// SPDX-License-Identifier: GPL-2.0 #include <linux/types.h> #include <linux/crash_dump.h> #include <xen/interface/xen.h> #include <xen/hvm.h> #include "mmu.h" #ifdef CONFIG_PROC_VMCORE /* * This function is used in two contexts: * - the kdump kernel has to check whether a pfn of the crashed kernel * was a ballooned page. vmcore is using this function to decide * whether to access a pfn of the crashed kernel. * - the kexec kernel has to check whether a pfn was ballooned by the * previous kernel. If the pfn is ballooned, handle it properly. * Returns 0 if the pfn is not backed by a RAM page, the caller may * handle the pfn special in this case. */ static int xen_oldmem_pfn_is_ram(unsigned long pfn) { struct xen_hvm_get_mem_type a = { .domid = DOMID_SELF, .pfn = pfn, }; int ram; if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a)) return -ENXIO; switch (a.mem_type) { case HVMMEM_mmio_dm: ram = 0; break; case HVMMEM_ram_rw: case HVMMEM_ram_ro: default: ram = 1; break; } return ram; } #endif static void xen_hvm_exit_mmap(struct mm_struct *mm) { struct xen_hvm_pagetable_dying a; int rc; a.domid = DOMID_SELF; a.gpa = __pa(mm->pgd); rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); WARN_ON_ONCE(rc < 0); } static int is_pagetable_dying_supported(void) { struct xen_hvm_pagetable_dying a; int rc = 0; a.domid = DOMID_SELF; a.gpa = 0x00; rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); if (rc < 0) { printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n"); return 0; } return 1; } void __init xen_hvm_init_mmu_ops(void) { if (is_pagetable_dying_supported()) pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap; #ifdef CONFIG_PROC_VMCORE WARN_ON(register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram)); #endif }