// SPDX-License-Identifier: GPL-2.0
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/*
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* Xen leaves the responsibility for maintaining p2m mappings to the
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* guests themselves, but it must also access and update the p2m array
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* during suspend/resume when all the pages are reallocated.
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*
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* The logical flat p2m table is mapped to a linear kernel memory area.
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* For accesses by Xen a three-level tree linked via mfns only is set up to
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* allow the address space to be sparse.
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*
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* Xen
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* |
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* p2m_top_mfn
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* / \
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* p2m_mid_mfn p2m_mid_mfn
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* / /
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* p2m p2m p2m ...
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*
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* The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
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*
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* The p2m_top_mfn level is limited to 1 page, so the maximum representable
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* pseudo-physical address space is:
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* P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
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*
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* P2M_PER_PAGE depends on the architecture, as a mfn is always
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* unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
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* 512 and 1024 entries respectively.
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*
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* In short, these structures contain the Machine Frame Number (MFN) of the PFN.
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*
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* However not all entries are filled with MFNs. Specifically for all other
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* leaf entries, or for the top root, or middle one, for which there is a void
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* entry, we assume it is "missing". So (for example)
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* pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
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* We have a dedicated page p2m_missing with all entries being
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* INVALID_P2M_ENTRY. This page may be referenced multiple times in the p2m
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* list/tree in case there are multiple areas with P2M_PER_PAGE invalid pfns.
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*
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* We also have the possibility of setting 1-1 mappings on certain regions, so
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* that:
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* pfn_to_mfn(0xc0000)=0xc0000
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*
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* The benefit of this is, that we can assume for non-RAM regions (think
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* PCI BARs, or ACPI spaces), we can create mappings easily because we
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* get the PFN value to match the MFN.
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*
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* For this to work efficiently we have one new page p2m_identity. All entries
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* in p2m_identity are set to INVALID_P2M_ENTRY type (Xen toolstack only
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* recognizes that and MFNs, no other fancy value).
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*
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* On lookup we spot that the entry points to p2m_identity and return the
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* identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
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* If the entry points to an allocated page, we just proceed as before and
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* return the PFN. If the PFN has IDENTITY_FRAME_BIT set we unmask that in
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* appropriate functions (pfn_to_mfn).
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*
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* The reason for having the IDENTITY_FRAME_BIT instead of just returning the
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* PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
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* non-identity pfn. To protect ourselves against we elect to set (and get) the
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* IDENTITY_FRAME_BIT on all identity mapped PFNs.
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*/
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/list.h>
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#include <linux/hash.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/memblock.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <asm/cache.h>
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#include <asm/setup.h>
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#include <linux/uaccess.h>
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#include <asm/xen/page.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/balloon.h>
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#include <xen/grant_table.h>
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#include "multicalls.h"
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#include "xen-ops.h"
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#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
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#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
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#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
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#define PMDS_PER_MID_PAGE (P2M_MID_PER_PAGE / PTRS_PER_PTE)
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unsigned long *xen_p2m_addr __read_mostly;
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EXPORT_SYMBOL_GPL(xen_p2m_addr);
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unsigned long xen_p2m_size __read_mostly;
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EXPORT_SYMBOL_GPL(xen_p2m_size);
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unsigned long xen_max_p2m_pfn __read_mostly;
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EXPORT_SYMBOL_GPL(xen_max_p2m_pfn);
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#ifdef CONFIG_XEN_MEMORY_HOTPLUG_LIMIT
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#define P2M_LIMIT CONFIG_XEN_MEMORY_HOTPLUG_LIMIT
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#else
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#define P2M_LIMIT 0
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#endif
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static DEFINE_SPINLOCK(p2m_update_lock);
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static unsigned long *p2m_mid_missing_mfn;
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static unsigned long *p2m_top_mfn;
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static unsigned long **p2m_top_mfn_p;
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static unsigned long *p2m_missing;
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static unsigned long *p2m_identity;
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static pte_t *p2m_missing_pte;
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static pte_t *p2m_identity_pte;
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/*
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* Hint at last populated PFN.
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*
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* Used to set HYPERVISOR_shared_info->arch.max_pfn so the toolstack
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* can avoid scanning the whole P2M (which may be sized to account for
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* hotplugged memory).
