[Xen-devel] [PATCH 41/57] ARM: new VGIC: Add CONFIG registers handlers

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

The config register handlers are shared between the v2 and v3 emulation,
so their implementation goes into vgic-mmio.c, to be easily referenced
from the v3 emulation as well later.

This is based on Linux commit 79717e4ac09c, written by Andre Przywara.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
---
Changelog RFC ... v1:
- use C99 data types

 xen/arch/arm/vgic/vgic-mmio-v2.c |  2 +-
 xen/arch/arm/vgic/vgic-mmio.c    | 54 ++++++++++++++++++++++++++++++++++++++++
 xen/arch/arm/vgic/vgic-mmio.h    |  7 ++++++
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/vgic/vgic-mmio-v2.c b/xen/arch/arm/vgic/vgic-mmio-v2.c
index 29db9dec6f..d19ddd3f1e 100644
--- a/xen/arch/arm/vgic/vgic-mmio-v2.c
+++ b/xen/arch/arm/vgic/vgic-mmio-v2.c
@@ -104,7 +104,7 @@ static const struct vgic_register_region 
vgic_v2_dist_registers[] = {
         vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
         VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
     REGISTER_DESC_WITH_BITS_PER_IRQ(GICD_ICFGR,
-        vgic_mmio_read_raz, vgic_mmio_write_wi, 2,
+        vgic_mmio_read_config, vgic_mmio_write_config, 2,
         VGIC_ACCESS_32bit),
     REGISTER_DESC_WITH_LENGTH(GICD_SGIR,
         vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
diff --git a/xen/arch/arm/vgic/vgic-mmio.c b/xen/arch/arm/vgic/vgic-mmio.c
index 538f08bc66..31f7cf706b 100644
--- a/xen/arch/arm/vgic/vgic-mmio.c
+++ b/xen/arch/arm/vgic/vgic-mmio.c
@@ -431,6 +431,60 @@ void vgic_mmio_write_priority(struct vcpu *vcpu,
     }
 }
 
+unsigned long vgic_mmio_read_config(struct vcpu *vcpu,
+                                    paddr_t addr, unsigned int len)
+{
+    uint32_t intid = VGIC_ADDR_TO_INTID(addr, 2);
+    uint32_t value = 0;
+    int i;
+
+    for ( i = 0; i < len * 4; i++ )
+    {
+        struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
+
+        if ( irq->config == VGIC_CONFIG_EDGE )
+            value |= (2U << (i * 2));
+
+        vgic_put_irq(vcpu->domain, irq);
+    }
+
+    return value;
+}
+
+void vgic_mmio_write_config(struct vcpu *vcpu,
+                            paddr_t addr, unsigned int len,
+                            unsigned long val)
+{
+    uint32_t intid = VGIC_ADDR_TO_INTID(addr, 2);
+    int i;
+    unsigned long flags;
+
+    for ( i = 0; i < len * 4; i++ )
+    {
+        struct vgic_irq *irq;
+
+        /*
+         * The configuration cannot be changed for SGIs in general,
+         * for PPIs this is IMPLEMENTATION DEFINED. The arch timer
+         * code relies on PPIs being level triggered, so we also
+         * make them read-only here.
+         */
+        if ( intid + i < VGIC_NR_PRIVATE_IRQS )
+            continue;
+
+        irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
+        spin_lock_irqsave(&irq->irq_lock, flags);
+
+        if ( test_bit(i * 2 + 1, &val) )
+            irq->config = VGIC_CONFIG_EDGE;
+        else
+            irq->config = VGIC_CONFIG_LEVEL;
+
+        spin_unlock_irqrestore(&irq->irq_lock, flags);
+        vgic_put_irq(vcpu->domain, irq);
+    }
+}
+
 static int match_region(const void *key, const void *elt)
 {
     const unsigned int offset = (unsigned long)key;
diff --git a/xen/arch/arm/vgic/vgic-mmio.h b/xen/arch/arm/vgic/vgic-mmio.h
index e3f9029344..bbf0d181ae 100644
--- a/xen/arch/arm/vgic/vgic-mmio.h
+++ b/xen/arch/arm/vgic/vgic-mmio.h
@@ -136,6 +136,13 @@ void vgic_mmio_write_priority(struct vcpu *vcpu,
                   paddr_t addr, unsigned int len,
                   unsigned long val);
 
+unsigned long vgic_mmio_read_config(struct vcpu *vcpu,
+                    paddr_t addr, unsigned int len);
+
+void vgic_mmio_write_config(struct vcpu *vcpu,
+                paddr_t addr, unsigned int len,
+                unsigned long val);
+
 unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
 
 #endif
-- 
2.14.1


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