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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/xsm: Improve fallback handling in xsm_fixup_ops()
commit ee3407bb05dae8fa2bbd6476e36bd96d352fd19e
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Nov 4 03:12:49 2021 +0000
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon Nov 29 13:53:05 2021 +0000
xen/xsm: Improve fallback handling in xsm_fixup_ops()
The current xsm_fixup_ops() is just shy of a full page when compiled, and
very
fragile to NULL function pointer errors.
Address both of these issues with a minor piece of structure (ab)use.
Introduce dummy_ops, and fix up the provided xsm_ops pointer by treating
both
as an array of unsigned longs.
The compiled size improvement speaks for itself:
$ ../scripts/bloat-o-meter xen-syms-before xen-syms-after
add/remove: 1/0 grow/shrink: 0/1 up/down: 712/-3897 (-3185)
Function old new delta
dummy_ops - 712 +712
xsm_fixup_ops 3987 90 -3897
and there is an additional safety check that will make it obvious during
development if there is an issue with the fallback handling.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
xen/include/xsm/xsm.h | 9 ++
xen/xsm/dummy.c | 254 +++++++++++++++++++++++++++-----------------------
2 files changed, 147 insertions(+), 116 deletions(-)
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index c5bd421349..5aa4dd588d 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -42,6 +42,15 @@ enum xsm_default {
};
typedef enum xsm_default xsm_default_t;
+/*
+ * !!! WARNING !!!
+ *
+ * For simplicity, xsm_fixup_ops() expects that this structure is made
+ * exclusively of function pointers to non-init functions. Think carefully
+ * before deviating from the pattern.
+ *
+ * !!! WARNING !!!
+ */
struct xsm_ops {
void (*security_domaininfo)(struct domain *d,
struct xen_domctl_getdomaininfo *info);
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 041f59fdf4..4d29a9aa5b 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -13,145 +13,167 @@
#define XSM_NO_WRAPPERS
#include <xsm/dummy.h>
-#define set_to_dummy_if_null(ops, function) \
- do { \
- if ( !ops->function ) \
- ops->function = xsm_##function; \
- } while (0)
-
-void __init xsm_fixup_ops (struct xsm_ops *ops)
-{
- set_to_dummy_if_null(ops, security_domaininfo);
- set_to_dummy_if_null(ops, domain_create);
- set_to_dummy_if_null(ops, getdomaininfo);
- set_to_dummy_if_null(ops, domctl_scheduler_op);
- set_to_dummy_if_null(ops, sysctl_scheduler_op);
- set_to_dummy_if_null(ops, set_target);
- set_to_dummy_if_null(ops, domctl);
- set_to_dummy_if_null(ops, sysctl);
- set_to_dummy_if_null(ops, readconsole);
-
- set_to_dummy_if_null(ops, evtchn_unbound);
- set_to_dummy_if_null(ops, evtchn_interdomain);
- set_to_dummy_if_null(ops, evtchn_close_post);
- set_to_dummy_if_null(ops, evtchn_send);
- set_to_dummy_if_null(ops, evtchn_status);
- set_to_dummy_if_null(ops, evtchn_reset);
-
- set_to_dummy_if_null(ops, grant_mapref);
