3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Michael Kelley <mikelley@xxxxxxxxxxxxx> commit 1de72c706488b7be664a601cf3843bd01e327e58 upstream. 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> Link: https://lkml.kernel.org/r/1541303219-11142-3-git-send-email-mikelley@xxxxxxxxxxxxx [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/mshyperv.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -18,6 +18,7 @@ #include <linux/efi.h> #include <linux/interrupt.h> #include <linux/irq.h> +#include <linux/i8253.h> #include <asm/processor.h> #include <asm/hypervisor.h> #include <asm/hyperv.h> @@ -143,6 +144,16 @@ static void __init ms_hyperv_init_platfo no_timer_check = 1; #endif + /* + * 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; + } const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
