X86/Hyper-V: Enable IPI enlightenments
Hyper-V supports hypercalls to implement IPI; use them.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Cc: olaf@aepfle.de
Cc: sthemmin@microsoft.com
Cc: gregkh@linuxfoundation.org
Cc: jasowang@redhat.com
Cc: Michael.H.Kelley@microsoft.com
Cc: hpa@zytor.com
Cc: apw@canonical.com
Cc: devel@linuxdriverproject.org
Cc: vkuznets@redhat.com
Link: https://lkml.kernel.org/r/20180516215334.6547-2-kys@linuxonhyperv.com
diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
index ca20e31..3e0de61 100644
--- a/arch/x86/hyperv/hv_apic.c
+++ b/arch/x86/hyperv/hv_apic.c
@@ -33,6 +33,8 @@
#ifdef CONFIG_X86_64
#if IS_ENABLED(CONFIG_HYPERV)
+static struct apic orig_apic;
+
static u64 hv_apic_icr_read(void)
{
u64 reg_val;
@@ -88,8 +90,123 @@
wrmsr(HV_X64_MSR_EOI, val, 0);
}
+/*
+ * IPI implementation on Hyper-V.
+ */
+static bool __send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ int cur_cpu, vcpu;
+ struct ipi_arg_non_ex **arg;
+ struct ipi_arg_non_ex *ipi_arg;
+ int ret = 1;
+ unsigned long flags;
+
+ if (cpumask_empty(mask))
+ return true;
+
+ if (!hv_hypercall_pg)
+ return false;
+
+ if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
+ return false;
+
+ local_irq_save(flags);
+ arg = (struct ipi_arg_non_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
+
+ ipi_arg = *arg;
+ if (unlikely(!ipi_arg))
+ goto ipi_mask_done;
+
+ ipi_arg->vector = vector;
+ ipi_arg->reserved = 0;
+ ipi_arg->cpu_mask = 0;
+
+ for_each_cpu(cur_cpu, mask) {
+ vcpu = hv_cpu_number_to_vp_number(cur_cpu);
+ /*
+ * This particular version of the IPI hypercall can
+ * only target upto 64 CPUs.
+ */
+ if (vcpu >= 64)
+ goto ipi_mask_done;
+
+ __set_bit(vcpu, (unsigned long *)&ipi_arg->cpu_mask);
+ }
+
+ ret = hv_do_hypercall(HVCALL_SEND_IPI, ipi_arg, NULL);
+
+ipi_mask_done:
+ local_irq_restore(flags);
+ return ((ret == 0) ? true : false);
+}
+
+static bool __send_ipi_one(int cpu, int vector)
+{
+ struct cpumask mask = CPU_MASK_NONE;
+
+ cpumask_set_cpu(cpu, &mask);
+ return __send_ipi_mask(&mask, vector);
+}
+
+static void hv_send_ipi(int cpu, int vector)
+{
+ if (!__send_ipi_one(cpu, vector))
+ orig_apic.send_IPI(cpu, vector);
+}
+
+static void hv_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+ if (!__send_ipi_mask(mask, vector))
+ orig_apic.send_IPI_mask(mask, vector);
+}
+
+static void hv_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+ unsigned int this_cpu = smp_processor_id();
+ struct cpumask new_mask;
+ const struct cpumask *local_mask;
+
+ cpumask_copy(&new_mask, mask);
+ cpumask_clear_cpu(this_cpu, &new_mask);
+ local_mask = &new_mask;
+ if (!__send_ipi_mask(local_mask, vector))
+ orig_apic.send_IPI_mask_allbutself(mask, vector);
+}
+
+static void hv_send_ipi_allbutself(int vector)
+{
+ hv_send_ipi_mask_allbutself(cpu_online_mask, vector);
+}
+
+static void hv_send_ipi_all(int vector)
+{
+ if (!__send_ipi_mask(cpu_online_mask, vector))
+ orig_apic.send_IPI_all(vector);
+}
+
+static void hv_send_ipi_self(int vector)
+{
+ if (!__send_ipi_one(smp_processor_id(), vector))
+ orig_apic.send_IPI_self(vector);
+}
+
void __init hv_apic_init(void)
{
+ if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
+ pr_info("Hyper-V: Using IPI hypercalls\n");
+ /*
+ * Set the IPI entry points.
+ */
+ orig_apic = *apic;
+
+ apic->send_IPI = hv_send_ipi;
+ apic->send_IPI_mask = hv_send_ipi_mask;
+ apic->send_IPI_mask_allbutself = hv_send_ipi_mask_allbutself;
+ apic->send_IPI_allbutself = hv_send_ipi_allbutself;
+ apic->send_IPI_all = hv_send_ipi_all;
+ apic->send_IPI_self = hv_send_ipi_self;
+ }
+
if (ms_hyperv.hints & HV_X64_APIC_ACCESS_RECOMMENDED) {
pr_info("Hyper-V: Using MSR based APIC access\n");
apic_set_eoi_write(hv_apic_eoi_write);