[Xen-devel] [PATCH v7 19/32] xen/x86: allow disabling the emulated PIC

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Changes since v6:
 - Return ENODEV in vpic_load if the vpic is disabled.
 - Add asserts to vpic_irq_{negative/positive}_edge and vpic_ack_pending_irq
   to make sure they are not called when the vpic is disabled.
 - Add a check to vpic_reset in order to prevent calling it with the vpic
   disabled.

Changes since v4:
 - Add Andrew Cooper Acked-by.
---
 xen/arch/x86/hvm/vpic.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vpic.c b/xen/arch/x86/hvm/vpic.c
index 7c2edc8..6a2e87b 100644
--- a/xen/arch/x86/hvm/vpic.c
+++ b/xen/arch/x86/hvm/vpic.c
@@ -377,6 +377,9 @@ static int vpic_save(struct domain *d, hvm_domain_context_t 
*h)
     struct hvm_hw_vpic *s;
     int i;
 
+    if ( !has_vpic(d) )
+        return 0;
+
     /* Save the state of both PICs */
     for ( i = 0; i < 2 ; i++ )
     {
@@ -392,7 +395,10 @@ static int vpic_load(struct domain *d, 
hvm_domain_context_t *h)
 {
     struct hvm_hw_vpic *s;
     uint16_t inst;
-    
+
+    if ( !has_vpic(d) )
+        return -ENODEV;
+
     /* Which PIC is this? */
     inst = hvm_load_instance(h);
     if ( inst > 1 )
@@ -412,6 +418,9 @@ void vpic_reset(struct domain *d)
 {
     struct hvm_hw_vpic *vpic;
 
+    if ( !has_vpic(d) )
+        return;
+
     /* Master PIC. */
     vpic = &d->arch.hvm_domain.vpic[0];
     memset(vpic, 0, sizeof(*vpic));
@@ -425,6 +434,9 @@ void vpic_reset(struct domain *d)
 
 void vpic_init(struct domain *d)
 {
+    if ( !has_vpic(d) )
+        return;
+
     vpic_reset(d);
 
     register_portio_handler(d, 0x20, 2, vpic_intercept_pic_io);
@@ -439,6 +451,7 @@ void vpic_irq_positive_edge(struct domain *d, int irq)
     struct hvm_hw_vpic *vpic = &d->arch.hvm_domain.vpic[irq >> 3];
     uint8_t mask = 1 << (irq & 7);
 
+    ASSERT(has_vpic(d));
     ASSERT(irq <= 15);
     ASSERT(vpic_is_locked(vpic));
 
@@ -456,6 +469,7 @@ void vpic_irq_negative_edge(struct domain *d, int irq)
     struct hvm_hw_vpic *vpic = &d->arch.hvm_domain.vpic[irq >> 3];
     uint8_t mask = 1 << (irq & 7);
 
+    ASSERT(has_vpic(d));
     ASSERT(irq <= 15);
     ASSERT(vpic_is_locked(vpic));
 
@@ -473,6 +487,8 @@ int vpic_ack_pending_irq(struct vcpu *v)
     int irq, vector;
     struct hvm_hw_vpic *vpic = &v->domain->arch.hvm_domain.vpic[0];
 
+    ASSERT(has_vpic(v->domain));
+
     TRACE_2D(TRC_HVM_EMUL_PIC_PEND_IRQ_CALL, vlapic_accept_pic_intr(v),
              vpic->int_output);
     if ( !vlapic_accept_pic_intr(v) || !vpic->int_output )
-- 
1.9.5 (Apple Git-50.3)


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