Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[mirror_ubuntu-eoan-kernel.git] / drivers / hv / hv.c

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 45f3694bbb76a4e5a175fc8e3fbf237c883a5c23..9b82549cbbc8e6937c02c289c7f5e5b5d1de2b79 100644 (file)
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -27,7 +27,7 @@
 #include <linux/vmalloc.h>
 #include <linux/hyperv.h>
 #include <linux/version.h>
-#include <linux/interrupt.h>
+#include <linux/random.h>
 #include <linux/clockchips.h>
 #include <asm/mshyperv.h>
 #include "hyperv_vmbus.h"
@@ -37,6 +37,17 @@ struct hv_context hv_context = {
        .synic_initialized      = false,
 };
 
+/*
+ * If false, we're using the old mechanism for stimer0 interrupts
+ * where it sends a VMbus message when it expires. The old
+ * mechanism is used when running on older versions of Hyper-V
+ * that don't support Direct Mode. While Hyper-V provides
+ * four stimer's per CPU, Linux uses only stimer0.
+ */
+static bool direct_mode_enabled;
+static int stimer0_irq;
+static int stimer0_vector;
+
 #define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
 #define HV_MAX_MAX_DELTA_TICKS 0xffffffff
 #define HV_MIN_DELTA_TICKS 1
@@ -52,6 +63,8 @@ int hv_init(void)
        if (!hv_context.cpu_context)
                return -ENOMEM;
 
+       direct_mode_enabled = ms_hyperv.misc_features &
+                       HV_X64_STIMER_DIRECT_MODE_AVAILABLE;
        return 0;
 }
 
@@ -90,6 +103,21 @@ int hv_post_message(union hv_connection_id connection_id,
        return status & 0xFFFF;
 }
 
+/*
+ * ISR for when stimer0 is operating in Direct Mode.  Direct Mode
+ * does not use VMbus or any VMbus messages, so process here and not
+ * in the VMbus driver code.
+ */
+
+static void hv_stimer0_isr(void)
+{
+       struct hv_per_cpu_context *hv_cpu;
+
+       hv_cpu = this_cpu_ptr(hv_context.cpu_context);
+       hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt);
+       add_interrupt_randomness(stimer0_vector, 0);
+}
+
 static int hv_ce_set_next_event(unsigned long delta,
                                struct clock_event_device *evt)
 {
@@ -107,6 +135,8 @@ static int hv_ce_shutdown(struct clock_event_device *evt)
 {
        hv_init_timer(HV_X64_MSR_STIMER0_COUNT, 0);
        hv_init_timer_config(HV_X64_MSR_STIMER0_CONFIG, 0);
+       if (direct_mode_enabled)
+               hv_disable_stimer0_percpu_irq(stimer0_irq);
 
        return 0;
 }
@@ -115,11 +145,26 @@ static int hv_ce_set_oneshot(struct clock_event_device *evt)
 {
        union hv_timer_config timer_cfg;
 
+       timer_cfg.as_uint64 = 0;
        timer_cfg.enable = 1;
        timer_cfg.auto_enable = 1;
-       timer_cfg.sintx = VMBUS_MESSAGE_SINT;
+       if (direct_mode_enabled) {
+               /*
+                * When it expires, the timer will directly interrupt
+                * on the specified hardware vector/IRQ.
+                */
+               timer_cfg.direct_mode = 1;
+               timer_cfg.apic_vector = stimer0_vector;
+               hv_enable_stimer0_percpu_irq(stimer0_irq);
+       } else {
+               /*
+                * When it expires, the timer will generate a VMbus message,
+                * to be handled by the normal VMbus interrupt handler.
+                */
+               timer_cfg.direct_mode = 0;
+               timer_cfg.sintx = VMBUS_MESSAGE_SINT;
+       }
        hv_init_timer_config(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
-
        return 0;
 }
 
@@ -146,7 +191,7 @@ int hv_synic_alloc(void)
        int cpu;
 
        hv_context.hv_numa_map = kzalloc(sizeof(struct cpumask) * nr_node_ids,
-                                        GFP_ATOMIC);
+                                        GFP_KERNEL);
        if (hv_context.hv_numa_map == NULL) {
                pr_err("Unable to allocate NUMA map\n");
                goto err;
@@ -190,6 +235,11 @@ int hv_synic_alloc(void)
                INIT_LIST_HEAD(&hv_cpu->chan_list);
        }
 
+       if (direct_mode_enabled &&
+           hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector,
+                               hv_stimer0_isr))
+               goto err;
+
        return 0;
 err:
        return -ENOMEM;
@@ -216,7 +266,7 @@ void hv_synic_free(void)
 }
 
 /*
- * hv_synic_init - Initialize the Synthethic Interrupt Controller.
+ * hv_synic_init - Initialize the Synthetic Interrupt Controller.
  *
  * If it is already initialized by another entity (ie x2v shim), we need to
  * retrieve the initialized message and event pages.  Otherwise, we create and
@@ -251,7 +301,6 @@ int hv_synic_init(unsigned int cpu)
        hv_get_synint_state(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT,
                            shared_sint.as_uint64);
 
-       shared_sint.as_uint64 = 0;
        shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
        shared_sint.masked = false;
        if (ms_hyperv.hints & HV_X64_DEPRECATING_AEOI_RECOMMENDED)
@@ -291,6 +340,9 @@ void hv_synic_clockevents_cleanup(void)
        if (!(ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE))
                return;
 
+       if (direct_mode_enabled)
+               hv_remove_stimer0_irq(stimer0_irq);
+
        for_each_present_cpu(cpu) {
                struct hv_per_cpu_context *hv_cpu
                        = per_cpu_ptr(hv_context.cpu_context, cpu);