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[Xen-devel] [RFC PATCH v2 06/26] ARM: GICv3 ITS: introduce device mapping



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        | 118 ++++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/vgic.c           |   3 ++
 xen/include/asm-arm/domain.h  |   2 +
 xen/include/asm-arm/gic-its.h |  22 ++++++++
 4 files changed, 145 insertions(+)

diff --git a/xen/arch/arm/gic-its.c b/xen/arch/arm/gic-its.c
index d0f5fd1..e157c6b 100644
--- a/xen/arch/arm/gic-its.c
+++ b/xen/arch/arm/gic-its.c
@@ -21,6 +21,7 @@
 #include <xen/err.h>
 #include <xen/device_tree.h>
 #include <xen/libfdt/libfdt.h>
+#include <xen/sched.h>
 #include <xen/sizes.h>
 #include <asm/p2m.h>
 #include <asm/io.h>
@@ -108,6 +109,21 @@ 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_ULL(63);
+    cmd[3] = 0x00;
+
+    return its_send_command(its, cmd);
+}
+
 /* Set up the (1:1) collection mapping for the given host CPU. */
 void gicv3_its_setup_collection(int cpu)
 {
@@ -237,6 +253,7 @@ 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 < GITS_BASER_NR_REGS; i++ )
     {
@@ -358,6 +375,107 @@ int gicv3_lpi_init_host_lpis(unsigned int hw_lpi_bits)
     return 0;
 }
 
+static void remove_mapped_guest_device(struct its_devices *dev)
+{
+    if ( dev->hw_its )
+        its_send_cmd_mapd(dev->hw_its, dev->host_devid, 0, 0, false);
+
+    xfree(dev->itt_addr);
+    xfree(dev);
+}
+
+int gicv3_its_map_device(struct domain *d, int host_devid, int guest_devid,
+                         int bits, bool valid)
+{
+    void *itt_addr = NULL;
+    struct its_devices *dev, *temp;
+    struct host_its *hw_its;
+    int ret;
+
+    /* check for already existing mappings */
+    spin_lock(&d->arch.vgic.its_devices_lock);
+    list_for_each_entry_safe(dev, temp, &d->arch.vgic.its_devices, entry)
+    {
+        if ( dev->guest_devid != guest_devid )
+            continue;
+
+        if ( !valid )
+            list_del(&dev->entry);
+
+        spin_unlock(&d->arch.vgic.its_devices_lock);
+
+        if ( valid )
+            return -EBUSY;
+
+        remove_mapped_guest_device(dev);
+
+        return 0;
+    }
+    spin_unlock(&d->arch.vgic.its_devices_lock);
+
+    if ( !valid )
+        return -ENOENT;
+
+    /* TODO: Work out the correct hardware ITS to use here.
+     * Maybe a per-platform function: devid -> ITS?
+     * Or parsing the DT to find the msi_parent?
+     * Or get Dom0 to give us this information?
+     * For now just use the first ITS.
+     */
+    hw_its = list_first_entry(&host_its_list, struct host_its, entry);
+
+    itt_addr = _xmalloc(BIT(bits) * hw_its->itte_size, 256);
+    if ( !itt_addr )
+        return -ENOMEM;
+
+    dev = xmalloc(struct its_devices);
+    if ( !dev )
+    {
+        xfree(itt_addr);
+        return -ENOMEM;
+    }
+
+    ret = its_send_cmd_mapd(hw_its, host_devid, bits - 1,
+                            virt_to_maddr(itt_addr), true);
+    if (ret) {
+        xfree(itt_addr);
+        xfree(dev);
+        return ret;
+    }
+
+    dev->itt_addr = itt_addr;
+    dev->hw_its = hw_its;
+    dev->guest_devid = guest_devid;
+    dev->host_devid = host_devid;
+    dev->eventids = BIT(bits);
+
+    spin_lock(&d->arch.vgic.its_devices_lock);
+    list_add_tail(&dev->entry, &d->arch.vgic.its_devices);
+    spin_unlock(&d->arch.vgic.its_devices_lock);
+
+    return 0;
+}
+
+/* Removing any connections a domain had to any ITS in the system. */
+int its_remove_domain(struct domain *d)
+{
+    struct its_devices *dev, *temp;
+
+retry:
+
+    spin_lock(&d->arch.vgic.its_devices_lock);
+    list_for_each_entry_safe(dev, temp, &d->arch.vgic.its_devices, entry)
+    {
+        list_del(&dev->entry);
+        spin_unlock(&d->arch.vgic.its_devices_lock);
+
+        remove_mapped_guest_device(dev);
+        goto retry;
+    }
+
+    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.c b/xen/arch/arm/vgic.c
index 364d5f0..de77aaa 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -156,6 +156,9 @@ int domain_vgic_init(struct domain *d, unsigned int nr_spis)
     for ( i = 0; i < NR_GIC_SGI; i++ )
         set_bit(i, d->arch.vgic.allocated_irqs);
 
+    spin_lock_init(&d->arch.vgic.its_devices_lock);
+    INIT_LIST_HEAD(&d->arch.vgic.its_devices);
+
     return 0;
 }
 
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 2d6fbb1..8ccc32a 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -109,6 +109,8 @@ struct arch_domain
         } *rdist_regions;
         int nr_regions;                     /* Number of rdist regions */
         uint32_t rdist_stride;              /* Re-Distributor stride */
+        struct list_head its_devices;       /* devices mapped to an ITS */
+        spinlock_t its_devices_lock;        /* protects the its_devices list */
 #endif
     } vgic;
 
diff --git a/xen/include/asm-arm/gic-its.h b/xen/include/asm-arm/gic-its.h
index 68e5f63..525a29d 100644
--- a/xen/include/asm-arm/gic-its.h
+++ b/xen/include/asm-arm/gic-its.h
@@ -93,9 +93,19 @@ struct host_its {
     void __iomem *its_base;
     spinlock_t cmd_lock;
     void *cmd_buf;
+    int itte_size;
     bool pta;
 };
 
+struct its_devices {
+    struct list_head entry;
+    struct host_its *hw_its;
+    void *itt_addr;
+    uint32_t guest_devid;
+    uint32_t host_devid;
+    uint32_t eventids;
+};
+
 extern struct list_head host_its_list;
 
 #ifdef CONFIG_HAS_ITS
@@ -119,6 +129,13 @@ 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 domain *d, int host_devid, int guest_devid,
+                         int bits, bool valid);
+
 #else
 
 static inline void gicv3_its_dt_init(const struct dt_device_node *node)
@@ -146,6 +163,11 @@ static inline void gicv3_set_redist_addr(paddr_t address, 
int redist_id)
 static inline void gicv3_its_setup_collection(int cpu)
 {
 }
+static inline int gicv3_its_map_device(struct domain *d, int host_devid,
+                         int guest_devid, int bits, bool valid)
+{
+    return -ENODEV;
+}
 
 #endif /* CONFIG_HAS_ITS */
 
-- 
2.9.0


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