[v3,04/11] x86/vmsi: use the newly introduced EOI callbacks

Commit Message

Roger Pau Monne March 31, 2021, 10:32 a.m. UTC

Remove the unconditional call to hvm_dpci_msi_eoi in vlapic_handle_EOI
and instead use the newly introduced EOI callback mechanism in order
to register a callback for MSI vectors injected from passed through
devices.

This avoids having multiple callback functions open-coded in
vlapic_handle_EOI, as there is now a generic framework for registering
such callbacks. It also avoids doing an unconditional call to
hvm_dpci_msi_eoi for each EOI processed by the local APIC.

Note that now the callback is only registered (and thus executed) when
there's an MSI interrupt originating from a PCI passthrough device
being injected into the guest, so the check in hvm_dpci_msi_eoi can be
removed as it's already done by hvm_dirq_assist which is the only
caller of vmsi_deliver_pirq.

Signed-off-by: Roger Pau Monné <[e-mail]>
---
Changes since v2:
 - Expand commit message.
 - Pass the domain as the callback data.
 - Remove the check in hvm_dpci_msi_eoi
---
 xen/arch/x86/hvm/vlapic.c         |  2 --
 xen/arch/x86/hvm/vmsi.c           | 35 ++++++++++++++++++-------------
 xen/drivers/passthrough/x86/hvm.c |  8 ++-----
 xen/include/asm-x86/hvm/io.h      |  2 +-
 4 files changed, 24 insertions(+), 23 deletions(-)

Comments

Jan Beulich April 7, 2021, 2:59 p.m. UTC | #1

On 31.03.2021 12:32, Roger Pau Monne wrote:
> Remove the unconditional call to hvm_dpci_msi_eoi in vlapic_handle_EOI
> and instead use the newly introduced EOI callback mechanism in order
> to register a callback for MSI vectors injected from passed through
> devices.
> 
> This avoids having multiple callback functions open-coded in
> vlapic_handle_EOI, as there is now a generic framework for registering
> such callbacks. It also avoids doing an unconditional call to
> hvm_dpci_msi_eoi for each EOI processed by the local APIC.
> 
> Note that now the callback is only registered (and thus executed) when
> there's an MSI interrupt originating from a PCI passthrough device
> being injected into the guest, so the check in hvm_dpci_msi_eoi can be
> removed as it's already done by hvm_dirq_assist which is the only
> caller of vmsi_deliver_pirq.
> 
> Signed-off-by: Roger Pau Monné <[e-mail]>

Reviewed-by: Jan Beulich <[e-mail]>

Patch

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 851a1f5bd6c..10b216345a7 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -499,8 +499,6 @@  void vlapic_handle_EOI(struct vlapic *vlapic, u8 vector)
     if ( vlapic_test_vector(vector, &vlapic->regs->data[APIC_TMR]) )
         vioapic_update_EOI(vector);
 
-    hvm_dpci_msi_eoi(vector);
-
     spin_lock_irqsave(&vlapic->callback_lock, flags);
     callback = vlapic->callbacks[index].callback;
     vlapic->callbacks[index].callback = NULL;
diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
index 13e2a190b43..3da0a2261fd 100644
--- a/xen/arch/x86/hvm/vmsi.c
+++ b/xen/arch/x86/hvm/vmsi.c
@@ -44,11 +44,9 @@ 
 #include <asm/event.h>
 #include <asm/io_apic.h>
 
-static void vmsi_inj_irq(
-    struct vlapic *target,
-    uint8_t vector,
-    uint8_t trig_mode,
-    uint8_t delivery_mode)
+static void vmsi_inj_irq(struct vlapic *target, uint8_t vector,
+                         uint8_t trig_mode, uint8_t delivery_mode,
+                         vlapic_eoi_callback_t *callback, void *data)
 {
     HVM_DBG_LOG(DBG_LEVEL_VLAPIC, "vmsi_inj_irq: vec %02x trig %d dm %d\n",
                 vector, trig_mode, delivery_mode);
@@ -57,17 +55,17 @@  static void vmsi_inj_irq(
     {
     case dest_Fixed:
     case dest_LowestPrio:
-        vlapic_set_irq(target, vector, trig_mode);
+        vlapic_set_irq_callback(target, vector, trig_mode, callback, data);
         break;
     default:
         BUG();
     }
 }
 
