[RFC][PATCH 09/10] xen/hybrid: Make event channel work with QEmu emulated devices
From: Sheng Yang
Date: Wed Sep 16 2009 - 04:44:55 EST
We mapped each IOAPIC pin to a VIRQ, so that we can deliver interrupt through
these VIRQs.
We also use GENERIC_INTERRUPT_VECTOR as the noficiation vector for hypervisor
to notify guest about the event.
Then we don't need IOAPIC/LAPIC now...
Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 14 ++++++++++++
arch/x86/xen/enlighten.c | 49 +++++++++++++++++++++++++++++++++++++++++++
arch/x86/xen/irq.c | 15 +++++++++++-
drivers/xen/events.c | 47 +++++++++++++++++++++++++++++++++++++++++
include/xen/events.h | 1 +
include/xen/hvm.h | 5 ++++
include/xen/interface/xen.h | 6 ++++-
7 files changed, 134 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 58d24ef..39c1890 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -67,6 +67,10 @@
#include <asm/smpboot_hooks.h>
+#ifdef CONFIG_XEN
+#include <asm/xen/hypervisor.h>
+#endif
+
#ifdef CONFIG_X86_32
u8 apicid_2_node[MAX_APICID];
static int low_mappings;
@@ -1062,6 +1066,11 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
}
set_cpu_sibling_map(0);
+#ifdef CONFIG_XEN
+ if (xen_hybrid_evtchn_enabled())
+ goto out;
+#endif
+
enable_IR_x2apic();
#ifdef CONFIG_X86_64
default_setup_apic_routing();
@@ -1131,6 +1140,11 @@ void __init native_smp_cpus_done(unsigned int max_cpus)
{
pr_debug("Boot done.\n");
+#ifdef CONFIG_XEN
+ if (xen_hybrid_evtchn_enabled())
+ return;
+#endif
+
impress_friends();
#ifdef CONFIG_X86_IO_APIC
setup_ioapic_dest();
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 18aba22..f515584 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -54,6 +54,10 @@
#include <asm/reboot.h>
#include <xen/hvm.h>
+#include <xen/events.h>
+#include <asm/acpi.h>
+#include <asm/irq_vectors.h>
+#include <asm/irq.h>
#include "xen-ops.h"
#include "mmu.h"
@@ -1055,6 +1059,8 @@ static void __init xen_hybrid_banner(void)
if (xen_hybrid_timer_enabled())
printk(KERN_INFO "Hybrid feature: PV Timer enabled\n");
+ if (xen_hybrid_evtchn_enabled())
+ printk(KERN_INFO "Hybrid feature: Event channel enabled\n");
}
static int xen_para_available(void)
@@ -1102,6 +1108,10 @@ static int init_hybrid_info(void)
xen_hybrid_status |= XEN_HYBRID_TIMER_ENABLED;
flags |= HVM_HYBRID_TIMER;
}
+ if (edx & XEN_CPUID_FEAT2_HYBRID_EVTCHN) {
+ xen_hybrid_status |= XEN_HYBRID_EVTCHN_ENABLED;
+ flags |= HVM_HYBRID_EVTCHN;
+ }
/* We only support 1 page of hypercall for now */
if (pages != 1)
@@ -1144,9 +1154,27 @@ static int __init init_shared_info(void)
return 0;
}
+static int set_callback_via(uint64_t via)
+{
+ struct xen_hvm_param a;
+
+ a.domid = DOMID_SELF;
+ a.index = HVM_PARAM_CALLBACK_IRQ;
+ a.value = via;
+ return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
+}
+
+void do_hybrid_intr(void)
+{
+ per_cpu(irq_count, smp_processor_id())++;
+ xen_evtchn_do_upcall(get_irq_regs());
+ per_cpu(irq_count, smp_processor_id())--;
+}
+
void __init xen_start_hybrid(void)
{
int r;
+ uint64_t callback_via;
if (!xen_para_available())
return;
@@ -1163,5 +1191,26 @@ void __init xen_start_hybrid(void)
pv_time_ops = xen_time_ops;
pv_apic_ops = xen_apic_ops;
}
+
+ if (xen_hybrid_evtchn_enabled()) {
+ pv_apic_ops = xen_apic_ops;
+#ifdef CONFIG_X86_LOCAL_APIC
+ /*
+ * set up the basic apic ops.