- set_to_dummy_if_null(ops, grant_unmapref);
- set_to_dummy_if_null(ops, grant_setup);
- set_to_dummy_if_null(ops, grant_transfer);
- set_to_dummy_if_null(ops, grant_copy);
- set_to_dummy_if_null(ops, grant_query_size);
-
- set_to_dummy_if_null(ops, alloc_security_domain);
- set_to_dummy_if_null(ops, free_security_domain);
- set_to_dummy_if_null(ops, alloc_security_evtchns);
- set_to_dummy_if_null(ops, free_security_evtchns);
- set_to_dummy_if_null(ops, show_security_evtchn);
- set_to_dummy_if_null(ops, init_hardware_domain);
-
- set_to_dummy_if_null(ops, get_pod_target);
- set_to_dummy_if_null(ops, set_pod_target);
-
- set_to_dummy_if_null(ops, memory_exchange);
- set_to_dummy_if_null(ops, memory_adjust_reservation);
- set_to_dummy_if_null(ops, memory_stat_reservation);
- set_to_dummy_if_null(ops, memory_pin_page);
- set_to_dummy_if_null(ops, claim_pages);
-
- set_to_dummy_if_null(ops, console_io);
-
- set_to_dummy_if_null(ops, profile);
-
- set_to_dummy_if_null(ops, kexec);
- set_to_dummy_if_null(ops, schedop_shutdown);
-
- set_to_dummy_if_null(ops, show_irq_sid);
- set_to_dummy_if_null(ops, map_domain_pirq);
- set_to_dummy_if_null(ops, map_domain_irq);
- set_to_dummy_if_null(ops, unmap_domain_pirq);
- set_to_dummy_if_null(ops, unmap_domain_irq);
- set_to_dummy_if_null(ops, bind_pt_irq);
- set_to_dummy_if_null(ops, unbind_pt_irq);
- set_to_dummy_if_null(ops, irq_permission);
- set_to_dummy_if_null(ops, iomem_permission);
- set_to_dummy_if_null(ops, iomem_mapping);
- set_to_dummy_if_null(ops, pci_config_permission);
- set_to_dummy_if_null(ops, get_vnumainfo);
+static const struct xsm_ops __initconstrel dummy_ops = {
+ .security_domaininfo = xsm_security_domaininfo,
+ .domain_create = xsm_domain_create,
+ .getdomaininfo = xsm_getdomaininfo,
+ .domctl_scheduler_op = xsm_domctl_scheduler_op,
+ .sysctl_scheduler_op = xsm_sysctl_scheduler_op,
+ .set_target = xsm_set_target,
+ .domctl = xsm_domctl,
+ .sysctl = xsm_sysctl,
+ .readconsole = xsm_readconsole,
+
+ .evtchn_unbound = xsm_evtchn_unbound,
+ .evtchn_interdomain = xsm_evtchn_interdomain,
+ .evtchn_close_post = xsm_evtchn_close_post,
+ .evtchn_send = xsm_evtchn_send,
+ .evtchn_status = xsm_evtchn_status,
+ .evtchn_reset = xsm_evtchn_reset,
+
+ .grant_mapref = xsm_grant_mapref,
+ .grant_unmapref = xsm_grant_unmapref,
+ .grant_setup = xsm_grant_setup,
+ .grant_transfer = xsm_grant_transfer,
+ .grant_copy = xsm_grant_copy,
+ .grant_query_size = xsm_grant_query_size,
+
+ .alloc_security_domain = xsm_alloc_security_domain,
+ .free_security_domain = xsm_free_security_domain,
+ .alloc_security_evtchns = xsm_alloc_security_evtchns,
+ .free_security_evtchns = xsm_free_security_evtchns,
+ .show_security_evtchn = xsm_show_security_evtchn,
+ .init_hardware_domain = xsm_init_hardware_domain,
+
+ .get_pod_target = xsm_get_pod_target,
+ .set_pod_target = xsm_set_pod_target,
+
+ .memory_exchange = xsm_memory_exchange,
+ .memory_adjust_reservation = xsm_memory_adjust_reservation,
