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authorVitaly Kuznetsov <vkuznets@redhat.com>2018-01-24 14:23:34 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-01-30 23:55:33 +0100
commite7c4e36c447daca2b7df49024f6bf230871cb155 (patch)
tree07cc285ccc5ed84a766a2ebb1f3cfb2525333ade /arch/x86/hyperv
parent93286261de1b46339aa27cd4c639b21778f6cade (diff)
downloadlinux-e7c4e36c447daca2b7df49024f6bf230871cb155.tar.bz2
x86/hyperv: Redirect reenlightment notifications on CPU offlining
It is very unlikely for CPUs to get offlined when running on Hyper-V as there is a protection in the vmbus module which prevents it when the guest has any VMBus devices assigned. This, however, may change in future if an option to reassign an already active channel will be added. It is also possible to run without any Hyper-V devices or to have a CPU with no assigned channels. Reassign reenlightenment notifications to some other active CPU when the CPU which is assigned to them goes offline. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: kvm@vger.kernel.org Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com> Cc: Roman Kagan <rkagan@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: devel@linuxdriverproject.org Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Cathy Avery <cavery@redhat.com> Cc: Mohammed Gamal <mmorsy@redhat.com> Link: https://lkml.kernel.org/r/20180124132337.30138-5-vkuznets@redhat.com
Diffstat (limited to 'arch/x86/hyperv')
-rw-r--r--arch/x86/hyperv/hv_init.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 712ac40081f7..e4377e2f2a10 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -191,6 +191,26 @@ void clear_hv_tscchange_cb(void)
}
EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
+static int hv_cpu_die(unsigned int cpu)
+{
+ struct hv_reenlightenment_control re_ctrl;
+ unsigned int new_cpu;
+
+ if (hv_reenlightenment_cb == NULL)
+ return 0;
+
+ rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+ if (re_ctrl.target_vp == hv_vp_index[cpu]) {
+ /* Reassign to some other online CPU */
+ new_cpu = cpumask_any_but(cpu_online_mask, cpu);
+
+ re_ctrl.target_vp = hv_vp_index[new_cpu];
+ wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+ }
+
+ return 0;
+}
+
/*
* This function is to be invoked early in the boot sequence after the
* hypervisor has been detected.
@@ -220,7 +240,7 @@ void hyperv_init(void)
return;
if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
- hv_cpu_init, NULL) < 0)
+ hv_cpu_init, hv_cpu_die) < 0)
goto free_vp_index;
/*