mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-31 00:17:44 +00:00
cc5f2704c9
Let's support multiple registered callbacks, making sure that registering vmcore callbacks cannot fail. Make the callback return a bool instead of an int, handling how to deal with errors internally. Drop unused HAVE_OLDMEM_PFN_IS_RAM. We soon want to make use of this infrastructure from other drivers: virtio-mem, registering one callback for each virtio-mem device, to prevent reading unplugged virtio-mem memory. Handle it via a generic vmcore_cb structure, prepared for future extensions: for example, once we support virtio-mem on s390x where the vmcore is completely constructed in the second kernel, we want to detect and add plugged virtio-mem memory ranges to the vmcore in order for them to get dumped properly. Handle corner cases that are unexpected and shouldn't happen in sane setups: registering a callback after the vmcore has already been opened (warn only) and unregistering a callback after the vmcore has already been opened (warn and essentially read only zeroes from that point on). Link: https://lkml.kernel.org/r/20211005121430.30136-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Young <dyoung@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
69 lines
1.6 KiB
C
69 lines
1.6 KiB
C
// 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
|
|
/*
|
|
* 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.
|
|
* Returns "false" if the pfn is not backed by a RAM page, the caller may
|
|
* handle the pfn special in this case.
|
|
*/
|
|
static bool xen_vmcore_pfn_is_ram(struct vmcore_cb *cb, unsigned long pfn)
|
|
{
|
|
struct xen_hvm_get_mem_type a = {
|
|
.domid = DOMID_SELF,
|
|
.pfn = pfn,
|
|
};
|
|
|
|
if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a)) {
|
|
pr_warn_once("Unexpected HVMOP_get_mem_type failure\n");
|
|
return true;
|
|
}
|
|
return a.mem_type != HVMMEM_mmio_dm;
|
|
}
|
|
static struct vmcore_cb xen_vmcore_cb = {
|
|
.pfn_is_ram = xen_vmcore_pfn_is_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_ops.mmu.exit_mmap = xen_hvm_exit_mmap;
|
|
#ifdef CONFIG_PROC_VMCORE
|
|
register_vmcore_cb(&xen_vmcore_cb);
|
|
#endif
|
|
}
|