linux-kernel - [PATCH 04/10] x86: jailhouse: Enable PMTIMER

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Message-Id: <903f5eedb46e55da7479ed541112acae25d64240.1510817211.git.jan.kiszka@siemens.com>
Date:   Thu, 16 Nov 2017 08:26:46 +0100
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        jailhouse-dev@...glegroups.com
Subject: [PATCH 04/10] x86: jailhouse: Enable PMTIMER

From: Jan Kiszka <jan.kiszka@...mens.com>

Jailhouse exposes the PMTIMER as only reference clock to all cells. Pick
up its address from the setup data. Allow to enable the Linux support of
it by relaxing its strict dependency on ACPI.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---
 arch/x86/Kconfig            |  1 +
 arch/x86/kernel/jailhouse.c |  4 ++++
 drivers/acpi/Kconfig        | 32 ++++++++++++++++----------------
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c5f4f4683b51..6976c035ea63 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -785,6 +785,7 @@ config KVM_DEBUG_FS
 config JAILHOUSE_GUEST
 	bool "Jailhouse non-root cell support"
 	depends on PARAVIRT && X86_64
+	select X86_PM_TIMER
 	---help---
 	  This option allows to run Linux as guest in a Jailhouse non-root
 	  cell. You can leave this option disabled if you only want to start
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index ce9416c70656..f7e99f7a8873 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -10,6 +10,7 @@
  * the COPYING file in the top-level directory.
  */
 
+#include <linux/acpi_pmtmr.h>
 #include <linux/kernel.h>
 #include <asm/apic.h>
 #include <asm/cpu.h>
@@ -66,6 +67,9 @@ static void __init jailhouse_init_platform(void)
 	    data->compatible_version > SETUP_REQUIRED_VERSION)
 		panic("Jailhouse: Unsupported setup data structure");
 
+	pmtmr_ioport = data->pm_timer_address;
+	pr_debug("Jailhouse: PM-Timer IO Port: %#x\n", pmtmr_ioport);
+
 #ifdef CONFIG_X86_X2APIC
 	/*
 	 * Register x2APIC handlers early. We need them when running
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 91477d5ab422..c054f9b4f1eb 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -361,22 +361,6 @@ config ACPI_PCI_SLOT
 	  i.e., segment/bus/device/function tuples, with physical slots in
 	  the system.  If you are unsure, say N.
 
-config X86_PM_TIMER
-	bool "Power Management Timer Support" if EXPERT
-	depends on X86
-	default y
-	help
-	  The Power Management Timer is available on all ACPI-capable,
-	  in most cases even if ACPI is unusable or blacklisted.
-
-	  This timing source is not affected by power management features
-	  like aggressive processor idling, throttling, frequency and/or
-	  voltage scaling, unlike the commonly used Time Stamp Counter
-	  (TSC) timing source.
-
-	  You should nearly always say Y here because many modern
-	  systems require this timer. 
-
 config ACPI_CONTAINER
 	bool "Container and Module Devices"
 	default (ACPI_HOTPLUG_MEMORY || ACPI_HOTPLUG_CPU)
@@ -558,3 +542,19 @@ config TPS68470_PMIC_OPREGION
 	  using this, are probed.
 
 endif	# ACPI
+
+config X86_PM_TIMER
+	bool "Power Management Timer Support" if EXPERT
+	depends on X86 && (ACPI || JAILHOUSE_GUEST)
+	default y
+	help
+	  The Power Management Timer is available on all ACPI-capable,
+	  in most cases even if ACPI is unusable or blacklisted.
+
+	  This timing source is not affected by power management features
+	  like aggressive processor idling, throttling, frequency and/or
+	  voltage scaling, unlike the commonly used Time Stamp Counter
+	  (TSC) timing source.
+
+	  You should nearly always say Y here because many modern
+	  systems require this timer.
-- 
2.12.3