| 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 "mmu.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, arg: &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, arg: &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, arg: &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(cb: &xen_vmcore_cb); |
| 68 | #endif |
| 69 | } |
| 70 |