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*/
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static unsigned long xen_p2m_last_pfn;
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static inline unsigned p2m_top_index(unsigned long pfn)
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{
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BUG_ON(pfn >= MAX_P2M_PFN);
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return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
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}
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static inline unsigned p2m_mid_index(unsigned long pfn)
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{
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return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
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}
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static inline unsigned p2m_index(unsigned long pfn)
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{
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return pfn % P2M_PER_PAGE;
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}
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static void p2m_top_mfn_init(unsigned long *top)
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{
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unsigned i;
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for (i = 0; i < P2M_TOP_PER_PAGE; i++)
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top[i] = virt_to_mfn(p2m_mid_missing_mfn);
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}
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static void p2m_top_mfn_p_init(unsigned long **top)
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{
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unsigned i;
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for (i = 0; i < P2M_TOP_PER_PAGE; i++)
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top[i] = p2m_mid_missing_mfn;
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}
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static void p2m_mid_mfn_init(unsigned long *mid, unsigned long *leaf)
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{
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unsigned i;
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for (i = 0; i < P2M_MID_PER_PAGE; i++)
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mid[i] = virt_to_mfn(leaf);
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}
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static void p2m_init(unsigned long *p2m)
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{
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unsigned i;
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for (i = 0; i < P2M_PER_PAGE; i++)
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p2m[i] = INVALID_P2M_ENTRY;
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}
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static void p2m_init_identity(unsigned long *p2m, unsigned long pfn)
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{
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unsigned i;
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for (i = 0; i < P2M_PER_PAGE; i++)
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p2m[i] = IDENTITY_FRAME(pfn + i);
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}
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static void * __ref alloc_p2m_page(void)
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{
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if (unlikely(!slab_is_available())) {
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void *ptr = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
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if (!ptr)
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panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
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__func__, PAGE_SIZE, PAGE_SIZE);
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return ptr;
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}
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return (void *)__get_free_page(GFP_KERNEL);
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}
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static void __ref free_p2m_page(void *p)
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{
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if (unlikely(!slab_is_available())) {
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memblock_free((unsigned long)p, PAGE_SIZE);
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return;
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}
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free_page((unsigned long)p);
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}
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/*
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* Build the parallel p2m_top_mfn and p2m_mid_mfn structures
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*
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* This is called both at boot time, and after resuming from suspend:
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* - At boot time we're called rather early, and must use alloc_bootmem*()
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* to allocate memory.
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*
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* - After resume we're called from within stop_machine, but the mfn
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* tree should already be completely allocated.
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*/
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void __ref xen_build_mfn_list_list(void)
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{
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unsigned long pfn, mfn;
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pte_t *ptep;
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unsigned int level, topidx, mididx;
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unsigned long *mid_mfn_p;
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if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
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return;
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/* Pre-initialize p2m_top_mfn to be completely missing */
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if (p2m_top_mfn == NULL) {
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p2m_mid_missing_mfn = alloc_p2m_page();
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p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
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p2m_top_mfn_p = alloc_p2m_page();
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p2m_top_mfn_p_init(p2m_top_mfn_p);
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p2m_top_mfn = alloc_p2m_page();
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p2m_top_mfn_init(p2m_top_mfn);
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} else {
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/* Reinitialise, mfn's all change after migration */
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p2m_mid_mfn_init(p2m_mid_missing_mfn, p2m_missing);
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}
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for (pfn = 0; pfn < xen_max_p2m_pfn && pfn < MAX_P2M_PFN;
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pfn += P2M_PER_PAGE) {
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topidx = p2m_top_index(pfn);
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mididx = p2m_mid_index(pfn);
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mid_mfn_p = p2m_top_mfn_p[topidx];
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ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn),
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&level);
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BUG_ON(!ptep || level != PG_LEVEL_4K);
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mfn = pte_mfn(*ptep);
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ptep = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
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/* Don't bother allocating any mfn mid levels if
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* they're just missing, just update the stored mfn,
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* since all could have changed over a migrate.
