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authorDavid Woodhouse <dwmw@amazon.co.uk>2022-03-11 22:20:17 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-03-16 21:29:32 +0300
commitf6c46b1d62f8ffbf2cf6eb43ab0d277bd3f7e948 (patch)
tree0cde7c4c4268fa79333c5def36eecc6cb3dbf3a3
parenta759de6991b35ad437adba32b5f0cb2fd9e75929 (diff)
downloadlinux-f6c46b1d62f8ffbf2cf6eb43ab0d277bd3f7e948.tar.xz
PM: hibernate: Honour ACPI hardware signature by default for virtual guests
The ACPI specification says that OSPM should refuse to restore from hibernate if the hardware signature changes, and should boot from scratch. However, real BIOSes often vary the hardware signature in cases where we *do* want to resume from hibernate, so Linux doesn't follow the spec by default. However, in a virtual environment there's no reason for the VMM to vary the hardware signature *unless* it wants to trigger a clean reboot as defined by the ACPI spec. So enable the check by default if a hypervisor is detected. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--arch/x86/kernel/acpi/sleep.c23
-rw-r--r--drivers/acpi/sleep.c11
-rw-r--r--include/linux/acpi.h2
3 files changed, 25 insertions, 11 deletions
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 1e97f944b47d..3b7f4cdbf2e0 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -15,6 +15,7 @@
#include <asm/desc.h>
#include <asm/cacheflush.h>
#include <asm/realmode.h>
+#include <asm/hypervisor.h>
#include <linux/ftrace.h>
#include "../../realmode/rm/wakeup.h"
@@ -140,9 +141,9 @@ static int __init acpi_sleep_setup(char *str)
acpi_realmode_flags |= 4;
#ifdef CONFIG_HIBERNATION
if (strncmp(str, "s4_hwsig", 8) == 0)
- acpi_check_s4_hw_signature(1);
+ acpi_check_s4_hw_signature = 1;
if (strncmp(str, "s4_nohwsig", 10) == 0)
- acpi_check_s4_hw_signature(0);
+ acpi_check_s4_hw_signature = 0;
#endif
if (strncmp(str, "nonvs", 5) == 0)
acpi_nvs_nosave();
@@ -160,3 +161,21 @@ static int __init acpi_sleep_setup(char *str)
}
__setup("acpi_sleep=", acpi_sleep_setup);
+
+#if defined(CONFIG_HIBERNATION) && defined(CONFIG_HYPERVISOR_GUEST)
+static int __init init_s4_sigcheck(void)
+{
+ /*
+ * If running on a hypervisor, honour the ACPI specification
+ * by default and trigger a clean reboot when the hardware
+ * signature in FACS is changed after hibernation.
+ */
+ if (acpi_check_s4_hw_signature == -1 &&
+ !hypervisor_is_type(X86_HYPER_NATIVE))
+ acpi_check_s4_hw_signature = 1;
+
+ return 0;
+}
+/* This must happen before acpi_init() which is a subsys initcall */
+arch_initcall(init_s4_sigcheck);
+#endif
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index d4fbea91ab6b..74e54fd44b8e 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -869,12 +869,7 @@ static inline void acpi_sleep_syscore_init(void) {}
#ifdef CONFIG_HIBERNATION
static unsigned long s4_hardware_signature;
static struct acpi_table_facs *facs;
-static int sigcheck = -1; /* Default behaviour is just to warn */
-
-void __init acpi_check_s4_hw_signature(int check)
-{
- sigcheck = check;
-}
+int acpi_check_s4_hw_signature = -1; /* Default behaviour is just to warn */
static int acpi_hibernation_begin(pm_message_t stage)
{
@@ -999,7 +994,7 @@ static void acpi_sleep_hibernate_setup(void)
hibernation_set_ops(old_suspend_ordering ?
&acpi_hibernation_ops_old : &acpi_hibernation_ops);
sleep_states[ACPI_STATE_S4] = 1;
- if (!sigcheck)
+ if (!acpi_check_s4_hw_signature)
return;
acpi_get_table(ACPI_SIG_FACS, 1, (struct acpi_table_header **)&facs);
@@ -1011,7 +1006,7 @@ static void acpi_sleep_hibernate_setup(void)
*/
s4_hardware_signature = facs->hardware_signature;
- if (sigcheck > 0) {
+ if (acpi_check_s4_hw_signature > 0) {
/*
* If we're actually obeying the ACPI specification
* then the signature is written out as part of the
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 6274758648e3..766dbcb82df1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -526,7 +526,7 @@ acpi_status acpi_release_memory(acpi_handle handle, struct resource *res,
int acpi_resources_are_enforced(void);
#ifdef CONFIG_HIBERNATION
-void __init acpi_check_s4_hw_signature(int check);
+extern int acpi_check_s4_hw_signature;
#endif
#ifdef CONFIG_PM_SLEEP