[PATCH v2 1/4] xen/arm: trap guest WFI

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Trap guest WFI, block the guest VCPU unless it has pending interrupts.
Awake the guest vcpu when a new interrupt for it arrrives.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 xen/arch/arm/domain_build.c |    2 +-
 xen/arch/arm/traps.c        |    7 +++++++
 xen/arch/arm/vgic.c         |    4 +++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 1e9776d..aa0f191 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -331,7 +331,7 @@ int construct_dom0(struct domain *d)
 
     WRITE_CP32(SCTLR_BASE, SCTLR);
 
-    WRITE_CP32(HCR_PTW|HCR_BSU_OUTER|HCR_AMO|HCR_IMO|HCR_VM, HCR);
+    WRITE_CP32(HCR_PTW|HCR_BSU_OUTER|HCR_AMO|HCR_IMO|HCR_VM|HCR_TWI, HCR);
     isb();
 
     local_abort_enable();
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 5347dce..b313e7a 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -29,6 +29,7 @@
 #include <xen/hypercall.h>
 #include <xen/softirq.h>
 #include <xen/domain_page.h>
+#include <public/sched.h>
 #include <public/xen.h>
 #include <asm/regs.h>
 #include <asm/cpregs.h>
@@ -781,6 +782,12 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs *regs)
     case HSR_EC_DATA_ABORT_GUEST:
         do_trap_data_abort_guest(regs, hsr.dabt);
         break;
+    /* at the moment we only trap WFI */
+    case HSR_EC_WFI_WFE:
+        if ( list_empty(&current->arch.vgic.inflight_irqs) )
+            do_sched_op_compat(SCHEDOP_block, 0);
+        regs->pc += hsr.len ? 4 : 2;
+        break;
     default:
         printk("Hypervisor Trap. HSR=0x%x EC=0x%x IL=%x Syndrome=%"PRIx32"\n",
                hsr.bits, hsr.ec, hsr.len, hsr.iss);
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 39b9775..8495384 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -608,12 +608,14 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq, int virtual)
         {
             list_add_tail(&n->inflight, &iter->inflight);
             spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
-            return;
+            goto out;
         }
     }
     list_add_tail(&n->inflight, &v->arch.vgic.inflight_irqs);
     spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
     /* we have a new higher priority irq, inject it into the guest */
+out:
+    vcpu_unblock(v);
 }
 
 /*
-- 
1.7.2.5