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*/
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if (ptep == p2m_missing_pte || ptep == p2m_identity_pte) {
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BUG_ON(mididx);
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BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
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p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
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pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
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continue;
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}
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if (mid_mfn_p == p2m_mid_missing_mfn) {
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mid_mfn_p = alloc_p2m_page();
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p2m_mid_mfn_init(mid_mfn_p, p2m_missing);
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p2m_top_mfn_p[topidx] = mid_mfn_p;
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}
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p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
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mid_mfn_p[mididx] = mfn;
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}
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}
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void xen_setup_mfn_list_list(void)
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{
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BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
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if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
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HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;
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else
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HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
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virt_to_mfn(p2m_top_mfn);
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HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
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HYPERVISOR_shared_info->arch.p2m_generation = 0;
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HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;
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HYPERVISOR_shared_info->arch.p2m_cr3 =
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xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
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}
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/* Set up p2m_top to point to the domain-builder provided p2m pages */
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void __init xen_build_dynamic_phys_to_machine(void)
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{
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unsigned long pfn;
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xen_p2m_addr = (unsigned long *)xen_start_info->mfn_list;
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xen_p2m_size = ALIGN(xen_start_info->nr_pages, P2M_PER_PAGE);
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for (pfn = xen_start_info->nr_pages; pfn < xen_p2m_size; pfn++)
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xen_p2m_addr[pfn] = INVALID_P2M_ENTRY;
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xen_max_p2m_pfn = xen_p2m_size;
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}
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#define P2M_TYPE_IDENTITY 0
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#define P2M_TYPE_MISSING 1
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#define P2M_TYPE_PFN 2
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#define P2M_TYPE_UNKNOWN 3
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static int xen_p2m_elem_type(unsigned long pfn)
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{
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unsigned long mfn;
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if (pfn >= xen_p2m_size)
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return P2M_TYPE_IDENTITY;
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mfn = xen_p2m_addr[pfn];
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if (mfn == INVALID_P2M_ENTRY)
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return P2M_TYPE_MISSING;
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if (mfn & IDENTITY_FRAME_BIT)
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return P2M_TYPE_IDENTITY;
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return P2M_TYPE_PFN;
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}
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static void __init xen_rebuild_p2m_list(unsigned long *p2m)
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{
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unsigned int i, chunk;
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unsigned long pfn;
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unsigned long *mfns;
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pte_t *ptep;
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pmd_t *pmdp;
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int type;
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p2m_missing = alloc_p2m_page();
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p2m_init(p2m_missing);
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p2m_identity = alloc_p2m_page();
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p2m_init(p2m_identity);
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p2m_missing_pte = alloc_p2m_page();
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paravirt_alloc_pte(&init_mm, __pa(p2m_missing_pte) >> PAGE_SHIFT);
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p2m_identity_pte = alloc_p2m_page();
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paravirt_alloc_pte(&init_mm, __pa(p2m_identity_pte) >> PAGE_SHIFT);
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for (i = 0; i < PTRS_PER_PTE; i++) {
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set_pte(p2m_missing_pte + i,
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pfn_pte(PFN_DOWN(__pa(p2m_missing)), PAGE_KERNEL_RO));
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set_pte(p2m_identity_pte + i,
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pfn_pte(PFN_DOWN(__pa(p2m_identity)), PAGE_KERNEL_RO));
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}
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for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += chunk) {
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/*
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* Try to map missing/identity PMDs or p2m-pages if possible.
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* We have to respect the structure of the mfn_list_list
|
* which will be built just afterwards.
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* Chunk size to test is one p2m page if we are in the middle
|
* of a mfn_list_list mid page and the complete mid page area
|
* if we are at index 0 of the mid page. Please note that a
|
* mid page might cover more than one PMD, e.g. on 32 bit PAE
|
* kernels.
|
*/
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chunk = (pfn & (P2M_PER_PAGE * P2M_MID_PER_PAGE - 1)) ?
