x86/resctrl: Move get_corrected_mbm_count() into resctrl_arch_rmid_read()

resctrl_arch_rmid_read() is intended as the function that an
architecture agnostic resctrl filesystem driver can use to
read a value in bytes from a counter. Currently the function returns
the MBM values in chunks directly from hardware. When reading a bandwidth
counter, get_corrected_mbm_count() must be used to correct the
value read.

get_corrected_mbm_count() is architecture specific, this work should be
done in resctrl_arch_rmid_read().

Move the function calls. This allows the resctrl filesystems's chunks
value to be removed in favour of the architecture private version.

Signed-off-by: James Morse <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Jamie Iles <[email protected]>
Reviewed-by: Shaopeng Tan <[email protected]>
Reviewed-by: Reinette Chatre <[email protected]>
Tested-by: Xin Hao <[email protected]>
Tested-by: Shaopeng Tan <[email protected]>
Tested-by: Cristian Marussi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: James Morse

arch/x86/kernel/cpu/resctrl/internal.h

@@ -280,14 +280,12 @@ struct rftype {
 
 /**
  * struct mbm_state - status for each MBM counter in each domain
- * @chunks:	Total data moved (multiply by rdt_group.mon_scale to get bytes)
  * @prev_bw_chunks: Previous chunks value read for bandwidth calculation
  * @prev_bw:	The most recent bandwidth in MBps
  * @delta_bw:	Difference between the current and previous bandwidth
  * @delta_comp:	Indicates whether to compute the delta_bw
  */
 struct mbm_state {
-	u64	chunks;
 	u64	prev_bw_chunks;
 	u32	prev_bw;
 	u32	delta_bw;
@@ -297,10 +295,12 @@ struct mbm_state {
 /**
  * struct arch_mbm_state - values used to compute resctrl_arch_rmid_read()s
  *			   return value.
+ * @chunks:	Total data moved (multiply by rdt_group.mon_scale to get bytes)
  * @prev_msr:	Value of IA32_QM_CTR last time it was read for the RMID used to
  *		find this struct.
  */
 struct arch_mbm_state {
+	u64	chunks;
 	u64	prev_msr;
 };
 

arch/x86/kernel/cpu/resctrl/monitor.c

@@ -204,7 +204,9 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
 
 	am = get_arch_mbm_state(hw_dom, rmid, eventid);
 	if (am) {
-		*val = mbm_overflow_count(am->prev_msr, msr_val, hw_res->mbm_width);
+		am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
+						 hw_res->mbm_width);
+		*val = get_corrected_mbm_count(rmid, am->chunks);
 		am->prev_msr = msr_val;
 	} else {
 		*val = msr_val;
@@ -374,9 +376,7 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 		return 0;
 	}
 
-	m->chunks += tval;
-
-	rr->val += get_corrected_mbm_count(rmid, m->chunks);
+	rr->val += tval;
 
 	return 0;
 }