[PATCH v2 17/26] xen/riscv: generate IMSIC DT node for guest domains

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Guests using the IMSIC interrupt controller require a corresponding
Device Tree description.

Add support for generating an IMSIC node when building the guest DT.
This allows guests to discover and use the IMSIC interrupt controller.

Co-developed-by: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
Changes in v2:
 - s/imsic_make_reg_property/guest_imsic_make_reg_property.
 - s/imsic_set_interrupt_extended_prop/guest_imsic_set_interrupt_extended_prop.
 - Use initalizer for regs[] array in imsic_make_reg_property().
 - Move buf[] insde the for() loop.
 - Correct check of returned phandle.
 - Drop local variable len.
 - /s/XVFREE/xvfree in imsic_set_interrupt_extended_prop().
 - Drop initializer for local variable data.
 - s/uint32_t/unsinged int for pos and cpu in 
imsic_set_interrupt_extended_prop().
 - Drop next_phandle as it is now in common code.
 - Introduce vcpu_imsic_deinit.
 - Refactor vimsic_make_domu_dt_node() to avoid usage of host IMSIC dt node.
---
 xen/arch/riscv/imsic.c                    | 127 +++++++++++++++++++++-
 xen/arch/riscv/include/asm/guest-layout.h |   2 +
 2 files changed, 128 insertions(+), 1 deletion(-)

diff --git a/xen/arch/riscv/imsic.c b/xen/arch/riscv/imsic.c
index ceea6778d9dc..19cbacdf96e1 100644
--- a/xen/arch/riscv/imsic.c
+++ b/xen/arch/riscv/imsic.c
@@ -13,9 +13,12 @@
 #include <xen/const.h>
 #include <xen/cpumask.h>
 #include <xen/device_tree.h>
+#include <xen/domain.h>
 #include <xen/errno.h>
+#include <xen/fdt-domain-build.h>
 #include <xen/fdt-kernel.h>
 #include <xen/init.h>
+#include <xen/libfdt/libfdt.h>
 #include <xen/macros.h>
 #include <xen/sched.h>
 #include <xen/smp.h>
@@ -35,6 +38,11 @@ static struct imsic_config imsic_cfg = {
     .lock = SPIN_LOCK_UNLOCKED,
 };
 
+static unsigned int __ro_after_init guest_num_msis;
+
+#define GUEST_IMSIC_COMPATIBLE "riscv,imsics"
+#define GUEST_IMSIC_NUM_MSIS 255
+
 #define IMSIC_DISABLE_EIDELIVERY    0
 #define IMSIC_ENABLE_EIDELIVERY     1
 #define IMSIC_DISABLE_EITHRESHOLD   1
@@ -291,6 +299,11 @@ static int imsic_parse_node(const struct dt_device_node 
*node,
         return -ENOENT;
     }
 
+    if ( dt_property_read_u32(node, "riscv,num-guest-ids", &tmp) )
+        guest_num_msis = tmp;
+    else
+        guest_num_msis = imsic_cfg.nr_ids;
+
     if ( (imsic_cfg.nr_ids < IMSIC_MIN_ID) ||
          (imsic_cfg.nr_ids > IMSIC_MAX_ID) )
     {
@@ -524,8 +537,120 @@ int __init imsic_init(const struct dt_device_node *node)
     return rc;
 }
 