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P2M_PER_PAGE : P2M_PER_PAGE * P2M_MID_PER_PAGE;
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type = xen_p2m_elem_type(pfn);
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i = 0;
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if (type != P2M_TYPE_PFN)
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for (i = 1; i < chunk; i++)
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if (xen_p2m_elem_type(pfn + i) != type)
|
break;
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if (i < chunk)
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/* Reset to minimal chunk size. */
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chunk = P2M_PER_PAGE;
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if (type == P2M_TYPE_PFN || i < chunk) {
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/* Use initial p2m page contents. */
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mfns = alloc_p2m_page();
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copy_page(mfns, xen_p2m_addr + pfn);
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ptep = populate_extra_pte((unsigned long)(p2m + pfn));
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set_pte(ptep,
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pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL));
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continue;
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}
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if (chunk == P2M_PER_PAGE) {
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/* Map complete missing or identity p2m-page. */
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mfns = (type == P2M_TYPE_MISSING) ?
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p2m_missing : p2m_identity;
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ptep = populate_extra_pte((unsigned long)(p2m + pfn));
|
set_pte(ptep,
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pfn_pte(PFN_DOWN(__pa(mfns)), PAGE_KERNEL_RO));
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continue;
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}
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/* Complete missing or identity PMD(s) can be mapped. */
|
ptep = (type == P2M_TYPE_MISSING) ?
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p2m_missing_pte : p2m_identity_pte;
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for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
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pmdp = populate_extra_pmd(
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(unsigned long)(p2m + pfn) + i * PMD_SIZE);
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set_pmd(pmdp, __pmd(__pa(ptep) | _KERNPG_TABLE));
|
}
|
}
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}
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void __init xen_vmalloc_p2m_tree(void)
|
{
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static struct vm_struct vm;
|
unsigned long p2m_limit;
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|
xen_p2m_last_pfn = xen_max_p2m_pfn;
|
|
p2m_limit = (phys_addr_t)P2M_LIMIT * 1024 * 1024 * 1024 / PAGE_SIZE;
|
vm.flags = VM_ALLOC;
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vm.size = ALIGN(sizeof(unsigned long) * max(xen_max_p2m_pfn, p2m_limit),
|
PMD_SIZE * PMDS_PER_MID_PAGE);
|
vm_area_register_early(&vm, PMD_SIZE * PMDS_PER_MID_PAGE);
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pr_notice("p2m virtual area at %p, size is %lx\n", vm.addr, vm.size);
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xen_max_p2m_pfn = vm.size / sizeof(unsigned long);
|
|
xen_rebuild_p2m_list(vm.addr);
|
|
xen_p2m_addr = vm.addr;
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xen_p2m_size = xen_max_p2m_pfn;
|
|
xen_inv_extra_mem();
|
}
|
|
unsigned long get_phys_to_machine(unsigned long pfn)
|
{
|
pte_t *ptep;
|
unsigned int level;
|
|
if (unlikely(pfn >= xen_p2m_size)) {
|
if (pfn < xen_max_p2m_pfn)
|
return xen_chk_extra_mem(pfn);
|
|
return IDENTITY_FRAME(pfn);
|
}
|
|
ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
|
BUG_ON(!ptep || level != PG_LEVEL_4K);
|
|
/*
|
* The INVALID_P2M_ENTRY is filled in both p2m_*identity
|
* and in p2m_*missing, so returning the INVALID_P2M_ENTRY
|
* would be wrong.
|
*/
|
if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
|
return IDENTITY_FRAME(pfn);
|
|
return xen_p2m_addr[pfn];
|
}
|
EXPORT_SYMBOL_GPL(get_phys_to_machine);
|
|
/*
|
* Allocate new pmd(s). It is checked whether the old pmd is still in place.
|
* If not, nothing is changed. This is okay as the only reason for allocating
|
* a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual
|
* pmd.
