diff options
| author | Michael Kelley <mikelley@microsoft.com> | 2018-11-04 03:48:57 +0000 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2019-02-11 17:53:47 +0000 |
| commit | d6cb071e1f673aa26225ea731066e4cdd1dd2288 (patch) | |
| tree | 6c766d0c69dd1df6af21b70484c1c76059edd8ea /arch/x86 | |
| parent | 6dc5ad52fe628c39ceb3fe0c1d252bb082418c48 (diff) | |
x86/hyper-v: Enable PIT shutdown quirk
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@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>
Cc: "daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>
Cc: "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>
Cc: "jgross@suse.com" <jgross@suse.com>
Cc: "akataria@vmware.com" <akataria@vmware.com>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>
Cc: "apw@canonical.com" <apw@canonical.com>
Cc: vkuznets <vkuznets@redhat.com>
Cc: "jasowang@redhat.com" <jasowang@redhat.com>
Cc: "marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Cc: KY Srinivasan <kys@microsoft.com>
Link: https://lkml.kernel.org/r/1541303219-11142-3-git-send-email-mikelley@microsoft.com
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 939155ffdece..ffef5852fe4e 100644 --- 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_platform(void) 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 = { |