[PATCH v2 5/6] Nested VMX: Update APIC-v(RVI/SVI) when vmexit to L1

[Yang Zhang <yang.z.zhang@intel.com>]

From: Yang Zhang <yang.z.zhang@Intel.com>

If enabling APIC-v, all interrupts to L1 are delivered through APIC-v.
But when L2 is running, external interrupt will casue L1 vmexit with
reason external interrupt. Then L1 will pick up the interrupt through
vmcs12. when L1 ack the interrupt, since the APIC-v is enabled when
L1 is running, so APIC-v hardware still will do vEOI updating. The problem
is that the interrupt is delivered not through APIC-v hardware, this means
SVI/RVI/vPPR are not setting, but hardware required them when doing vEOI
updating. The solution is that, when L1 tried to pick up the interrupt
from vmcs12, then hypervisor will help to update the SVI/RVI/vPPR to make
sure the following vEOI updating and vPPR updating corrently.

Also, since interrupt is delivered through vmcs12, so APIC-v hardware will
not cleare vIRR and hypervisor need to clear it before L1 running.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
---
 xen/arch/x86/hvm/irq.c           |    2 +-
 xen/arch/x86/hvm/vlapic.c        |   12 ++++++------
 xen/arch/x86/hvm/vmx/vvmx.c      |   33 +++++++++++++++++++++++++++++++++
 xen/include/asm-x86/hvm/vlapic.h |    2 +-
 4 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c
index 9eae5de..6a6fb68 100644
--- a/xen/arch/x86/hvm/irq.c
+++ b/xen/arch/x86/hvm/irq.c
@@ -437,7 +437,7 @@ struct hvm_intack hvm_vcpu_ack_pending_irq(
             intack.vector = (uint8_t)vector;
         break;
     case hvm_intsrc_lapic:
-        if ( !vlapic_ack_pending_irq(v, intack.vector) )
+        if ( !vlapic_ack_pending_irq(v, intack.vector, 0) )
             intack = hvm_intack_none;
         break;
     case hvm_intsrc_vector:
diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 99c5700..d21a6c9 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -1058,15 +1058,15 @@ int vlapic_has_pending_irq(struct vcpu *v)
     return irr;
 }
 
-int vlapic_ack_pending_irq(struct vcpu *v, int vector)
+int vlapic_ack_pending_irq(struct vcpu *v, int vector, int force_ack)
 {
     struct vlapic *vlapic = vcpu_vlapic(v);
 
-    if ( vlapic_virtual_intr_delivery_enabled() )
-        return 1;
-
-    vlapic_set_vector(vector, &vlapic->regs->data[APIC_ISR]);
-    vlapic_clear_irr(vector, vlapic);
+    if ( force_ack || !vlapic_virtual_intr_delivery_enabled() )
+    {
+        vlapic_set_vector(vector, &vlapic->regs->data[APIC_ISR]);
+        vlapic_clear_irr(vector, vlapic);
+    }
 
     return 1;
 }
diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 5dfbc54..c197ad5 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1283,6 +1283,36 @@ static void sync_exception_state(struct vcpu *v)
     }
 }
 
+static void nvmx_update_apicv(struct vcpu *v)
+{
+    struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
+    struct nestedvcpu *nvcpu = &vcpu_nestedhvm(v);
+    unsigned long reason = __get_vvmcs(nvcpu->nv_vvmcx, VM_EXIT_REASON);
+    uint32_t intr_info = __get_vvmcs(nvcpu->nv_vvmcx, VM_EXIT_INTR_INFO);
+
+    if ( reason == EXIT_REASON_EXTERNAL_INTERRUPT &&
+         nvmx->intr.source == hvm_intsrc_lapic &&
+         (intr_info & INTR_INFO_VALID_MASK) )
+    {
+        uint16_t status;
+        uint32_t rvi, ppr;
+        uint32_t vector = intr_info & 0xff;
+        struct vlapic *vlapic = vcpu_vlapic(v);
+        
+        vlapic_ack_pending_irq(v, vector, 1);
+
+        ppr = vlapic_set_ppr(vlapic);
+        WARN_ON( (ppr & 0xf0) != (vector & 0xf0) );
+
+        status = vector << 8;
+        rvi = vlapic_has_pending_irq(v);
+        if ( rvi != -1 )
+            status |= rvi & 0xff;
+
+        __vmwrite(GUEST_INTR_STATUS, status);
+    }
+}
+
 static void virtual_vmexit(struct cpu_user_regs *regs)
 {
     struct vcpu *v = current;
@@ -1328,6 +1358,9 @@ static void virtual_vmexit(struct cpu_user_regs *regs)
     /* updating host cr0 to sync TS bit */
     __vmwrite(HOST_CR0, v->arch.hvm_vmx.host_cr0);
 
+    if ( cpu_has_vmx_virtual_intr_delivery )
+        nvmx_update_apicv(v);
+
     vmreturn(regs, VMSUCCEED);
 }
 
diff --git a/xen/include/asm-x86/hvm/vlapic.h b/xen/include/asm-x86/hvm/vlapic.h
index 29ba7d9..6109137 100644
--- a/xen/include/asm-x86/hvm/vlapic.h
+++ b/xen/include/asm-x86/hvm/vlapic.h
@@ -96,7 +96,7 @@ bool_t is_vlapic_lvtpc_enabled(struct vlapic *vlapic);
 void vlapic_set_irq(struct vlapic *vlapic, uint8_t vec, uint8_t trig);
 
 int vlapic_has_pending_irq(struct vcpu *v);
-int vlapic_ack_pending_irq(struct vcpu *v, int vector);
+int vlapic_ack_pending_irq(struct vcpu *v, int vector, int force_ack);
 
 int  vlapic_init(struct vcpu *v);
 void vlapic_destroy(struct vcpu *v);
-- 
1.7.1