|
*/
|
static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
|
{
|
pte_t *ptechk;
|
pte_t *pte_newpg[PMDS_PER_MID_PAGE];
|
pmd_t *pmdp;
|
unsigned int level;
|
unsigned long flags;
|
unsigned long vaddr;
|
int i;
|
|
/* Do all allocations first to bail out in error case. */
|
for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
|
pte_newpg[i] = alloc_p2m_page();
|
if (!pte_newpg[i]) {
|
for (i--; i >= 0; i--)
|
free_p2m_page(pte_newpg[i]);
|
|
return NULL;
|
}
|
}
|
|
vaddr = addr & ~(PMD_SIZE * PMDS_PER_MID_PAGE - 1);
|
|
for (i = 0; i < PMDS_PER_MID_PAGE; i++) {
|
copy_page(pte_newpg[i], pte_pg);
|
paravirt_alloc_pte(&init_mm, __pa(pte_newpg[i]) >> PAGE_SHIFT);
|
|
pmdp = lookup_pmd_address(vaddr);
|
BUG_ON(!pmdp);
|
|
spin_lock_irqsave(&p2m_update_lock, flags);
|
|
ptechk = lookup_address(vaddr, &level);
|
if (ptechk == pte_pg) {
|
HYPERVISOR_shared_info->arch.p2m_generation++;
|
wmb(); /* Tools are synchronizing via p2m_generation. */
|
set_pmd(pmdp,
|
__pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
|
wmb(); /* Tools are synchronizing via p2m_generation. */
|
HYPERVISOR_shared_info->arch.p2m_generation++;
|
pte_newpg[i] = NULL;
|
}
|
|
spin_unlock_irqrestore(&p2m_update_lock, flags);
|
|
if (pte_newpg[i]) {
|
paravirt_release_pte(__pa(pte_newpg[i]) >> PAGE_SHIFT);
|
free_p2m_page(pte_newpg[i]);
|
}
|
|
vaddr += PMD_SIZE;
|
}
|
|
return lookup_address(addr, &level);
|
}
|
|
/*
|
* Fully allocate the p2m structure for a given pfn. We need to check
|
* that both the top and mid levels are allocated, and make sure the
|
* parallel mfn tree is kept in sync. We may race with other cpus, so
|
* the new pages are installed with cmpxchg; if we lose the race then
|
* simply free the page we allocated and use the one that's there.
|
*/
|
int xen_alloc_p2m_entry(unsigned long pfn)
|
{
|
unsigned topidx;
|
unsigned long *top_mfn_p, *mid_mfn;
|
pte_t *ptep, *pte_pg;
|
unsigned int level;
|
unsigned long flags;
|
unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
|
unsigned long p2m_pfn;
|
|
ptep = lookup_address(addr, &level);
|
BUG_ON(!ptep || level != PG_LEVEL_4K);
|
pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
|
|
if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) {
|
/* PMD level is missing, allocate a new one */
|
ptep = alloc_p2m_pmd(addr, pte_pg);
|
if (!ptep)
|
return -ENOMEM;
|
}
|
|
if (p2m_top_mfn && pfn < MAX_P2M_PFN) {
|
topidx = p2m_top_index(pfn);
|
top_mfn_p = &p2m_top_mfn[topidx];
|
mid_mfn = READ_ONCE(p2m_top_mfn_p[topidx]);
|
|
BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
|
|
if (mid_mfn == p2m_mid_missing_mfn) {
|
/* Separately check the mid mfn level */
|
unsigned long missing_mfn;
|
unsigned long mid_mfn_mfn;
|
unsigned long old_mfn;
|
|
mid_mfn = alloc_p2m_page();
|
if (!mid_mfn)
|
return -ENOMEM;
|
|
p2m_mid_mfn_init(mid_mfn, p2m_missing);
|
|
missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
|
mid_mfn_mfn = virt_to_mfn(mid_mfn);
|
old_mfn = cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn);
|
if (old_mfn != missing_mfn) {
|
free_p2m_page(mid_mfn);
|
mid_mfn = mfn_to_virt(old_mfn);
|
} else {
|
p2m_top_mfn_p[topidx] = mid_mfn;
|
}
|
}
|
} else {
|
mid_mfn = NULL;
|
}
|
|
p2m_pfn = pte_pfn(READ_ONCE(*ptep));
|
if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) ||
|
p2m_pfn == PFN_DOWN(__pa(p2m_missing))) {
|
/* p2m leaf page is missing */
|
unsigned long *p2m;
|
|
p2m = alloc_p2m_page();
|
if (!p2m)
|
return -ENOMEM;
|
|
