[Xen-devel] [PATCH v9 01/28] ARM: GICv3: setup number of LPI bits for a GICv3 guest

[Andre Przywara <andre.przywara@xxxxxxx>]

The host supports a certain number of LPI identifiers, as stored in
the GICD_TYPER register.
Store this number from the hardware register in vgic_v3_hw to allow
injecting the very same number into a guest (Dom0).
DomUs get a fixed limited number for now. We may want to revisit this
when we get proper DomU ITS support.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
 xen/arch/arm/gic-v3.c         | 6 +++++-
 xen/arch/arm/vgic-v3.c        | 9 ++++++++-
 xen/include/asm-arm/domain.h  | 1 +
 xen/include/asm-arm/vgic.h    | 3 ++-
 xen/include/public/arch-arm.h | 4 ++++
 5 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index a559e5e..29c8964 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1579,6 +1579,7 @@ static int __init gicv3_init(void)
 {
     int res, i;
     uint32_t reg;
+    unsigned int intid_bits;
 
     if ( !cpu_has_gicv3 )
     {
@@ -1622,8 +1623,11 @@ static int __init gicv3_init(void)
                i, r->base, r->base + r->size);
     }
 
+    reg = readl_relaxed(GICD + GICD_TYPER);
+    intid_bits = GICD_TYPE_ID_BITS(reg);
+
     vgic_v3_setup_hw(dbase, gicv3.rdist_count, gicv3.rdist_regions,
-                     gicv3.rdist_stride);
+                     gicv3.rdist_stride, intid_bits);
     gicv3_init_v2();
 
     spin_lock_init(&gicv3.lock);
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index d10757a..25e16dc 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -57,18 +57,21 @@ static struct {
     unsigned int nr_rdist_regions;
     const struct rdist_region *regions;
     uint32_t rdist_stride; /* Re-distributor stride */
+    unsigned int intid_bits;  /* Number of interrupt ID bits */
 } vgic_v3_hw;
 
 void vgic_v3_setup_hw(paddr_t dbase,
                       unsigned int nr_rdist_regions,
                       const struct rdist_region *regions,
-                      uint32_t rdist_stride)
+                      uint32_t rdist_stride,
+                      unsigned int intid_bits)
 {
     vgic_v3_hw.enabled = 1;
     vgic_v3_hw.dbase = dbase;
     vgic_v3_hw.nr_rdist_regions = nr_rdist_regions;
     vgic_v3_hw.regions = regions;
     vgic_v3_hw.rdist_stride = rdist_stride;
+    vgic_v3_hw.intid_bits = intid_bits;
 }
 
 static struct vcpu *vgic_v3_irouter_to_vcpu(struct domain *d, uint64_t irouter)
@@ -1482,6 +1485,8 @@ static int vgic_v3_domain_init(struct domain *d)
 
             first_cpu += size / d->arch.vgic.rdist_stride;
         }
+
+        d->arch.vgic.intid_bits = vgic_v3_hw.intid_bits;
     }
     else
     {
@@ -1497,6 +1502,8 @@ static int vgic_v3_domain_init(struct domain *d)
         d->arch.vgic.rdist_regions[0].base = GUEST_GICV3_GICR0_BASE;
         d->arch.vgic.rdist_regions[0].size = GUEST_GICV3_GICR0_SIZE;
         d->arch.vgic.rdist_regions[0].first_cpu = 0;
+
+        d->arch.vgic.intid_bits = GUEST_GICV3_GICD_INTID_BITS;
     }
 
     ret = vgic_v3_its_init_domain(d);
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 6de8082..7c3829d 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -111,6 +111,7 @@ struct arch_domain
         uint32_t rdist_stride;              /* Re-Distributor stride */
         struct rb_root its_devices;         /* Devices mapped to an ITS */
         spinlock_t its_devices_lock;        /* Protects the its_devices tree */
+        unsigned int intid_bits;
 #endif
     } vgic;
 
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 544867a..df75064 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -346,7 +346,8 @@ struct rdist_region;
 void vgic_v3_setup_hw(paddr_t dbase,
                       unsigned int nr_rdist_regions,
                       const struct rdist_region *regions,
-                      uint32_t rdist_stride);
+                      uint32_t rdist_stride,
+                      unsigned int intid_bits);
 #endif
 
 #endif /* __ASM_ARM_VGIC_H__ */
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index bd974fb..033dcee 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -400,6 +400,10 @@ typedef uint64_t xen_callback_t;
 #define GUEST_GICV3_GICD_BASE      xen_mk_ullong(0x03001000)
 #define GUEST_GICV3_GICD_SIZE      xen_mk_ullong(0x00010000)
 
+/* TODO: Should this number be a tool stack decision? */
+/* The number of interrupt ID bits a guest (not Dom0) sees. */
+#define GUEST_GICV3_GICD_INTID_BITS     16
+
 #define GUEST_GICV3_RDIST_STRIDE   xen_mk_ullong(0x00020000)
 #define GUEST_GICV3_RDIST_REGIONS  1
 
-- 
2.9.0


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