[PATCH v7 15/20] xen/riscv: create APLIC DT node for guest domains

Guests require a Device Tree description of the interrupt controller
topology. Add support for creating an APLIC node when building the
guest DT.

Provide stub for imsic_make_dt_node() it will be introduced properly
in follow-up patch.

The value chosen for GUEST_APLIC_S_BASE is based on QEMU one.

DT-building functions are marked __init because domain creation happens at
boot time, before the init sections are freed. In a typical deployment
libxl creates the interrupt controller node in userspace and hands the
complete FDT to Xen, so these functions are only called during early
domain construction.

Co-developed-by: Romain Caritey <[email protected]>
Signed-off-by: Oleksii Kurochko <[email protected]>
Acked-by: Jan Beulich <[email protected]>
---
Changes in v7:
 - Update the comment for guest_aplic_num_sources: drop "wired" to be less
   confusing, and mention that it is identical for every domain only for
   now.
 - Use ARRAY_SIZE() instead of sizeof() for the size argument of
   snprintf() in vaplic_make_domu_dt_node().
 - Add Acked-by: Jan Beulich <[email protected]>
---
Changes in v6:
 - Redefine GUEST_APLIC_MAX_SOURCES as 96U to avoid '+OU' in min(...).
 - s/guest_num_sources/guest_aplic_num_sources.
---
Changes in v5:
 - Drop pointless initializer for local variable res in
   vaplic_make_domu_dt_node().
 - Limit guest_num_sources in the similar way to IMSIC.
 - Rename VAPLIC_NUM_SOURCES to GUEST_APLIC_MAX_SOURCES to be aligned with
   the similar place in vIMSIC related code.
---
Changes in v4:
 - Drop spurious <xen/fdt-kernel.h> and <xen/libfdt/libfdt.h> includes from
   aplic.c (mistakenly added, they belong to vaplic.c).
 - Reduce vaplic_name[] from 128 to 32 bytes in vaplic_make_domu_dt_node().
 - Use __initconstrel (with const) for init_ops instead of __initdata.
 - s/__ULL/_UL for defintion of GUEST_APLIC_S_BASE.
---
Changes in v3:
 - Fix rebase conflicts becuase of this patch is reordered after IMSIC DT
   node creation is intoduced.
 - Update the commit message.
 - Move initialization of domaincfg with APLIC_DOMAINCFG_RO80 from this
   patch to earlier.
 - Change paddr_t aplic_size to unsigned int in vaplic_make_domu_dt_node()
   and replace the UB (after it started to be uint) aplic_size >> 32 with
   an explicit 0 in the DT reg property.
 - Add BUILD_BUG_ON() to be sure that aplic size isn't bigger then
   UINT32_MAX.
---
Changes in v2:
 - Avoid as max as possible of host properties inheritance. Only number of
   APLIC's irqs are checked what leads to an introduction of
   get_aplic_irqs_num().
 - Move this patch earlier what leads to an introduction of
   vimsic_make_domu_dt_node() stub.
 - s/vimsic_make_domu_dt_node/imsic_make_domu_dt_node.
 - Refactor vimsic_make_domu_dt_node() to avoid re-usage of APLIC host
   properties.
 - Drop next_phandle as it is now in common code.
 - Drop const for kinfo argument of vimsic_make_domu_dt_node() is is
   going to be updated inside vimsic_make_domu_dt_node().
 - Use introduced before vintc->num_irqs.
---
---
 xen/arch/riscv/aplic-priv.h               | 13 ++++
 xen/arch/riscv/aplic.c                    |  2 +
 xen/arch/riscv/include/asm/aplic.h        |  8 +++
 xen/arch/riscv/include/asm/guest-layout.h |  6 ++
 xen/arch/riscv/vaplic.c                   | 77 +++++++++++++++++++++++
 5 files changed, 106 insertions(+)

diff --git a/xen/arch/riscv/aplic-priv.h b/xen/arch/riscv/aplic-priv.h
index 85e0d028d1ae..35100d3a64fe 100644
--- a/xen/arch/riscv/aplic-priv.h
+++ b/xen/arch/riscv/aplic-priv.h
@@ -34,4 +34,17 @@ struct aplic_priv {
     const struct imsic_config *imsic_cfg;
 };
 
+/*
+ * Value is inspired by what QEMU is using for riscv,num-sources property for
+ * APLIC node.
+ */
+#define GUEST_APLIC_MAX_SOURCES 96U
+
+/*
+ * Specifies the number of interrupt sources supported by guest APLIC domain.
+ * Could be limited by host interrupt controller and is identical for every
+ * domain for now.
+ */
+extern unsigned int guest_aplic_num_sources;
+
 #endif /* ASM_RISCV_APLIC_PRIV_H */
diff --git a/xen/arch/riscv/aplic.c b/xen/arch/riscv/aplic.c
index d08401db46b3..c2d7183e1852 100644
--- a/xen/arch/riscv/aplic.c
+++ b/xen/arch/riscv/aplic.c
@@ -92,6 +92,8 @@ static int __init cf_check aplic_init(void)
         panic("%s: failed to get number of interrupt sources\n",
               node->full_name);
 
+    guest_aplic_num_sources = min(GUEST_APLIC_MAX_SOURCES, aplic_info.num_irqs);
+
     if ( aplic_info.num_irqs > ARRAY_SIZE(aplic.regs->sourcecfg) )
         aplic_info.num_irqs = ARRAY_SIZE(aplic.regs->sourcecfg);
 
diff --git a/xen/arch/riscv/include/asm/aplic.h b/xen/arch/riscv/include/asm/aplic.h
index 5a7fcb6ec4f1..07318aaac25d 100644
--- a/xen/arch/riscv/include/asm/aplic.h
+++ b/xen/arch/riscv/include/asm/aplic.h
@@ -34,6 +34,14 @@
 