if (p2m_pfn == PFN_DOWN(__pa(p2m_missing)))
|
p2m_init(p2m);
|
else
|
p2m_init_identity(p2m, pfn & ~(P2M_PER_PAGE - 1));
|
|
spin_lock_irqsave(&p2m_update_lock, flags);
|
|
if (pte_pfn(*ptep) == p2m_pfn) {
|
HYPERVISOR_shared_info->arch.p2m_generation++;
|
wmb(); /* Tools are synchronizing via p2m_generation. */
|
set_pte(ptep,
|
pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
|
wmb(); /* Tools are synchronizing via p2m_generation. */
|
HYPERVISOR_shared_info->arch.p2m_generation++;
|
if (mid_mfn)
|
mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m);
|
p2m = NULL;
|
}
|
|
spin_unlock_irqrestore(&p2m_update_lock, flags);
|
|
if (p2m)
|
free_p2m_page(p2m);
|
}
|
|
/* Expanded the p2m? */
|
if (pfn >= xen_p2m_last_pfn) {
|
xen_p2m_last_pfn = ALIGN(pfn + 1, P2M_PER_PAGE);
|
HYPERVISOR_shared_info->arch.max_pfn = xen_p2m_last_pfn;
|
}
|
|
return 0;
|
}
|
EXPORT_SYMBOL(xen_alloc_p2m_entry);
|
|
unsigned long __init set_phys_range_identity(unsigned long pfn_s,
|
unsigned long pfn_e)
|
{
|
unsigned long pfn;
|
|
if (unlikely(pfn_s >= xen_p2m_size))
|
return 0;
|
|
if (pfn_s > pfn_e)
|
return 0;
|
|
if (pfn_e > xen_p2m_size)
|
pfn_e = xen_p2m_size;
|
|
for (pfn = pfn_s; pfn < pfn_e; pfn++)
|
xen_p2m_addr[pfn] = IDENTITY_FRAME(pfn);
|
|
return pfn - pfn_s;
|
}
|
|
bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
{
|
pte_t *ptep;
|
unsigned int level;
|
|
/* Only invalid entries allowed above the highest p2m covered frame. */
|
if (unlikely(pfn >= xen_p2m_size))
|
return mfn == INVALID_P2M_ENTRY;
|
|
/*
|
* The interface requires atomic updates on p2m elements.
|
* xen_safe_write_ulong() is using an atomic store via asm().
|
*/
|
if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
|
return true;
|
|
ptep = lookup_address((unsigned long)(xen_p2m_addr + pfn), &level);
|
BUG_ON(!ptep || level != PG_LEVEL_4K);
|
|
if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_missing)))
|
return mfn == INVALID_P2M_ENTRY;
|
|
if (pte_pfn(*ptep) == PFN_DOWN(__pa(p2m_identity)))
|
return mfn == IDENTITY_FRAME(pfn);
|
|
return false;
|
}
|
|
bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
|
{
|
if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
|
int ret;
|
|
ret = xen_alloc_p2m_entry(pfn);
|
if (ret < 0)
|
return false;
|
|
return __set_phys_to_machine(pfn, mfn);
|
}
|
|
return true;
|
}
|
|
int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
|
struct gnttab_map_grant_ref *kmap_ops,
|
struct page **pages, unsigned int count)
|
{
|
int i, ret = 0;
|
pte_t *pte;
|
|
if (xen_feature(XENFEAT_auto_translated_physmap))
|
return 0;
|
|
if (kmap_ops) {
|
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
|
kmap_ops, count);
|
if (ret)
|
goto out;
|
}
|
|
for (i = 0; i < count; i++) {
|
unsigned long mfn, pfn;
|
struct gnttab_unmap_grant_ref unmap[2];
|
int rc;
|
|
/* Do not add to override if the map failed. */
|
if (map_ops[i].status != GNTST_okay ||
|
(kmap_ops && kmap_ops[i].status != GNTST_okay))
|
continue;
|
|
if (map_ops[i].flags & GNTMAP_contains_pte) {
|
pte = (pte_t *)(mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
|
(map_ops[i].host_addr & ~PAGE_MASK));
|
mfn = pte_mfn(*pte);
|
} else {
|
mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
|
}
|
pfn = page_to_pfn(pages[i]);
|
|
WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");
|
|
if (likely(set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
|
continue;
|
|
/*
|
* Signal an error for this slot. This in turn requires
|
* immediate unmapping.
