diff options
Diffstat (limited to 'arch/x86/xen/grant-table.c')
| -rw-r--r-- | arch/x86/xen/grant-table.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c new file mode 100644 index 0000000000..1e681bf625 --- /dev/null +++ b/arch/x86/xen/grant-table.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/****************************************************************************** + * grant_table.c + * x86 specific part + * + * Granting foreign access to our memory reservation. + * + * Copyright (c) 2005-2006, Christopher Clark + * Copyright (c) 2004-2005, K A Fraser + * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp> + * VA Linux Systems Japan. Split out x86 specific part. + */ + +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +#include <xen/interface/xen.h> +#include <xen/page.h> +#include <xen/grant_table.h> +#include <xen/xen.h> + + +static struct gnttab_vm_area { + struct vm_struct *area; + pte_t **ptes; + int idx; +} gnttab_shared_vm_area, gnttab_status_vm_area; + +int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes, + unsigned long max_nr_gframes, + void **__shared) +{ + void *shared = *__shared; + unsigned long addr; + unsigned long i; + + if (shared == NULL) + *__shared = shared = gnttab_shared_vm_area.area->addr; + + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i], + mfn_pte(frames[i], PAGE_KERNEL)); + addr += PAGE_SIZE; + } + + return 0; +} + +int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes, + unsigned long max_nr_gframes, + grant_status_t **__shared) +{ + grant_status_t *shared = *__shared; + unsigned long addr; + unsigned long i; + + if (shared == NULL) + *__shared = shared = gnttab_status_vm_area.area->addr; + + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i], + mfn_pte(frames[i], PAGE_KERNEL)); + addr += PAGE_SIZE; + } + + return 0; +} + +void arch_gnttab_unmap(void *shared, unsigned long nr_gframes) +{ + pte_t **ptes; + unsigned long addr; + unsigned long i; + + if (shared == gnttab_status_vm_area.area->addr) + ptes = gnttab_status_vm_area.ptes; + else + ptes = gnttab_shared_vm_area.ptes; + + addr = (unsigned long)shared; + + for (i = 0; i < nr_gframes; i++) { + set_pte_at(&init_mm, addr, ptes[i], __pte(0)); + addr += PAGE_SIZE; + } +} + +static int gnttab_apply(pte_t *pte, unsigned long addr, void *data) +{ + struct gnttab_vm_area *area = data; + + area->ptes[area->idx++] = pte; + return 0; +} + +static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames) +{ + area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL); + if (area->ptes == NULL) + return -ENOMEM; + area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP); + if (!area->area) + goto out_free_ptes; + if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr, + PAGE_SIZE * nr_frames, gnttab_apply, area)) + goto out_free_vm_area; + return 0; +out_free_vm_area: + free_vm_area(area->area); +out_free_ptes: + kfree(area->ptes); + return -ENOMEM; +} + +static void arch_gnttab_vfree(struct gnttab_vm_area *area) +{ + free_vm_area(area->area); + kfree(area->ptes); +} + +int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status) +{ + int ret; + + if (!xen_pv_domain()) + return 0; + + ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared); + if (ret < 0) + return ret; + + /* + * Always allocate the space for the status frames in case + * we're migrated to a host with V2 support. + */ + ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status); + if (ret < 0) + goto err; + + return 0; +err: + arch_gnttab_vfree(&gnttab_shared_vm_area); + return -ENOMEM; +} + +#ifdef CONFIG_XEN_PVH +#include <xen/events.h> +#include <xen/xen-ops.h> +static int __init xen_pvh_gnttab_setup(void) +{ + if (!xen_pvh_domain()) + return -ENODEV; + + xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); + + return xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, + &xen_auto_xlat_grant_frames.vaddr, + xen_auto_xlat_grant_frames.count); +} +/* Call it _before_ __gnttab_init as we need to initialize the + * xen_auto_xlat_grant_frames first. */ +core_initcall(xen_pvh_gnttab_setup); +#endif |