xen/dm: Introduce xendevicemodel_set_irq_level DM op

This patch adds ability to the device emulator to notify otherend
(some entity running in the guest) using a SPI and implements Arm
specific bits for it. Proposed interface allows emulator to set
the logical level of a one of a domain's IRQ lines.

We can't reuse the existing DM op (xen_dm_op_set_isa_irq_level)
to inject an interrupt as the "isa_irq" field is only 8-bit and
able to cover IRQ 0 - 255, whereas we need a wider range (0 - 1020).

Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

Message-Id: <1602780274-29141-19-git-send-email-olekstysh@gmail.com>

6 files changed, 96 insertions, 1 deletions

diff --git a/tools/libs/devicemodel/core.c b/tools/libs/devicemodel/core.c
index 4d4063956d..30bd79f8ba 100644
--- a/tools/libs/devicemodel/core.c
+++ b/tools/libs/devicemodel/core.c
@@ -430,6 +430,24 @@ int xendevicemodel_set_isa_irq_level(
     return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
 }
 
+int xendevicemodel_set_irq_level(
+    xendevicemodel_handle *dmod, domid_t domid, uint32_t irq,
+    unsigned int level)
+{
+    struct xen_dm_op op;
+    struct xen_dm_op_set_irq_level *data;
+
+    memset(&op, 0, sizeof(op));
+
+    op.op = XEN_DMOP_set_irq_level;
+    data = &op.u.set_irq_level;
+
+    data->irq = irq;
+    data->level = level;
+
+    return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
+}
+
 int xendevicemodel_set_pci_link_route(
     xendevicemodel_handle *dmod, domid_t domid, uint8_t link, uint8_t irq)
 {
diff --git a/tools/libs/devicemodel/include/xendevicemodel.h b/tools/libs/devicemodel/include/xendevicemodel.h
index e877f5c8a6..c06b3c84b9 100644
--- a/tools/libs/devicemodel/include/xendevicemodel.h
+++ b/tools/libs/devicemodel/include/xendevicemodel.h
@@ -209,6 +209,10 @@ int xendevicemodel_set_isa_irq_level(
     xendevicemodel_handle *dmod, domid_t domid, uint8_t irq,
     unsigned int level);
 
+int xendevicemodel_set_irq_level(
+    xendevicemodel_handle *dmod, domid_t domid, unsigned int irq,
+    unsigned int level);
+
 /**
  * This function maps a PCI INTx line to a an IRQ line.
  *
diff --git a/tools/libs/devicemodel/libxendevicemodel.map b/tools/libs/devicemodel/libxendevicemodel.map
index 561c62deb4..a0c30125de 100644
--- a/tools/libs/devicemodel/libxendevicemodel.map
+++ b/tools/libs/devicemodel/libxendevicemodel.map
@@ -32,6 +32,7 @@ VERS_1.2 {
 	global:
 		xendevicemodel_relocate_memory;
 		xendevicemodel_pin_memory_cacheattr;
+		xendevicemodel_set_irq_level;
 } VERS_1.1;
 
 VERS_1.3 {
diff --git a/xen/arch/arm/dm.c b/xen/arch/arm/dm.c
index 5d3da3769b..e4bb2339fa 100644
--- a/xen/arch/arm/dm.c
+++ b/xen/arch/arm/dm.c
@@ -17,10 +17,65 @@
 #include <xen/dm.h>
 #include <xen/hypercall.h>
 
+#include <asm/vgic.h>
+
 int arch_dm_op(struct xen_dm_op *op, struct domain *d,
                const struct dmop_args *op_args, bool *const_op)
 {
-    return -EOPNOTSUPP;
+    int rc;
+
+    switch ( op->op )
+    {
+    case XEN_DMOP_set_irq_level:
+    {
+        const struct xen_dm_op_set_irq_level *data =
+            &op->u.set_irq_level;
+        unsigned int i;
+
+        /* Only SPIs are supported */
+        if ( (data->irq < NR_LOCAL_IRQS) || (data->irq >= vgic_num_irqs(d)) )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        if ( data->level != 0 && data->level != 1 )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        /* Check that padding is always 0 */
+        for ( i = 0; i < sizeof(data->pad); i++ )
+        {
+            if ( data->pad[i] )
+            {
+                rc = -EINVAL;
+                break;
+            }
+        }
+
+        /*
+         * Allow to set the logical level of a line for non-allocated
+         * interrupts only.
+         */
+        if ( test_bit(data->irq, d->arch.vgic.allocated_irqs) )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        vgic_inject_irq(d, NULL, data->irq, data->level);
+        rc = 0;
+        break;
+    }
+
+    default:
+        rc = -EOPNOTSUPP;
+        break;
+    }
+
+    return rc;
 }
 
 /*
diff --git a/xen/common/dm.c b/xen/common/dm.c
index f3a8353048..5f23420c00 100644
--- a/xen/common/dm.c
+++ b/xen/common/dm.c
@@ -48,6 +48,7 @@ static int dm_op(const struct dmop_args *op_args)
         [XEN_DMOP_remote_shutdown]                  = sizeof(struct xen_dm_op_remote_shutdown),
         [XEN_DMOP_relocate_memory]                  = sizeof(struct xen_dm_op_relocate_memory),
         [XEN_DMOP_pin_memory_cacheattr]             = sizeof(struct xen_dm_op_pin_memory_cacheattr),
+        [XEN_DMOP_set_irq_level]                    = sizeof(struct xen_dm_op_set_irq_level),
     };
 
     rc = rcu_lock_remote_domain_by_id(op_args->domid, &d);
diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h
index 66cae1afbd..1f70d58caa 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -434,6 +434,21 @@ struct xen_dm_op_pin_memory_cacheattr {
 };
 typedef struct xen_dm_op_pin_memory_cacheattr xen_dm_op_pin_memory_cacheattr_t;
 
+/*
+ * XEN_DMOP_set_irq_level: Set the logical level of a one of a domain's
+ *                         IRQ lines (currently Arm only).
+ * Only SPIs are supported.
+ */
+#define XEN_DMOP_set_irq_level 19
+
+struct xen_dm_op_set_irq_level {
+    uint32_t irq;
+    /* IN - Level: 0 -> deasserted, 1 -> asserted */
+    uint8_t level;
+    uint8_t pad[3];
+};
+typedef struct xen_dm_op_set_irq_level xen_dm_op_set_irq_level_t;
+
 struct xen_dm_op {
     uint32_t op;
     uint32_t pad;
@@ -447,6 +462,7 @@ struct xen_dm_op {
         xen_dm_op_track_dirty_vram_t track_dirty_vram;
         xen_dm_op_set_pci_intx_level_t set_pci_intx_level;
         xen_dm_op_set_isa_irq_level_t set_isa_irq_level;
+        xen_dm_op_set_irq_level_t set_irq_level;
         xen_dm_op_set_pci_link_route_t set_pci_link_route;
         xen_dm_op_modified_memory_t modified_memory;
         xen_dm_op_set_mem_type_t set_mem_type;