[Xen-devel] [RFC PATCH v2 19/26] ARM: vITS: handle MAPTI command

[Andre Przywara <andre.przywara@xxxxxxx>]

The MAPTI commands associates a DeviceID/EventID pair with a LPI/CPU
pair and actually instantiates LPI interrupts.
We connect the already allocated host LPI to this virtual LPI, so that
any triggering IRQ on the host can be quickly forwarded to
a guest.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/gic-its.c        | 49 +++++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/vgic-its.c       | 44 ++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/gic-its.h |  4 ++++
 3 files changed, 97 insertions(+)

diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
index 54e604a..0acbd83 100644
--- a/xen/arch/arm/gic-its.c
+++ b/xen/arch/arm/gic-its.c
@@ -754,6 +754,55 @@ retry:
     return 0;
 }
 
+static union host_lpi *find_guest_lpi(struct domain *d,
+                                      uint32_t devid, uint32_t eventid)
+{
+    struct its_devices *dev;
+    uint32_t lpi;
+
+    list_for_each_entry( dev, &d->arch.vgic.its_devices, entry )
+    {
+        if (dev->guest_devid != devid )
+            continue;
+
+        if ( eventid >= dev->eventids )
+            return NULL;
+
+        lpi = dev->host_lpis[eventid / 32] + (eventid % 32);
+        if (lpi < 8192)
+            return NULL;
+
+        lpi -= 8192;
+
+        return &lpi_data.host_lpis[lpi / HOST_LPIS_PER_PAGE][lpi % 
HOST_LPIS_PER_PAGE];
+    }
+
+    return NULL;
+}
+
+/* Connects the event ID for an already assigned device to the given VCPU/vLPI
+ * pair. The corresponding physical LPI is already mapped on the host side
+ * (when assigning the physical device to the guest), so we just connect the
+ * target VCPU/vLPI pair to that interrupt to inject it properly if it fires.
+ */
+int gicv3_assign_guest_event(struct domain *d, uint32_t devid, uint32_t 
eventid,
+                             struct vcpu *v, uint32_t virt_lpi)
+{
+    union host_lpi hlpi, *hlpip;
+
+    hlpip = find_guest_lpi(d, devid, eventid);
+    if ( !hlpip )
+        return -1;
+
+    hlpi.virt_lpi = virt_lpi;
+    hlpi.dom_id = d->domain_id;
+    hlpi.vcpu_id = v->vcpu_id;
+
+    hlpip->data = hlpi.data;
+
+    return 0;
+}
+
 /* Scan the DT for any ITS nodes and create a list of host ITSes out of it. */
 void gicv3_its_dt_init(const struct dt_device_node *node)
 {
diff --git a/xen/arch/arm/vgic-its.c b/xen/arch/arm/vgic-its.c
index 918b504..f9f438a 100644
--- a/xen/arch/arm/vgic-its.c
+++ b/xen/arch/arm/vgic-its.c
@@ -276,6 +276,46 @@ static int its_handle_mapd(struct virt_its *its, uint64_t 
*cmdptr)
     return 0;
 }
 
+static int its_handle_mapti(struct virt_its *its, uint64_t *cmdptr)
+{
+    uint32_t devid = its_cmd_get_deviceid(cmdptr);
+    uint32_t eventid = its_cmd_get_id(cmdptr);
+    uint32_t intid = its_cmd_get_physical_id(cmdptr);
+    int collid = its_cmd_get_collection(cmdptr);
+    struct vits_itte *itte;
+    struct vcpu *vcpu;
+    int ret = -1;
+
+    if ( its_cmd_get_command(cmdptr) == GITS_CMD_MAPI )
+        intid = eventid;
+
+    if ( collid >= its->max_collections )
+        return -1;
+
+    spin_lock(&its->its_lock);
+    vcpu = get_vcpu_from_collection(its, collid);
+    if ( !vcpu )
+        goto out_unlock;
+
+    itte = get_devid_evid(its, devid, eventid);
+    if ( !itte )
+        goto out_unlock;
+
+    itte->vlpi = intid;
+    itte->collection = collid;
+
+    gicv3_assign_guest_event(its->d, devid, eventid, vcpu, intid);
+
+    ret = 0;
+
+    put_devid_evid(its, itte);
+
+out_unlock:
+    spin_unlock(&its->its_lock);
+    
+    return ret;
+}
+
 #define ITS_CMD_BUFFER_SIZE(baser)      ((((baser) & 0xff) + 1) << 12)
 
 static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its,
@@ -308,6 +348,10 @@ static int vgic_its_handle_cmds(struct domain *d, struct 
virt_its *its,
         case GITS_CMD_MAPD:
             its_handle_mapd(its, cmdptr);
            break;
+        case GITS_CMD_MAPI:
+        case GITS_CMD_MAPTI:
+            its_handle_mapti(its, cmdptr);
+            break;
         case GITS_CMD_SYNC:
             /* We handle ITS commands synchronously, so we ignore SYNC. */
            break;
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
index d1ebc19..9843674 100644
--- a/xen/include/asm-arm/gic-its.h
+++ b/xen/include/asm-arm/gic-its.h
@@ -137,6 +137,10 @@ void gicv3_its_setup_collection(int cpu);
 int gicv3_its_map_device(struct domain *d, int host_devid, int guest_devid,
                          int bits, bool valid);
 
+int gicv3_assign_guest_event(struct domain *d,
+                             uint32_t devid, uint32_t eventid,
+                             struct vcpu *v, uint32_t virt_lpi);
+
 #else
 
 static inline void gicv3_its_dt_init(const struct dt_device_node *node)
-- 
2.9.0


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