diff options
Diffstat (limited to 'arch/x86/xen/mmu.c')
| -rw-r--r-- | arch/x86/xen/mmu.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 5a16824cc2b3..963cb2df636a 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -47,6 +47,7 @@ #include <linux/gfp.h> #include <linux/memblock.h> #include <linux/seq_file.h> +#include <linux/crash_dump.h> #include <trace/events/xen.h> @@ -2381,6 +2382,43 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region); #ifdef CONFIG_XEN_PVHVM +#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; @@ -2411,6 +2449,9 @@ 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 + register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram); +#endif } #endif |