linux-kernel - [PATCH v1 7/9] x86/resctrl: Assign HW RMIDs to CPUs for soft RMID

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230421141723.2405942-8-peternewman@google.com>
Date:   Fri, 21 Apr 2023 16:17:21 +0200
From:   Peter Newman <peternewman@...gle.com>
To:     Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>
Cc:     Babu Moger <babu.moger@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Stephane Eranian <eranian@...gle.com>,
        James Morse <james.morse@....com>,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
        Peter Newman <peternewman@...gle.com>
Subject: [PATCH v1 7/9] x86/resctrl: Assign HW RMIDs to CPUs for soft RMID

To implement soft RMIDs, each CPU needs a HW RMID that is unique within
its L3 cache domain. This is the minimum number of RMIDs needed to
monitor all CPUs.

This is accomplished by determining the rank of each CPU's mask bit
within its L3 shared_cpu_mask in resctrl_online_cpu().

Signed-off-by: Peter Newman <peternewman@...gle.com>
---
 arch/x86/kernel/cpu/resctrl/core.c | 39 +++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 47b1c37a81f8..b0d873231b1e 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -596,6 +596,38 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 	}
 }
 
+/* Assign each CPU an RMID that is unique within its cache domain. */
+static u32 determine_hw_rmid_for_cpu(int cpu)
+{
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
+	struct cacheinfo *l3ci = NULL;
+	u32 rmid;
+	int i;
+
+	/* Locate the cacheinfo for this CPU's L3 cache. */
+	for (i = 0; i < ci->num_leaves; i++) {
+		if (ci->info_list[i].level == 3 &&
+		    (ci->info_list[i].attributes & CACHE_ID)) {
+			l3ci = &ci->info_list[i];
+			break;
+		}
+	}
+	WARN_ON(!l3ci);
+
+	if (!l3ci)
+		return 0;
+
+	/* Use the position of cpu in its shared_cpu_mask as its RMID. */
+	rmid = 0;
+	for_each_cpu(i, &l3ci->shared_cpu_map) {
+		if (i == cpu)
+			break;
+		rmid++;
+	}
+
+	return rmid;
+}
+
 static void clear_closid_rmid(int cpu)
 {
 	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
@@ -604,7 +636,12 @@ static void clear_closid_rmid(int cpu)
 	state->default_rmid = 0;
 	state->cur_closid = 0;
 	state->cur_rmid = 0;
-	wrmsr(MSR_IA32_PQR_ASSOC, 0, 0);
+	state->hw_rmid = 0;
+
+	if (static_branch_likely(&rdt_soft_rmid_enable_key))
+		state->hw_rmid = determine_hw_rmid_for_cpu(cpu);
+
+	wrmsr(MSR_IA32_PQR_ASSOC, state->hw_rmid, 0);
 }
 
 static int resctrl_online_cpu(unsigned int cpu)
-- 
2.40.0.634.g4ca3ef3211-goog