[PATCH v2 15/24] x86/resctrl: Add a helper to read a closid's configuration

James Morse
2021-03-12T18:01:08Z

The hardware configuration may look completely different to the
values resctrl gets from user-space. The staged configuration
and resctrl_arch_update_domains() allow the architecture to
convert or translate these values.
(e.g. Arm's MPAM may back MBA's percentage control using the
'BWPBM' bitmap)

Resctrl shouldn't read or write the ctrl_val[] values directly. As a
step towards taking direct access away, add a helper to read the
current configuration.

This will allow another architecture to scale the bitmaps if
necessary, and possibly use controls that don't take the user-space
control format at all.

Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Signed-off-by: James Morse <james.morse@arm.com>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 16 ++++++---
arch/x86/kernel/cpu/resctrl/monitor.c | 6 +++-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 43 ++++++++++-------------
include/linux/resctrl.h | 2 ++
4 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 271f5d28412a..1cd54402b02a 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -401,22 +401,30 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
return ret ?: nbytes;
}

+void resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
+ u32 closid, u32 *value)
+{
+ struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
+
+ if (!is_mba_sc(r))
+ *value = hw_dom->ctrl_val[closid];
+ else
+ *value = hw_dom->mbps_val[closid];
+}
+
static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int closid)
{
struct rdt_resource *r = schema->res;
- struct rdt_hw_domain *hw_dom;
struct rdt_domain *dom;
bool sep = false;
u32 ctrl_val;

seq_printf(s, "%*s:", max_name_width, schema->name);
list_for_each_entry(dom, &r->domains, list) {
- hw_dom = resctrl_to_arch_dom(dom);
if (sep)
seq_puts(s, ";");

- ctrl_val = (!is_mba_sc(r) ? hw_dom->ctrl_val[closid] :
- hw_dom->mbps_val[closid]);
+ resctrl_arch_get_config(r, dom, closid, &ctrl_val);
seq_printf(s, r->format_str, dom->id, max_data_width,
ctrl_val);
sep = true;
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 6f700ff1b64c..c4d146658b44 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -442,8 +442,12 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
hw_dom_mba = resctrl_to_arch_dom(dom_mba);

cur_bw = pmbm_data->prev_bw;
- user_bw = hw_dom_mba->mbps_val[closid];
+ resctrl_arch_get_config(r_mba, dom_mba, closid, &user_bw);
delta_bw = pmbm_data->delta_bw;
+ /*
+ * resctrl_arch_get_config() chooses the mbps/ctrl value to return
+ * based on is_mba_sc(). For now, reach into the hw_dom.
+ */
cur_msr_val = hw_dom_mba->ctrl_val[closid];

/*
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index a103ed4f29fa..340bbeabb994 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -910,27 +910,27 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
int i, hwb, swb, excl, psl;
enum rdtgrp_mode mode;
bool sep = false;
- u32 *ctrl;
+ u32 ctrl_val;

mutex_lock(&rdtgroup_mutex);
hw_shareable = r->cache.shareable_bits;
list_for_each_entry(dom, &r->domains, list) {
if (sep)
seq_putc(seq, ';');
- ctrl = resctrl_to_arch_dom(dom)->ctrl_val;
sw_shareable = 0;
exclusive = 0;
seq_printf(seq, "%d=", dom->id);
- for (i = 0; i < closids_supported(); i++, ctrl++) {
+ for (i = 0; i < closids_supported(); i++) {
if (!closid_allocated(i))
continue;
+ resctrl_arch_get_config(r, dom, i, &ctrl_val);
mode = rdtgroup_mode_by_closid(i);
switch (mode) {
case RDT_MODE_SHAREABLE:
- sw_shareable |= *ctrl;
+ sw_shareable |= ctrl_val;
break;
case RDT_MODE_EXCLUSIVE:
- exclusive |= *ctrl;
+ exclusive |= ctrl_val;
break;
case RDT_MODE_PSEUDO_LOCKSETUP:
/*
@@ -1188,7 +1188,6 @@ static bool __rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d
{
enum rdtgrp_mode mode;
unsigned long ctrl_b;
- u32 *ctrl;
int i;

/* Check for any overlap with regions used by hardware directly */
@@ -1199,9 +1198,8 @@ static bool __rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d
}

