Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...

[sfrench/cifs-2.6.git] / arch / x86 / kernel / cpu / mshyperv.c

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 1c72f3819eb123d8fb7271a0c49cf94aceae5ee3..e81a2db42df7ba0d6fb28d9b0b2fcf0340bbd585 100644 (file)
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -20,6 +20,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kexec.h>
+#include <linux/i8253.h>
 #include <asm/processor.h>
 #include <asm/hypervisor.h>
 #include <asm/hyperv-tlfs.h>
@@ -295,6 +296,16 @@ static void __init ms_hyperv_init_platform(void)
        if (efi_enabled(EFI_BOOT))
                x86_platform.get_nmi_reason = hv_get_nmi_reason;
 
+       /*
+        * Hyper-V VMs have a PIT emulation quirk such that zeroing the
+        * counter register during PIT shutdown restarts the PIT. So it
+        * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
+        * to false tells pit_shutdown() not to zero the counter so that
+        * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
+        * and setting this value has no effect.
+        */
+       i8253_clear_counter_on_shutdown = false;
+
 #if IS_ENABLED(CONFIG_HYPERV)
        /*
         * Setup the hook to get control post apic initialization.