+ .memory_stat_reservation = xsm_memory_stat_reservation,
+ .memory_pin_page = xsm_memory_pin_page,
+ .claim_pages = xsm_claim_pages,
+
+ .console_io = xsm_console_io,
+
+ .profile = xsm_profile,
+
+ .kexec = xsm_kexec,
+ .schedop_shutdown = xsm_schedop_shutdown,
+
+ .show_irq_sid = xsm_show_irq_sid,
+ .map_domain_pirq = xsm_map_domain_pirq,
+ .map_domain_irq = xsm_map_domain_irq,
+ .unmap_domain_pirq = xsm_unmap_domain_pirq,
+ .unmap_domain_irq = xsm_unmap_domain_irq,
+ .bind_pt_irq = xsm_bind_pt_irq,
+ .unbind_pt_irq = xsm_unbind_pt_irq,
+ .irq_permission = xsm_irq_permission,
+ .iomem_permission = xsm_iomem_permission,
+ .iomem_mapping = xsm_iomem_mapping,
+ .pci_config_permission = xsm_pci_config_permission,
+ .get_vnumainfo = xsm_get_vnumainfo,
#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_PCI)
- set_to_dummy_if_null(ops, get_device_group);
- set_to_dummy_if_null(ops, assign_device);
- set_to_dummy_if_null(ops, deassign_device);
+ .get_device_group = xsm_get_device_group,
+ .assign_device = xsm_assign_device,
+ .deassign_device = xsm_deassign_device,
#endif
#if defined(CONFIG_HAS_PASSTHROUGH) && defined(CONFIG_HAS_DEVICE_TREE)
- set_to_dummy_if_null(ops, assign_dtdevice);
- set_to_dummy_if_null(ops, deassign_dtdevice);
+ .assign_dtdevice = xsm_assign_dtdevice,
+ .deassign_dtdevice = xsm_deassign_dtdevice,
#endif
- set_to_dummy_if_null(ops, resource_plug_core);
- set_to_dummy_if_null(ops, resource_unplug_core);
- set_to_dummy_if_null(ops, resource_plug_pci);
- set_to_dummy_if_null(ops, resource_unplug_pci);
- set_to_dummy_if_null(ops, resource_setup_pci);
- set_to_dummy_if_null(ops, resource_setup_gsi);
- set_to_dummy_if_null(ops, resource_setup_misc);
-
- set_to_dummy_if_null(ops, page_offline);
- set_to_dummy_if_null(ops, hypfs_op);
- set_to_dummy_if_null(ops, hvm_param);
- set_to_dummy_if_null(ops, hvm_param_altp2mhvm);
- set_to_dummy_if_null(ops, hvm_altp2mhvm_op);
-
- set_to_dummy_if_null(ops, do_xsm_op);
+ .resource_plug_core = xsm_resource_plug_core,
+ .resource_unplug_core = xsm_resource_unplug_core,
+ .resource_plug_pci = xsm_resource_plug_pci,
+ .resource_unplug_pci = xsm_resource_unplug_pci,
+ .resource_setup_pci = xsm_resource_setup_pci,
+ .resource_setup_gsi = xsm_resource_setup_gsi,
+ .resource_setup_misc = xsm_resource_setup_misc,
+
+ .page_offline = xsm_page_offline,
+ .hypfs_op = xsm_hypfs_op,
+ .hvm_param = xsm_hvm_param,
+ .hvm_param_altp2mhvm = xsm_hvm_param_altp2mhvm,
+ .hvm_altp2mhvm_op = xsm_hvm_altp2mhvm_op,
+
+ .do_xsm_op = xsm_do_xsm_op,
#ifdef CONFIG_COMPAT
- set_to_dummy_if_null(ops, do_compat_op);
+ .do_compat_op = xsm_do_compat_op,
#endif
- set_to_dummy_if_null(ops, add_to_physmap);
- set_to_dummy_if_null(ops, remove_from_physmap);
- set_to_dummy_if_null(ops, map_gmfn_foreign);
+ .add_to_physmap = xsm_add_to_physmap,
+ .remove_from_physmap = xsm_remove_from_physmap,
+ .map_gmfn_foreign = xsm_map_gmfn_foreign,
- set_to_dummy_if_null(ops, vm_event_control);
+ .vm_event_control = xsm_vm_event_control,
