[Xen-devel] [RFC PATCH 07/24] ARM: GICv3 ITS: introduce device mapping

[Andre Przywara <andre.przywara@xxxxxxx>]

The ITS uses device IDs to map LPIs to a device. Dom0 will later use
those IDs, which we directly pass on to the host.
For this we have to map each device that Dom0 may request to a host
ITS device with the same identifier.
Allocate the respective memory and enter each device into a list to
later be able to iterate over it or to easily teardown guests.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/gic-its.c        | 90 +++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/gic-its.h | 16 ++++++++
 2 files changed, 106 insertions(+)

diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
index 2140e4a..bf1f5b5 100644
--- a/xen/arch/arm/gic-its.c
+++ b/xen/arch/arm/gic-its.c
@@ -168,6 +168,94 @@ static int its_send_cmd_mapc(struct host_its *its, int 
collection_id, int cpu)
     return its_send_command(its, cmd);
 }
 
+static int its_send_cmd_mapd(struct host_its *its, uint32_t deviceid,
+                             int size, uint64_t itt_addr, bool valid)
+{
+    uint64_t cmd[4];
+
+    cmd[0] = GITS_CMD_MAPD | ((uint64_t)deviceid << 32);
+    cmd[1] = size & GENMASK(4, 0);
+    cmd[2] = itt_addr & GENMASK(51, 8);
+    if ( valid )
+        cmd[2] |= BIT(63);
+    cmd[3] = 0x00;
+
+    return its_send_command(its, cmd);
+}
+
+int gicv3_its_map_device(struct host_its *hw_its, struct domain *d,
+                         int devid, int bits, bool valid)
+{
+    void *itt_addr = NULL;
+    struct its_devices *dev, *temp;
+    bool reuse_dev = false;
+
+    list_for_each_entry_safe(dev, temp, &hw_its->its_devices, entry)
+    {
+        if ( (dev->d->domain_id != d->domain_id) || (dev->devid != devid) )
+            continue;
+
+        its_send_cmd_mapd(hw_its, dev->devid, 0, 0, false);
+        xfree(dev->itt_addr);
+        if ( !valid )
+        {
+            xfree(dev);
+            list_del(&dev->entry);
+
+            return 0;
+        }
+
+        reuse_dev = true;
+        break;
+    }
+
+    if ( !valid )
+        return 0;
+
+    itt_addr = _xmalloc(BIT(bits) * hw_its->itte_size, 256);
+    if ( !itt_addr )
+        return -ENOMEM;
+
+    if ( !reuse_dev )
+    {
+        dev = xmalloc(struct its_devices);
+        if ( !dev )
+            return -ENOMEM;
+
+        list_add_tail(&dev->entry, &hw_its->its_devices);
+    }
+
+    dev->itt_addr = itt_addr;
+    dev->d = d;
+    dev->devid = devid;
+
+    return its_send_cmd_mapd(hw_its, devid, bits - 1,
+                             itt_addr ? virt_to_maddr(itt_addr) : 0, true);
+}
+
+/* Removing any connections a domain had to any ITS in the system. */
+int its_remove_domain(struct domain *d)
+{
+    struct host_its *its;
+    struct its_devices *dev, *temp;
+
+    list_for_each_entry(its, &host_its_list, entry)
+    {
+        list_for_each_entry_safe(dev, temp, &its->its_devices, entry)
+        {
+            if ( dev->d->domain_id != d->domain_id )
+                continue;
+
+            its_send_cmd_mapd(its, dev->devid, 0, 0, false);
+            xfree(dev->itt_addr);
+            xfree(dev);
+            list_del(&dev->entry);
+        }
+    }
+
+    return 0;
+}
+
 /* Set up the (1:1) collection mapping for the given host CPU. */
 void gicv3_its_setup_collection(int cpu)
 {
@@ -297,6 +385,7 @@ int gicv3_its_init(struct host_its *hw_its)
 
     reg = readq_relaxed(hw_its->its_base + GITS_TYPER);
     hw_its->pta = reg & GITS_TYPER_PTA;
+    hw_its->itte_size = ((reg >> 4) & 0xf) + 1;
 
     for (i = 0; i < 8; i++)
     {
@@ -520,6 +609,7 @@ void gicv3_its_dt_init(const struct dt_device_node *node)
         its_data->size = size;
         its_data->dt_node = its;
         spin_lock_init(&its_data->cmd_lock);
+        INIT_LIST_HEAD(&its_data->its_devices);
 
         printk("GICv3: Found ITS @0x%lx\n", addr);
 
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
index 512a388..4e9841a 100644
--- a/xen/include/asm-arm/gic-its.h
+++ b/xen/include/asm-arm/gic-its.h
@@ -79,6 +79,13 @@
 #ifndef __ASSEMBLY__
 #include <xen/device_tree.h>
 
+struct its_devices {
+    struct list_head entry;
+    struct domain *d;
+    void *itt_addr;
+    int devid;
+};
+
 /* data structure for each hardware ITS */
 struct host_its {
     struct list_head entry;
@@ -88,6 +95,8 @@ struct host_its {
     void __iomem *its_base;
     spinlock_t cmd_lock;
     void *cmd_buf;
+    struct list_head its_devices;
+    int itte_size;
     bool pta;
 };
 
@@ -114,6 +123,13 @@ void gicv3_set_redist_addr(paddr_t address, int redist_id);
 /* Map a collection for this host CPU to each host ITS. */
 void gicv3_its_setup_collection(int cpu);
 
+/* Map a device on the host by allocating an ITT on the host (ITS).
+ * "bits" specifies how many events (interrupts) this device will need.
+ * Setting "valid" to false deallocates the device.
+ */
+int gicv3_its_map_device(struct host_its *hw_its, struct domain *d,
+                         int devid, int bits, bool valid);
+
 int gicv3_lpi_allocate_host_lpi(struct host_its *its,
                                 uint32_t devid, uint32_t eventid,
                                 struct vcpu *v, int virt_lpi);
-- 
2.9.0


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