1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/types.h> 3 #include <linux/crash_dump.h> 4 5 #include <xen/interface/xen.h> 6 #include <xen/hvm.h> 7 8 #include "xen-ops.h" 9 10 #ifdef CONFIG_PROC_VMCORE 11 /* 12 * The kdump kernel has to check whether a pfn of the crashed kernel 13 * was a ballooned page. vmcore is using this function to decide 14 * whether to access a pfn of the crashed kernel. 15 * Returns "false" if the pfn is not backed by a RAM page, the caller may 16 * handle the pfn special in this case. 17 */ 18 static bool xen_vmcore_pfn_is_ram(struct vmcore_cb *cb, unsigned long pfn) 19 { 20 struct xen_hvm_get_mem_type a = { 21 .domid = DOMID_SELF, 22 .pfn = pfn, 23 }; 24 25 if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a)) { 26 pr_warn_once("Unexpected HVMOP_get_mem_type failure\n"); 27 return true; 28 } 29 return a.mem_type != HVMMEM_mmio_dm; 30 } 31 static struct vmcore_cb xen_vmcore_cb = { 32 .pfn_is_ram = xen_vmcore_pfn_is_ram, 33 }; 34 #endif 35 36 static void xen_hvm_exit_mmap(struct mm_struct *mm) 37 { 38 struct xen_hvm_pagetable_dying a; 39 int rc; 40 41 a.domid = DOMID_SELF; 42 a.gpa = __pa(mm->pgd); 43 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); 44 WARN_ON_ONCE(rc < 0); 45 } 46 47 static int is_pagetable_dying_supported(void) 48 { 49 struct xen_hvm_pagetable_dying a; 50 int rc = 0; 51 52 a.domid = DOMID_SELF; 53 a.gpa = 0x00; 54 rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a); 55 if (rc < 0) { 56 printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n"); 57 return 0; 58 } 59 return 1; 60 } 61 62 void __init xen_hvm_init_mmu_ops(void) 63 { 64 if (is_pagetable_dying_supported()) 65 pv_ops.mmu.exit_mmap = xen_hvm_exit_mmap; 66 #ifdef CONFIG_PROC_VMCORE 67 register_vmcore_cb(&xen_vmcore_cb); 68 #endif 69 } 70