linux-kernel - [PATCH v2 06/12] x86/jailhouse: Enable PMTIMER

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Date:   Mon, 27 Nov 2017 09:11:48 +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 v2 06/12] 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>
Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
---
 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 93c67ae5cfaf..bbcbe21ca664 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -800,6 +800,7 @@ config PARAVIRT_CLOCK
 config JAILHOUSE_GUEST
 	bool "Jailhouse non-root cell support"
 	depends on 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 9682e7089402..267547162a2c 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>
@@ -93,6 +94,9 @@ static void __init jailhouse_init_platform(void)
 
 	if (setup_data.compatible_version > JAILHOUSE_SETUP_REQUIRED_VERSION)
 		panic("Jailhouse: Unsupported setup data structure");
+
+	pmtmr_ioport = setup_data.pm_timer_address;
+	pr_debug("Jailhouse: PM-Timer IO Port: %#x\n", pmtmr_ioport);
 }
 
 bool jailhouse_paravirt(void)
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 46505396869e..d650c5b6ec90 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)
@@ -564,3 +548,19 @@ 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