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authorDavid Hildenbrand <david@redhat.com>2021-11-08 18:31:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-09 10:02:48 -0800
commitcc5f2704c93456e6f1c671c5cf7b582a55df5484 (patch)
treef407b00013ea6cf043f9c3bfea7b2e262bb5d833 /arch/x86/xen/mmu_hvm.c
parent2c9feeaedfe1f34c4e327cb6f9b8b90052edced1 (diff)
proc/vmcore: convert oldmem_pfn_is_ram callback to more generic vmcore callbacks
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>
Diffstat (limited to 'arch/x86/xen/mmu_hvm.c')
-rw-r--r--arch/x86/xen/mmu_hvm.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/xen/mmu_hvm.c b/arch/x86/xen/mmu_hvm.c
index 6ba8826dcdcc..509bdee3ab90 100644
--- a/arch/x86/xen/mmu_hvm.c
+++ b/arch/x86/xen/mmu_hvm.c
@@ -12,10 +12,10 @@
* 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 0 if the pfn is not backed by a RAM page, the caller may
+ * Returns "false" 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)
+static bool xen_vmcore_pfn_is_ram(struct vmcore_cb *cb, unsigned long pfn)
{
struct xen_hvm_get_mem_type a = {
.domid = DOMID_SELF,
@@ -24,10 +24,13 @@ static int xen_oldmem_pfn_is_ram(unsigned long pfn)
if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a)) {
pr_warn_once("Unexpected HVMOP_get_mem_type failure\n");
- return -ENXIO;
+ 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)
@@ -61,6 +64,6 @@ 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
- WARN_ON(register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram));
+ register_vmcore_cb(&xen_vmcore_cb);
#endif
}