linux-kernel - [PATCH 8/9] x86/hreset: Configure history reset

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Date: Fri,  2 Feb 2024 20:05:14 -0800
From: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc: Len Brown <len.brown@...el.com>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Stanislaw Gruszka <stanislaw.gruszka@...ux.intel.com>,
	Zhao Liu <zhao1.liu@...el.com>,
	Zhuocheng Ding <zhuocheng.ding@...el.com>,
	x86@...nel.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
	Zhao Liu <zhao1.liu@...ux.intel.com>
Subject: [PATCH 8/9] x86/hreset: Configure history reset

Configure the MSR that controls the behavior of HRESET on each logical
processor.

Cc: Len Brown <len.brown@...el.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc: Stanislaw Gruszka <stanislaw.gruszka@...ux.intel.com>
Cc: Zhao Liu <zhao1.liu@...ux.intel.com>
Cc: Zhuocheng Ding <zhuocheng.ding@...el.com>
Cc: x86@...nel.org
Cc: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
---
Patch cherry-picked from the IPC classes patchset
---
---
 arch/x86/kernel/cpu/common.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 0b97bcde70c6..bce8719b47c9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -381,6 +381,26 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c)
 	cr4_clear_bits(X86_CR4_UMIP);
 }
 
+static u32 hardware_history_features __ro_after_init;
+
+static __always_inline void setup_hreset(struct cpuinfo_x86 *c)
+{
+	if (!cpu_feature_enabled(X86_FEATURE_HRESET))
+		return;
+
+	/*
+	 * Use on all CPUs the hardware history features that the boot
+	 * CPU supports.
+	 */
+	if (c == &boot_cpu_data)
+		hardware_history_features = cpuid_ebx(0x20);
+
+	if (!hardware_history_features)
+		return;
+
+	wrmsrl(MSR_IA32_HW_HRESET_ENABLE, hardware_history_features);
+}
+
 /* These bits should not change their value after CPU init is finished. */
 static const unsigned long cr4_pinned_mask =
 	X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP |
@@ -1872,10 +1892,11 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 	/* Disable the PN if appropriate */
 	squash_the_stupid_serial_number(c);
 
-	/* Set up SMEP/SMAP/UMIP */
+	/* Set up SMEP/SMAP/UMIP/HRESET */
 	setup_smep(c);
 	setup_smap(c);
 	setup_umip(c);
+	setup_hreset(c);
 
 	/* Enable FSGSBASE instructions if available. */
 	if (cpu_has(c, X86_FEATURE_FSGSBASE)) {
-- 
2.25.1