+static int __init guest_imsic_make_reg_property(struct domain *d, void *fdt)
+{
+    paddr_t base_addr = GUEST_IMSIC_S_BASE;
+    __be32 regs[4] = {
+        cpu_to_be32(base_addr >> 32),
+        cpu_to_be32(base_addr),
+        cpu_to_be32((IMSIC_MMIO_PAGE_SZ * d->max_vcpus) >> 32),
+        cpu_to_be32(IMSIC_MMIO_PAGE_SZ * d->max_vcpus),
+    };
+
+    return fdt_property(fdt, "reg", regs, sizeof(regs));
+}
+
+static int __init guest_imsic_set_interrupt_extended_prop(struct domain *d,
+                                                          void *fdt)
+{
+    unsigned int cpu, pos = 0;
+    uint32_t phandle;
+    uint32_t *irq_ext;
+    int res;
+
+    irq_ext = xvzalloc_array(uint32_t, d->max_vcpus * 2);
+    if ( !irq_ext )
+        return -ENOMEM;
+
+    for ( cpu = 0; cpu < d->max_vcpus; cpu++ )
+    {
+        char buf[64];
+
+        snprintf(buf, sizeof(buf), "/cpus/cpu@%u/interrupt-controller", cpu);
+        phandle = fdt_get_phandle(fdt, fdt_path_offset(fdt, buf));
+
+        if ( !phandle )
+        {
+            res = -ENODEV;
+            goto out;
+        }
+
+        irq_ext[pos++] = cpu_to_be32(phandle);
+        irq_ext[pos++] = cpu_to_be32(IRQ_S_EXT);
+    }
+
+    res = fdt_property(fdt, "interrupts-extended", irq_ext,
+                       d->max_vcpus * 2 * sizeof(*irq_ext));
+
+ out:
+    xvfree(irq_ext);
+
+    return res;
+}
+
 int __init vimsic_make_domu_dt_node(struct kernel_info *kinfo,
                                     unsigned int *phandle)
 {
-    return -EOPNOTSUPP;
+    int res;
+    void *fdt = kinfo->fdt;
+    char vimsic_name[128];
+    unsigned int vimsic_phandle;
+    unsigned int num_msis = min(GUEST_IMSIC_NUM_MSIS + 0U, guest_num_msis);
+
+    res = snprintf(vimsic_name, sizeof(vimsic_name), "/soc/imsic@%x",
+                   GUEST_IMSIC_S_BASE);
+    if ( res >= sizeof(vimsic_name) )
+    {
+        dprintk(XENLOG_DEBUG, "vimsic name is truncated\n");
+        return -ENOBUFS;
+    }
+
+    res = fdt_begin_node(fdt, vimsic_name);
+    if ( res )
+        return res;
+
+    res = fdt_property_string(fdt, "compatible", GUEST_IMSIC_COMPATIBLE);
+    if ( res )
+        return res;
+
+    res = guest_imsic_make_reg_property(kinfo->bd.d, fdt);
+    if ( res )
+        return res;
+
+    res = guest_imsic_set_interrupt_extended_prop(kinfo->bd.d, fdt);
+    if ( res )
+        return res;
+
+    res = fdt_property_u32(fdt, "riscv,num-ids", num_msis);
+    if ( res )
+        return res;
+
+    res = fdt_property(fdt, "msi-controller", NULL, 0);
+    if ( res )
+        return res;
+
+    res = fdt_property_u32(fdt, "#msi-cells", 0);
+    if ( res )
+        return res;
+
+    res = fdt_property(fdt, "interrupt-controller", NULL, 0);
+    if ( res )
+        return res;
+
+    res = fdt_property_u32(fdt, "#interrupt-cells", 0);
+    if ( res )
+        return res;
+
+    vimsic_phandle = alloc_phandle(kinfo);
+    if ( !vimsic_phandle )
+        return -EOVERFLOW;
+
+    res = fdt_property_cell(fdt, "phandle", vimsic_phandle);
+    if ( res )
+        return res;
+
+    if ( phandle )
+        *phandle = vimsic_phandle;
+
+    return fdt_end_node(fdt);
 }
diff --git a/xen/arch/riscv/include/asm/guest-layout.h 
b/xen/arch/riscv/include/asm/guest-layout.h
index 9fc990c057f2..b16ec79c3786 100644
--- a/xen/arch/riscv/include/asm/guest-layout.h
+++ b/xen/arch/riscv/include/asm/guest-layout.h
@@ -5,6 +5,8 @@
 
 #define GUEST_APLIC_S_BASE 0xd000000
 
+#define GUEST_IMSIC_S_BASE 0x28000000
+
 #define GUEST_RAM_BANKS   2
 
 /*
-- 
2.54.0