[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] 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; + } } -- generated by git-patchbot for /home/xen/git/xen.git#master
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