x86,fs/resctrl: Improve domain type checking

Every resctrl resource has a list of domain structures. struct rdt_ctrl_domain
and struct rdt_mon_domain both begin with struct rdt_domain_hdr with
rdt_domain_hdr::type used in validity checks before accessing the domain of
a particular type.

Add the resource id to struct rdt_domain_hdr in preparation for a new monitoring
domain structure that will be associated with a new monitoring resource. Improve
existing domain validity checks with a new helper domain_header_is_valid()
that checks both domain type and resource id.  domain_header_is_valid() should
be used before every call to container_of() that accesses a domain structure.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 3792ab4819dc62e10e46aaf9cbcfb4e397093976..0b8b7b8697a72cc50ab806a43768c7a343737f6e 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -464,7 +464,7 @@ static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
 
        hdr = resctrl_find_domain(&r->ctrl_domains, id, &add_pos);
        if (hdr) {
-               if (WARN_ON_ONCE(hdr->type != RESCTRL_CTRL_DOMAIN))
+               if (!domain_header_is_valid(hdr, RESCTRL_CTRL_DOMAIN, r->rid))
                        return;
                d = container_of(hdr, struct rdt_ctrl_domain, hdr);
 
@@ -481,6 +481,7 @@ static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
        d = &hw_dom->d_resctrl;
        d->hdr.id = id;
        d->hdr.type = RESCTRL_CTRL_DOMAIN;
+       d->hdr.rid = r->rid;
        cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
 
        rdt_domain_reconfigure_cdp(r);
@@ -520,7 +521,7 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
 
        hdr = resctrl_find_domain(&r->mon_domains, id, &add_pos);
        if (hdr) {
-               if (WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN))
+               if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
                        return;
                d = container_of(hdr, struct rdt_mon_domain, hdr);
 
@@ -538,6 +539,7 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
        d = &hw_dom->d_resctrl;
        d->hdr.id = id;
        d->hdr.type = RESCTRL_MON_DOMAIN;
+       d->hdr.rid = r->rid;
        ci = get_cpu_cacheinfo_level(cpu, RESCTRL_L3_CACHE);
        if (!ci) {
                pr_warn_once("Can't find L3 cache for CPU:%d resource %s\n", cpu, r->name);
@@ -598,7 +600,7 @@ static void domain_remove_cpu_ctrl(int cpu, struct rdt_resource *r)
                return;
        }
 
-       if (WARN_ON_ONCE(hdr->type != RESCTRL_CTRL_DOMAIN))
+       if (!domain_header_is_valid(hdr, RESCTRL_CTRL_DOMAIN, r->rid))
                return;
 
        d = container_of(hdr, struct rdt_ctrl_domain, hdr);
@@ -644,7 +646,7 @@ static void domain_remove_cpu_mon(int cpu, struct rdt_resource *r)
                return;
        }
 
-       if (WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN))
+       if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, r->rid))
                return;
 
        d = container_of(hdr, struct rdt_mon_domain, hdr);

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index b2d178d3556ecb4bcf99a86f8c0bcd96aef278bb..905c310de57327a63b5f0afecd138a05a53533be 100644 (file)
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -653,7 +653,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
                 * the resource to find the domain with "domid".
                 */
                hdr = resctrl_find_domain(&r->mon_domains, domid, NULL);
-               if (!hdr || WARN_ON_ONCE(hdr->type != RESCTRL_MON_DOMAIN)) {
+               if (!hdr || !domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, resid)) {
                        ret = -ENOENT;
                        goto out;
                }

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 54701668b3dfc0363811bd8174908e1e7af76c6f..e7c218f8d4f77d7e06287c28972a784abb5ee7fd 100644 (file)
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -131,15 +131,24 @@ enum resctrl_domain_type {
  * @list:              all instances of this resource
  * @id:                        unique id for this instance
  * @type:              type of this instance
+ * @rid:               resource id for this instance
  * @cpu_mask:          which CPUs share this resource
  */
 struct rdt_domain_hdr {
        struct list_head                list;
        int                             id;
        enum resctrl_domain_type        type;
+       enum resctrl_res_level          rid;
        struct cpumask                  cpu_mask;
 };
 
+static inline bool domain_header_is_valid(struct rdt_domain_hdr *hdr,
+                                         enum resctrl_domain_type type,
+                                         enum resctrl_res_level rid)
+{
+       return !WARN_ON_ONCE(hdr->type != type || hdr->rid != rid);
+}
+
 /**
  * struct rdt_ctrl_domain - group of CPUs sharing a resctrl control resource
  * @hdr:               common header for different domain types