(remap->paddr);  in xen_do_remap_nonram()
815 		mfn = PFN_DOWN(remap->maddr);  in xen_do_remap_nonram()
818 				panic("Failed to set p2m mapping for pfn=%lx mfn=%lx\n",  in xen_do_remap_nonram()
829 	pr_info("Remapped %u non-RAM page(s)\n", remapped);  in xen_do_remap_nonram()
834  * Xen variant of acpi_os_ioremap() taking potentially remapped non-RAM
836  * Any attempt to map an area crossing a remap boundary will produce a
838  * phys is related to remap->maddr on input and will be rebased to remap->paddr.
847 		if (phys + size > remap->maddr &&  in xen_acpi_os_ioremap()
848 		    phys < remap->maddr + remap->size) {  in xen_acpi_os_ioremap()
849 			WARN_ON(phys < remap->maddr ||  in xen_acpi_os_ioremap()
850 				phys + size > remap->maddr + remap->size);  in xen_acpi_os_ioremap()
851 			phys += remap->paddr - remap->maddr;  in xen_acpi_os_ioremap()
861  * Add a new non-RAM remap entry.
875 	/* Switch to the Xen acpi_os_ioremap() variant. */  in xen_add_remap_nonram()
905 			seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,  in p2m_dump_show()
911 	seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,  in p2m_dump_show()