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authorTianyu Lan <Tianyu.Lan@microsoft.com>2019-08-14 20:32:16 +0800
committerThomas Gleixner <tglx@linutronix.de>2019-08-23 16:59:54 +0200
commitbd00cd52d5be655a2f217e2ed74b91a71cb2b14f (patch)
tree90b8fe8d71a849f6066d1c2ba7500dba0fca9819 /arch
parentadb87ff4f96c9700718e09c97a804124d5cd61ff (diff)
downloadlinux-bd00cd52d5be655a2f217e2ed74b91a71cb2b14f.tar.bz2
clocksource/drivers/hyperv: Add Hyper-V specific sched clock function
Hyper-V guests use the default native_sched_clock() in pv_ops.time.sched_clock on x86. But native_sched_clock() directly uses the raw TSC value, which can be discontinuous in a Hyper-V VM. Add the generic hv_setup_sched_clock() to set the sched clock function appropriately. On x86, this sets pv_ops.time.sched_clock to read the Hyper-V reference TSC value that is scaled and adjusted to be continuous. Also move the Hyper-V reference TSC initialization much earlier in the boot process so no discontinuity is observed when pv_ops.time.sched_clock calculates its offset. [ tglx: Folded build fix ] Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lkml.kernel.org/r/20190814123216.32245-3-Tianyu.Lan@microsoft.com
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/hyperv/hv_init.c2
-rw-r--r--arch/x86/kernel/cpu/mshyperv.c8
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 0d258688c8cf..866dfb3dca48 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -301,8 +301,6 @@ void __init hyperv_init(void)
x86_init.pci.arch_init = hv_pci_init;
- /* Register Hyper-V specific clocksource */
- hv_init_clocksource();
return;
remove_cpuhp_state:
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 062f77279ce3..53afd33990eb 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -29,6 +29,7 @@
#include <asm/timer.h>
#include <asm/reboot.h>
#include <asm/nmi.h>
+#include <clocksource/hyperv_timer.h>
struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);
@@ -338,9 +339,16 @@ static void __init ms_hyperv_init_platform(void)
x2apic_phys = 1;
# endif
+ /* Register Hyper-V specific clocksource */
+ hv_init_clocksource();
#endif
}
+void hv_setup_sched_clock(void *sched_clock)
+{
+ pv_ops.time.sched_clock = sched_clock;
+}
+
const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,