+ */
+ set_xen_basic_apic_ops();
+#endif
+
+ callback_via = HVM_CALLBACK_VECTOR(GENERIC_INTERRUPT_VECTOR);
+ set_callback_via(callback_via);
+
+ generic_interrupt_extension = do_hybrid_intr;
+
+ disable_acpi();
+ disable_apic = 1;
+
+ machine_ops = xen_machine_ops;
+ smp_ops.smp_send_stop = paravirt_nop;
+ }
}
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
index 52885c1..edca1c4 100644
--- a/arch/x86/xen/irq.c
+++ b/arch/x86/xen/irq.c
@@ -66,6 +66,9 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
static void xen_irq_disable(void)
{
+ if (xen_hybrid_evtchn_enabled())
+ asm volatile("cli" : : : "memory");
+
/* There's a one instruction preempt window here. We need to
make sure we're don't switch CPUs between getting the vcpu
pointer and updating the mask. */
@@ -79,6 +82,9 @@ static void xen_irq_enable(void)
{
struct vcpu_info *vcpu;
+ if (xen_hybrid_evtchn_enabled())
+ asm volatile("sti" : : : "memory");
+
/* We don't need to worry about being preempted here, since
either a) interrupts are disabled, so no preemption, or b)
the caller is confused and is trying to re-enable interrupts
@@ -137,6 +143,11 @@ void __init xen_init_irq_ops()
void __init xen_hybrid_init_irq_ops(void)
{
- pv_irq_ops.safe_halt = xen_safe_halt;
- pv_irq_ops.halt = xen_halt;
+ if (!xen_hybrid_evtchn_enabled()) {
+ pv_irq_ops.safe_halt = xen_safe_halt;
+ pv_irq_ops.halt = xen_halt;
+ } else {
+ pv_irq_ops = xen_irq_ops;
+ pv_irq_ops.adjust_exception_frame = paravirt_nop;
+ }
}
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 30963af..4973b70 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -40,6 +40,8 @@
#include <xen/interface/xen.h>
#include <xen/interface/event_channel.h>
+#include <asm/desc.h>
+
/*
* This lock protects updates to the following mapping and reference-count
* arrays. The lock does not need to be acquired to read the mapping tables.
@@ -931,4 +933,49 @@ void __init xen_init_IRQ(void)
mask_evtchn(i);
irq_ctx_init(smp_processor_id());
+
+ if (!xen_hybrid_evtchn_enabled())
+ return;
+
+ for (i = 0; i < NR_IRQS_LEGACY; i++) {
+ struct evtchn_bind_virq bind_virq;
+ struct irq_desc *desc = irq_to_desc(i);
+ int virq, evtchn;
+
+ virq = i + VIRQ_EMUL_PIN_START;
+ bind_virq.virq = virq;
+ bind_virq.vcpu = 0;
+
+ if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+ &bind_virq) != 0)
+ BUG();
+
+ evtchn = bind_virq.port;
+ evtchn_to_irq[evtchn] = i;
+ irq_info[i] = mk_virq_info(evtchn, virq);
+
+ desc->status = IRQ_DISABLED;
+ desc->action = NULL;
+ desc->depth = 1;
+
+ /*
+ * 16 old-style INTA-cycle interrupts:
+ */
+ set_irq_chip_and_handler_name(i, &xen_dynamic_chip,
+ handle_level_irq, "event");
+ }
+
+ /*
+ * Cover the whole vector space, no vector can escape
+ * us. (some of these will be overridden and become
+ * 'special' SMP interrupts)
+ */
+ for (i = 0; i < (NR_VECTORS - FIRST_EXTERNAL_VECTOR); i++) {
+ int vector = FIRST_EXTERNAL_VECTOR + i;
+ if (vector != IA32_SYSCALL_VECTOR)
+ set_intr_gate(vector, interrupt[i]);
+ }
+
+ /* generic IPI for platform specific use, now used for hybrid */
+ alloc_intr_gate(GENERIC_INTERRUPT_VECTOR, generic_interrupt);
}
diff --git a/include/xen/events.h b/include/xen/events.h
index 0d5f1ad..a21c68f 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -53,4 +53,5 @@ bool xen_test_irq_pending(int irq);
irq will be disabled so it won't deliver an interrupt. */
void xen_poll_irq(int irq);
+void xen_evtchn_do_upcall(struct pt_regs *regs);
#endif /* _XEN_EVENTS_H */
diff --git a/include/xen/hvm.h b/include/xen/hvm.h
index 4ea8887..c66d788 100644
--- a/include/xen/hvm.h
+++ b/include/xen/hvm.h
@@ -20,4 +20,9 @@ static inline unsigned long hvm_get_parameter(int idx)
return xhv.value;
}
+#define HVM_CALLBACK_VIA_TYPE_VECTOR 0x2
+#define HVM_CALLBACK_VIA_TYPE_SHIFT 56
+#define HVM_CALLBACK_VECTOR(x) (((uint64_t)HVM_CALLBACK_VIA_TYPE_VECTOR)<<\
+ HVM_CALLBACK_VIA_TYPE_SHIFT | (x))
+
#endif /* XEN_HVM_H__ */
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index 2befa3e..9282ff7 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -90,7 +90,11 @@
#define VIRQ_ARCH_6 22
#define VIRQ_ARCH_7 23
-#define NR_VIRQS 24
+#define VIRQ_EMUL_PIN_START 24
+#define VIRQ_EMUL_PIN_NUM 16
+
+#define NR_VIRQS 40
+
/*
* MMU-UPDATE REQUESTS
*
--
1.5.4.5
--
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