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authorMichael Kelley <mikelley@microsoft.com>2021-03-02 13:38:18 -0800
committerWei Liu <wei.liu@kernel.org>2021-03-08 17:33:00 +0000
commitd608715d4771cf2d63de07a5d7b026b6f52a70a5 (patch)
tree73a567821ae3e494a4df3c3f08deffb6b3d8afdc /drivers/hv
parent946f4b8680b8ad177f6489e023a1d95e82d502e2 (diff)
Drivers: hv: vmbus: Move handling of VMbus interrupts
VMbus interrupts are most naturally modelled as per-cpu IRQs. But because x86/x64 doesn't have per-cpu IRQs, the core VMbus interrupt handling machinery is done in code under arch/x86 and Linux IRQs are not used. Adding support for ARM64 means adding equivalent code using per-cpu IRQs under arch/arm64. A better model is to treat per-cpu IRQs as the normal path (which it is for modern architectures), and the x86/x64 path as the exception. Do this by incorporating standard Linux per-cpu IRQ allocation into the main VMbus driver, and bypassing it in the x86/x64 exception case. For x86/x64, special case code is retained under arch/x86, but no VMbus interrupt handling code is needed under arch/arm64. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/1614721102-2241-7-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv')
-rw-r--r--drivers/hv/hv.c8
-rw-r--r--drivers/hv/vmbus_drv.c63
2 files changed, 63 insertions, 8 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index afe7a62b447f..917b29e873c5 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -16,6 +16,7 @@
#include <linux/version.h>
#include <linux/random.h>
#include <linux/clockchips.h>
+#include <linux/interrupt.h>
#include <clocksource/hyperv_timer.h>
#include <asm/mshyperv.h>
#include "hyperv_vmbus.h"
@@ -214,10 +215,12 @@ void hv_synic_enable_regs(unsigned int cpu)
hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
/* Setup the shared SINT. */
+ if (vmbus_irq != -1)
+ enable_percpu_irq(vmbus_irq, 0);
shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
VMBUS_MESSAGE_SINT);
- shared_sint.vector = hv_get_vector();
+ shared_sint.vector = vmbus_interrupt;
shared_sint.masked = false;
/*
@@ -285,6 +288,9 @@ void hv_synic_disable_regs(unsigned int cpu)
sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
sctrl.enable = 0;
hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
+
+ if (vmbus_irq != -1)
+ disable_percpu_irq(vmbus_irq);
}
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 7524d71a0f84..51c40d5e3c8a 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -48,8 +48,10 @@ static int hyperv_cpuhp_online;
static void *hv_panic_page;
+static long __percpu *vmbus_evt;
+
/* Values parsed from ACPI DSDT */
-static int vmbus_irq;
+int vmbus_irq;
int vmbus_interrupt;
/*
@@ -1381,7 +1383,13 @@ static void vmbus_isr(void)
tasklet_schedule(&hv_cpu->msg_dpc);
}
- add_interrupt_randomness(hv_get_vector(), 0);
+ add_interrupt_randomness(vmbus_interrupt, 0);
+}
+
+static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
+{
+ vmbus_isr();
+ return IRQ_HANDLED;
}
/*
@@ -1496,9 +1504,28 @@ static int vmbus_bus_init(void)
if (ret)
return ret;
- ret = hv_setup_vmbus_irq(vmbus_irq, vmbus_isr);
- if (ret)
- goto err_setup;
+ /*
+ * VMbus interrupts are best modeled as per-cpu interrupts. If
+ * on an architecture with support for per-cpu IRQs (e.g. ARM64),
+ * allocate a per-cpu IRQ using standard Linux kernel functionality.
+ * If not on such an architecture (e.g., x86/x64), then rely on
+ * code in the arch-specific portion of the code tree to connect
+ * the VMbus interrupt handler.
+ */
+
+ if (vmbus_irq == -1) {
+ hv_setup_vmbus_handler(vmbus_isr);
+ } else {
+ vmbus_evt = alloc_percpu(long);
+ ret = request_percpu_irq(vmbus_irq, vmbus_percpu_isr,
+ "Hyper-V VMbus", vmbus_evt);
+ if (ret) {
+ pr_err("Can't request Hyper-V VMbus IRQ %d, Err %d",
+ vmbus_irq, ret);
+ free_percpu(vmbus_evt);
+ goto err_setup;
+ }
+ }
ret = hv_synic_alloc();
if (ret)
@@ -1559,7 +1586,12 @@ err_connect:
err_cpuhp:
hv_synic_free();
err_alloc:
- hv_remove_vmbus_irq();
+ if (vmbus_irq == -1) {
+ hv_remove_vmbus_handler();
+ } else {
+ free_percpu_irq(vmbus_irq, vmbus_evt);
+ free_percpu(vmbus_evt);
+ }
err_setup:
bus_unregister(&hv_bus);
unregister_sysctl_table(hv_ctl_table_hdr);
@@ -2677,6 +2709,18 @@ static int __init hv_acpi_init(void)
ret = -ETIMEDOUT;
goto cleanup;
}
+
+ /*
+ * If we're on an architecture with a hardcoded hypervisor
+ * vector (i.e. x86/x64), override the VMbus interrupt found
+ * in the ACPI tables. Ensure vmbus_irq is not set since the
+ * normal Linux IRQ mechanism is not used in this case.
+ */
+#ifdef HYPERVISOR_CALLBACK_VECTOR
+ vmbus_interrupt = HYPERVISOR_CALLBACK_VECTOR;
+ vmbus_irq = -1;
+#endif
+
hv_debug_init();
ret = vmbus_bus_init();
@@ -2707,7 +2751,12 @@ static void __exit vmbus_exit(void)
vmbus_connection.conn_state = DISCONNECTED;
hv_stimer_global_cleanup();
vmbus_disconnect();
- hv_remove_vmbus_irq();
+ if (vmbus_irq == -1) {
+ hv_remove_vmbus_handler();
+ } else {
+ free_percpu_irq(vmbus_irq, vmbus_evt);
+ free_percpu(vmbus_evt);
+ }
for_each_online_cpu(cpu) {
struct hv_per_cpu_context *hv_cpu
= per_cpu_ptr(hv_context.cpu_context, cpu);