 #define APLIC_TARGET_HART_IDX_SHIFT 18
 
+#define APLIC_IDC_SIZE          32
+
+#define APLIC_MIN_SIZE          0x4000
+#define APLIC_SIZE_ALIGN(x)     ROUNDUP(x, APLIC_MIN_SIZE)
+
+#define APLIC_SIZE(nr_cpus)     (APLIC_MIN_SIZE + \
+                                 APLIC_SIZE_ALIGN(APLIC_IDC_SIZE * (nr_cpus)))
+
 struct aplic_regs {
     uint32_t domaincfg;         /* 0x0000 */
     uint32_t sourcecfg[1023];   /* 0x0004 */
diff --git a/xen/arch/riscv/include/asm/guest-layout.h b/xen/arch/riscv/include/asm/guest-layout.h
index 5e566450bdfa..90603f06bb91 100644
--- a/xen/arch/riscv/include/asm/guest-layout.h
+++ b/xen/arch/riscv/include/asm/guest-layout.h
@@ -3,6 +3,12 @@
 
 #include <public/xen.h>
 
+/*
+ * Base address of the guest's supervisor-mode APLIC. The value is the address
+ * typically used for APLIC by QEMU.
+ */
+#define GUEST_APLIC_S_BASE _UL(0xd000000)
+
 /*
  * Base address of the guest's supervisor-mode IMSIC. The value is the address
  * typically used for IMSIC by QEMU.
diff --git a/xen/arch/riscv/vaplic.c b/xen/arch/riscv/vaplic.c
index c813979a2ecb..72bb2c4dc3c5 100644
--- a/xen/arch/riscv/vaplic.c
+++ b/xen/arch/riscv/vaplic.c
@@ -9,6 +9,8 @@
  */
 
 #include <xen/errno.h>
+#include <xen/fdt-kernel.h>
+#include <xen/libfdt/libfdt.h>
 #include <xen/sched.h>
 #include <xen/xvmalloc.h>
 
@@ -19,6 +21,12 @@
 
 #include "aplic-priv.h"
 
+unsigned int __ro_after_init guest_aplic_num_sources;
+
+#define VAPLIC_COMPATIBLE "riscv,aplic"
+
+#define FDT_VAPLIC_INT_CELLS 2
+
 static int cf_check vaplic_init(struct vcpu *v)
 {
     return vcpu_imsic_init(v);
@@ -29,6 +37,74 @@ static void cf_check vaplic_deinit(struct vcpu *v)
     return vcpu_imsic_deinit(v);
 }
 
+static int __init cf_check vaplic_make_domu_dt_node(struct kernel_info *kinfo)
+{
+    struct domain *d = kinfo->bd.d;
+    int res;
+    void *fdt = kinfo->fdt;
+    unsigned int msi_parent_phandle;
+    char vaplic_name[32];
+    unsigned int aplic_size = APLIC_SIZE(d->max_vcpus);
+    const __be32 reg[] = {
+        cpu_to_be32(GUEST_APLIC_S_BASE >> 32),
+        cpu_to_be32(GUEST_APLIC_S_BASE),
+        cpu_to_be32(0),
+        cpu_to_be32(aplic_size),
+    };
+
+    BUILD_BUG_ON(APLIC_SIZE(MAX_VIRT_CPUS) > UINT_MAX);
+
+    res = snprintf(vaplic_name, ARRAY_SIZE(vaplic_name), "/soc/aplic@%lx",
+                   GUEST_APLIC_S_BASE);
+    if ( res >= sizeof(vaplic_name) )
+    {
+        dprintk(XENLOG_DEBUG, "vaplic name is truncated\n");
+        return -ENOBUFS;
+    }
+
+    res = vimsic_make_domu_dt_node(kinfo, &msi_parent_phandle);
+    if ( res )
+        return res;
+
+    res = fdt_begin_node(fdt, vaplic_name);
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "#interrupt-cells", FDT_VAPLIC_INT_CELLS);
+    if ( res )
+        return res;
+
+    res = fdt_property(fdt, "reg", reg, sizeof(reg));
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "riscv,num-sources", guest_aplic_num_sources);
+    if ( res )
+        return res;
+
+    res = fdt_property(fdt, "interrupt-controller", NULL, 0);
+    if ( res )
+        return res;
+
+    res = fdt_property_string(fdt, "compatible", VAPLIC_COMPATIBLE);
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "msi-parent", msi_parent_phandle);
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "phandle", kinfo->phandle_intc);
+    if ( res )
+        return res;
+
+    return fdt_end_node(fdt);
+}
+
+static const struct vintc_init_ops __initconstrel init_ops = {
+    .make_domu_dt_node = vaplic_make_domu_dt_node,
+};
+
 static const struct vintc_ops vintc_ops = {
     .vcpu_init = vaplic_init,
     .vcpu_deinit = vaplic_deinit,
@@ -43,6 +119,7 @@ int domain_vaplic_init(struct domain *d)
 
     d->arch.vintc = &vaplic->vintc;
     d->arch.vintc->ops = &vintc_ops;
+    d->arch.vintc->init_ops = &init_ops;
 
     vaplic->regs.domaincfg = APLIC_DOMAINCFG_RO;
 
-- 
2.55.0