Commit-ID: 1de72c706488b7be664a601cf3843bd01e327e58 Gitweb: https://git.kernel.org/tip/1de72c706488b7be664a601cf3843bd01e327e58 Author: Michael Kelley <mikelley@xxxxxxxxxxxxx> AuthorDate: Sun, 4 Nov 2018 03:48:57 +0000 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Sun, 4 Nov 2018 11:04:46 +0100 x86/hyper-v: Enable PIT shutdown quirk Hyper-V emulation of the PIT has a quirk such that the normal PIT shutdown path doesn't work, because clearing the counter register restarts the timer. Disable the counter clearing on PIT shutdown. Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: "gregkh@xxxxxxxxxxxxxxxxxxx" <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "devel@xxxxxxxxxxxxxxxxxxxxxx" <devel@xxxxxxxxxxxxxxxxxxxxxx> Cc: "daniel.lezcano@xxxxxxxxxx" <daniel.lezcano@xxxxxxxxxx> Cc: "virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx" <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx> Cc: "jgross@xxxxxxxx" <jgross@xxxxxxxx> Cc: "akataria@xxxxxxxxxx" <akataria@xxxxxxxxxx> Cc: "olaf@xxxxxxxxx" <olaf@xxxxxxxxx> Cc: "apw@xxxxxxxxxxxxx" <apw@xxxxxxxxxxxxx> Cc: vkuznets <vkuznets@xxxxxxxxxx> Cc: "jasowang@xxxxxxxxxx" <jasowang@xxxxxxxxxx> Cc: "marcelo.cerri@xxxxxxxxxxxxx" <marcelo.cerri@xxxxxxxxxxxxx> Cc: KY Srinivasan <kys@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/1541303219-11142-3-git-send-email-mikelley@xxxxxxxxxxxxx --- arch/x86/kernel/cpu/mshyperv.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 1c72f3819eb1..e81a2db42df7 100644 --- 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. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