-int vmsi_deliver(
-    struct domain *d, int vector,
-    uint8_t dest, uint8_t dest_mode,
-    uint8_t delivery_mode, uint8_t trig_mode)
+static int vmsi_deliver_callback(struct domain *d, int vector, uint8_t dest,
+                                 uint8_t dest_mode, uint8_t delivery_mode,
+                                 uint8_t trig_mode,
+                                 vlapic_eoi_callback_t *callback, void *data)
 {
     struct vlapic *target;
     struct vcpu *v;
@@ -78,7 +76,8 @@  int vmsi_deliver(
         target = vlapic_lowest_prio(d, NULL, 0, dest, dest_mode);
         if ( target != NULL )
         {
-            vmsi_inj_irq(target, vector, trig_mode, delivery_mode);
+            vmsi_inj_irq(target, vector, trig_mode, delivery_mode, callback,
+                         data);
             break;
         }
         HVM_DBG_LOG(DBG_LEVEL_VLAPIC, "null MSI round robin: vector=%02x\n",
@@ -89,8 +88,8 @@  int vmsi_deliver(
         for_each_vcpu ( d, v )
             if ( vlapic_match_dest(vcpu_vlapic(v), NULL,
                                    0, dest, dest_mode) )
-                vmsi_inj_irq(vcpu_vlapic(v), vector,
-                             trig_mode, delivery_mode);
+                vmsi_inj_irq(vcpu_vlapic(v), vector, trig_mode, delivery_mode,
+                             callback, data);
         break;
 
     default:
@@ -103,6 +102,13 @@  int vmsi_deliver(
     return 0;
 }
 
+int vmsi_deliver(struct domain *d, int vector, uint8_t dest, uint8_t dest_mode,
+                 uint8_t delivery_mode, uint8_t trig_mode)
+{
+    return vmsi_deliver_callback(d, vector, dest, dest_mode, delivery_mode,
+                                 trig_mode, NULL, NULL);
+}
+
 void vmsi_deliver_pirq(struct domain *d, const struct hvm_pirq_dpci *pirq_dpci)
 {
     uint32_t flags = pirq_dpci->gmsi.gflags;
@@ -119,7 +125,8 @@  void vmsi_deliver_pirq(struct domain *d, const struct hvm_pirq_dpci *pirq_dpci)
 
     ASSERT(pirq_dpci->flags & HVM_IRQ_DPCI_GUEST_MSI);
 
-    vmsi_deliver(d, vector, dest, dest_mode, delivery_mode, trig_mode);
+    vmsi_deliver_callback(d, vector, dest, dest_mode, delivery_mode, trig_mode,
+                          hvm_dpci_msi_eoi, d);
 }
 
 /* Return value, -1 : multi-dests, non-negative value: dest_vcpu_id */
diff --git a/xen/drivers/passthrough/x86/hvm.c b/xen/drivers/passthrough/x86/hvm.c
index a9256e7ef51..2331af896d4 100644
--- a/xen/drivers/passthrough/x86/hvm.c
+++ b/xen/drivers/passthrough/x86/hvm.c
@@ -796,13 +796,9 @@  static int _hvm_dpci_msi_eoi(struct domain *d,
     return 0;
 }
 
-void hvm_dpci_msi_eoi(unsigned int vector)
+void hvm_dpci_msi_eoi(unsigned int vector, void *data)
 {
-    struct domain *d = current->domain;
-
-    if ( !is_iommu_enabled(d) ||
-         (!hvm_domain_irq(d)->dpci && !is_hardware_domain(d)) )
-       return;
+    struct domain *d = data;
 
     spin_lock(&d->event_lock);
     pt_pirq_iterate(d, _hvm_dpci_msi_eoi, (void *)(long)vector);
diff --git a/xen/include/asm-x86/hvm/io.h b/xen/include/asm-x86/hvm/io.h
index 4f294232fb7..9ac3e4f48f6 100644
--- a/xen/include/asm-x86/hvm/io.h
+++ b/xen/include/asm-x86/hvm/io.h
@@ -142,7 +142,7 @@  struct hvm_hw_stdvga {
 void stdvga_init(struct domain *d);
 void stdvga_deinit(struct domain *d);
 
-extern void hvm_dpci_msi_eoi(unsigned int vector);
+void hvm_dpci_msi_eoi(unsigned int vector, void *data);
 
 /* Decode a PCI port IO access into a bus/slot/func/reg. */
 unsigned int hvm_pci_decode_addr(unsigned int cf8, unsigned int addr,