[PATCH V1 12/16] xen/dm: Introduce xendevicemodel_set_irq_level DM op

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>

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.

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

---
Please note, this is a split/cleanup/hardening of Julien's PoC:
"Add support for Guest IO forwarding to a device emulator"

Please note, I left interface untouched since there is still
an open discussion what interface to use/what information to pass
to the hypervisor. The question whether we should abstract away
the state of the line or not.

Changes RFC -> V1:
   - check incoming parameters in arch_dm_op()
   - add explicit padding to struct xen_dm_op_set_irq_level
---
---
 tools/libs/devicemodel/core.c                   | 18 +++++++++++++
 tools/libs/devicemodel/include/xendevicemodel.h |  4 +++
 tools/libs/devicemodel/libxendevicemodel.map    |  1 +
 xen/arch/arm/dm.c                               | 36 ++++++++++++++++++++++++-
 xen/common/dm.c                                 |  1 +
 xen/include/public/hvm/dm_op.h                  | 15 +++++++++++
 6 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/tools/libs/devicemodel/core.c b/tools/libs/devicemodel/core.c
index 4d40639..30bd79f 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 e877f5c..c06b3c8 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 561c62d..a0c3012 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 eb20344..428ef98 100644
--- a/xen/arch/arm/dm.c
+++ b/xen/arch/arm/dm.c
@@ -15,11 +15,45 @@
  */
 
 #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;
+
+        /* 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;
+        }
+
+
+        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 060731d..c55e042 100644
--- a/xen/common/dm.c
+++ b/xen/common/dm.c
@@ -47,6 +47,7 @@ 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 fd00e9d..39567bf 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -417,6 +417,20 @@ struct xen_dm_op_pin_memory_cacheattr {
     uint32_t pad;
 };
 
+/*
+ * XEN_DMOP_set_irq_level: Set the logical level of a one of a domain's
+ *                         IRQ lines.
+ * XXX Handle PPIs.
+ */
+#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];
+};
+
 struct xen_dm_op {
     uint32_t op;
     uint32_t pad;
@@ -430,6 +444,7 @@ struct xen_dm_op {
         struct xen_dm_op_track_dirty_vram track_dirty_vram;
         struct xen_dm_op_set_pci_intx_level set_pci_intx_level;
         struct xen_dm_op_set_isa_irq_level set_isa_irq_level;
+        struct xen_dm_op_set_irq_level set_irq_level;
         struct xen_dm_op_set_pci_link_route set_pci_link_route;
         struct xen_dm_op_modified_memory modified_memory;
         struct xen_dm_op_set_mem_type set_mem_type;
-- 
2.7.4