|
*/
|
map_ops[i].status = GNTST_general_error;
|
unmap[0].host_addr = map_ops[i].host_addr,
|
unmap[0].handle = map_ops[i].handle;
|
map_ops[i].handle = ~0;
|
if (map_ops[i].flags & GNTMAP_device_map)
|
unmap[0].dev_bus_addr = map_ops[i].dev_bus_addr;
|
else
|
unmap[0].dev_bus_addr = 0;
|
|
if (kmap_ops) {
|
kmap_ops[i].status = GNTST_general_error;
|
unmap[1].host_addr = kmap_ops[i].host_addr,
|
unmap[1].handle = kmap_ops[i].handle;
|
kmap_ops[i].handle = ~0;
|
if (kmap_ops[i].flags & GNTMAP_device_map)
|
unmap[1].dev_bus_addr = kmap_ops[i].dev_bus_addr;
|
else
|
unmap[1].dev_bus_addr = 0;
|
}
|
|
/*
|
* Pre-populate both status fields, to be recognizable in
|
* the log message below.
|
*/
|
unmap[0].status = 1;
|
unmap[1].status = 1;
|
|
rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
|
unmap, 1 + !!kmap_ops);
|
if (rc || unmap[0].status != GNTST_okay ||
|
unmap[1].status != GNTST_okay)
|
pr_err_once("gnttab unmap failed: rc=%d st0=%d st1=%d\n",
|
rc, unmap[0].status, unmap[1].status);
|
}
|
|
out:
|
return ret;
|
}
|
EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
|
|
int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
|
struct gnttab_unmap_grant_ref *kunmap_ops,
|
struct page **pages, unsigned int count)
|
{
|
int i, ret = 0;
|
|
if (xen_feature(XENFEAT_auto_translated_physmap))
|
return 0;
|
|
for (i = 0; i < count; i++) {
|
unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
|
unsigned long pfn = page_to_pfn(pages[i]);
|
|
if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT))
|
set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
|
else
|
ret = -EINVAL;
|
}
|
if (kunmap_ops)
|
ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
|
kunmap_ops, count) ?: ret;
|
|
return ret;
|
}
|
EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
|
|
#ifdef CONFIG_XEN_DEBUG_FS
|
#include <linux/debugfs.h>
|
#include "debugfs.h"
|
static int p2m_dump_show(struct seq_file *m, void *v)
|
{
|
static const char * const type_name[] = {
|
[P2M_TYPE_IDENTITY] = "identity",
|
[P2M_TYPE_MISSING] = "missing",
|
[P2M_TYPE_PFN] = "pfn",
|
[P2M_TYPE_UNKNOWN] = "abnormal"};
|
unsigned long pfn, first_pfn;
|
int type, prev_type;
|
|
prev_type = xen_p2m_elem_type(0);
|
first_pfn = 0;
|
|
for (pfn = 0; pfn < xen_p2m_size; pfn++) {
|
type = xen_p2m_elem_type(pfn);
|
if (type != prev_type) {
|
seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
|
type_name[prev_type]);
|
prev_type = type;
|
first_pfn = pfn;
|
}
|
}
|
seq_printf(m, " [0x%lx->0x%lx] %s\n", first_pfn, pfn,
|
type_name[prev_type]);
|
return 0;
|
}
|
|
static int p2m_dump_open(struct inode *inode, struct file *filp)
|
{
|
return single_open(filp, p2m_dump_show, NULL);
|
}
|
|
static const struct file_operations p2m_dump_fops = {
|
.open = p2m_dump_open,
|
.read = seq_read,
|
.llseek = seq_lseek,
|
.release = single_release,
|
};
|
|
static struct dentry *d_mmu_debug;
|
|
static int __init xen_p2m_debugfs(void)
|
{
|
struct dentry *d_xen = xen_init_debugfs();
|
|
d_mmu_debug = debugfs_create_dir("mmu", d_xen);
|
|
debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
|
return 0;
|
}
|
fs_initcall(xen_p2m_debugfs);
|
#endif /* CONFIG_XEN_DEBUG_FS */
|