/* Check for overlap with other resource groups */
- ctrl = resctrl_to_arch_dom(d)->ctrl_val;
- for (i = 0; i < closids_supported(); i++, ctrl++) {
- ctrl_b = *ctrl;
+ for (i = 0; i < closids_supported(); i++) {
+ resctrl_arch_get_config(r, d, i, (u32 *)&ctrl_b);
mode = rdtgroup_mode_by_closid(i);
if (closid_allocated(i) && i != closid &&
mode != RDT_MODE_PSEUDO_LOCKSETUP) {
@@ -1269,12 +1267,12 @@ bool rdtgroup_cbm_overlaps(struct resctrl_schema *s, struct rdt_domain *d,
*/
static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
{
- struct rdt_hw_domain *hw_dom;
int closid = rdtgrp->closid;
struct resctrl_schema *s;
struct rdt_resource *r;
bool has_cache = false;
struct rdt_domain *d;
+ u32 ctrl;

list_for_each_entry(s, &resctrl_schema_all, list) {
r = s->res;
@@ -1282,10 +1280,8 @@ static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
continue;
has_cache = true;
list_for_each_entry(d, &r->domains, list) {
- hw_dom = resctrl_to_arch_dom(d);
- if (rdtgroup_cbm_overlaps(s, d,
- hw_dom->ctrl_val[closid],
- rdtgrp->closid, false)) {
+ resctrl_arch_get_config(r, d, closid, &ctrl);
+ if (rdtgroup_cbm_overlaps(s, d, ctrl, closid, false)) {
rdt_last_cmd_puts("Schemata overlaps\n");
return false;
}
@@ -1417,7 +1413,6 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct resctrl_schema *schema;
- struct rdt_hw_domain *hw_dom;
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
struct rdt_domain *d;
@@ -1453,15 +1448,13 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
sep = false;
seq_printf(s, "%*s:", max_name_width, schema->name);
list_for_each_entry(d, &r->domains, list) {
- hw_dom = resctrl_to_arch_dom(d);
if (sep)
seq_putc(s, ';');
if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
size = 0;
} else {
- ctrl = (!is_mba_sc(r) ?
- hw_dom->ctrl_val[rdtgrp->closid] :
- hw_dom->mbps_val[rdtgrp->closid]);
+ resctrl_arch_get_config(r, d, rdtgrp->closid,
+ &ctrl);
if (r->rid == RDT_RESOURCE_MBA)
size = ctrl;
else
@@ -2736,7 +2729,7 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct resctrl_schema *s,
u32 used_b = 0, unused_b = 0;
unsigned long tmp_cbm;
enum rdtgrp_mode mode;
- u32 peer_ctl, *ctrl;
+ u32 peer_ctl, ctrl_val;
int i;

rdt_cdp_peer_get(r, d, &r_cdp, &d_cdp);
@@ -2744,8 +2737,7 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct resctrl_schema *s,
cfg->have_new_ctrl = false;
cfg->new_ctrl = r->cache.shareable_bits;
used_b = r->cache.shareable_bits;
- ctrl = resctrl_to_arch_dom(d)->ctrl_val;
- for (i = 0; i < closids_supported(); i++, ctrl++) {
+ for (i = 0; i < closids_supported(); i++) {
if (closid_allocated(i) && i != closid) {
mode = rdtgroup_mode_by_closid(i);
if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
@@ -2761,12 +2753,13 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct resctrl_schema *s,
* with an exclusive group.
*/
if (d_cdp)
- peer_ctl = resctrl_to_arch_dom(d_cdp)->ctrl_val[i];
+ resctrl_arch_get_config(r_cdp, d_cdp, i, &peer_ctl);
else
peer_ctl = 0;
- used_b |= *ctrl | peer_ctl;
+ resctrl_arch_get_config(r, d, i, &ctrl_val);
+ used_b |= ctrl_val | peer_ctl;
if (mode == RDT_MODE_SHAREABLE)
- cfg->new_ctrl |= *ctrl | peer_ctl;
+ cfg->new_ctrl |= ctrl_val | peer_ctl;
}
}
if (d->plr && d->plr->cbm > 0)
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index a6d2d7a25293..dec27b03675e 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -191,5 +191,7 @@ struct resctrl_schema {
/* The number of closid supported by this resource regardless of CDP */
u32 resctrl_arch_get_num_closid(struct rdt_resource *r);
int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid);
+void resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
+ u32 closid, u32 *value);

#endif /* _RESCTRL_H */
--
2.30.0