x86/jailhouse: Enable PMTIMER

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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: [email protected] Link: https://lkml.kernel.org/r/6d5c3fadd801eb3fba9510e2d3db14a9c404a1a0.1511770314.git.jan.kiszka@siemens.com
cail · Jan 14, 2018 · 87e65d0 · 87e65d0
1 parent 11c8dc4
commit 87e65d0
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Showing 3 changed files with 21 additions and 16 deletions.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
@@ -799,6 +799,7 @@ 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
@@ -8,6 +8,7 @@
  *  Jan Kiszka <[email protected]>
  */
 
+#include <linux/acpi_pmtmr.h>
 #include <linux/kernel.h>
 #include <asm/apic.h>
 #include <asm/cpu.h>
@@ -91,6 +92,9 @@ 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
@@ -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.