#ifdef CONFIG_MEM_ACCESS
- set_to_dummy_if_null(ops, mem_access);
+ .mem_access = xsm_mem_access,
#endif
#ifdef CONFIG_MEM_PAGING
- set_to_dummy_if_null(ops, mem_paging);
+ .mem_paging = xsm_mem_paging,
#endif
#ifdef CONFIG_MEM_SHARING
- set_to_dummy_if_null(ops, mem_sharing);
+ .mem_sharing = xsm_mem_sharing,
#endif
- set_to_dummy_if_null(ops, platform_op);
+ .platform_op = xsm_platform_op,
#ifdef CONFIG_X86
- set_to_dummy_if_null(ops, do_mca);
- set_to_dummy_if_null(ops, shadow_control);
- set_to_dummy_if_null(ops, mem_sharing_op);
- set_to_dummy_if_null(ops, apic);
- set_to_dummy_if_null(ops, machine_memory_map);
- set_to_dummy_if_null(ops, domain_memory_map);
- set_to_dummy_if_null(ops, mmu_update);
- set_to_dummy_if_null(ops, mmuext_op);
- set_to_dummy_if_null(ops, update_va_mapping);
- set_to_dummy_if_null(ops, priv_mapping);
- set_to_dummy_if_null(ops, ioport_permission);
- set_to_dummy_if_null(ops, ioport_mapping);
- set_to_dummy_if_null(ops, pmu_op);
+ .do_mca = xsm_do_mca,
+ .shadow_control = xsm_shadow_control,
+ .mem_sharing_op = xsm_mem_sharing_op,
+ .apic = xsm_apic,
+ .machine_memory_map = xsm_machine_memory_map,
+ .domain_memory_map = xsm_domain_memory_map,
+ .mmu_update = xsm_mmu_update,
+ .mmuext_op = xsm_mmuext_op,
+ .update_va_mapping = xsm_update_va_mapping,
+ .priv_mapping = xsm_priv_mapping,
+ .ioport_permission = xsm_ioport_permission,
+ .ioport_mapping = xsm_ioport_mapping,
+ .pmu_op = xsm_pmu_op,
#endif
- set_to_dummy_if_null(ops, dm_op);
- set_to_dummy_if_null(ops, xen_version);
- set_to_dummy_if_null(ops, domain_resource_map);
+ .dm_op = xsm_dm_op,
+ .xen_version = xsm_xen_version,
+ .domain_resource_map = xsm_domain_resource_map,
#ifdef CONFIG_ARGO
- set_to_dummy_if_null(ops, argo_enable);
- set_to_dummy_if_null(ops, argo_register_single_source);
- set_to_dummy_if_null(ops, argo_register_any_source);
- set_to_dummy_if_null(ops, argo_send);
+ .argo_enable = xsm_argo_enable,
+ .argo_register_single_source = xsm_argo_register_single_source,
+ .argo_register_any_source = xsm_argo_register_any_source,
+ .argo_send = xsm_argo_send,
#endif
+};
+
+void __init xsm_fixup_ops(struct xsm_ops *ops)
+{
+ /*
+ * We make some simplifying assumptions about struct xsm_ops; that it is
+ * made exclusively of function pointers to non-init text.
+ *
+ * This allows us to walk over struct xsm_ops as if it were an array of
+ * unsigned longs.
+ */
+ unsigned long *dst = _p(ops);
+ const unsigned long *src = _p(&dummy_ops);
+
+ for ( ; dst < (unsigned long *)(ops + 1); src++, dst++ )
+ {
+ /*
+ * If you encounter this BUG(), then you've most likely added a new
+ * XSM hook but failed to provide the default implementation in
+ * dummy_ops.
+ *
+ * If not, then perhaps a function pointer to an init function, or
+ * something which isn't a function pointer at all.
+ */
+ BUG_ON(!is_kernel_text(*src));
+
+ if ( !*dst )
+ *dst = *src;
+ }
}
--
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