KVM: remove in_range from io devices

This changes bus accesses to use high-level kvm_io_bus_read/kvm_io_bus_write
functions. in_range now becomes unused so it is removed from device ops in
favor of read/write callbacks performing range checks internally.

This allows aliasing (mostly for in-kernel virtio), as well as better error
handling by making it possible to pass errors up to userspace.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 12 insertions, 10 deletions

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 0eca54e06326..ddf6aa998b18 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -227,20 +227,19 @@ static inline struct kvm_ioapic *to_ioapic(struct kvm_io_device *dev)
         return container_of(dev, struct kvm_ioapic, dev);
 }
 
-static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr,
-                           int len, int is_write)
+static inline int ioapic_in_range(struct kvm_ioapic *ioapic, gpa_t addr)
 {
-        struct kvm_ioapic *ioapic = to_ioapic(this);
-
         return ((addr >= ioapic->base_address &&
                  (addr < ioapic->base_address + IOAPIC_MEM_LENGTH)));
 }
 
-static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
-                             void *val)
+static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
+                            void *val)
 {
         struct kvm_ioapic *ioapic = to_ioapic(this);
         u32 result;
+        if (!ioapic_in_range(ioapic, addr))
+                return -EOPNOTSUPP;
 
         ioapic_debug("addr %lx\n", (unsigned long)addr);
         ASSERT(!(addr & 0xf));  /* check alignment */
@@ -273,13 +272,16 @@ static void ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len,
                 printk(KERN_WARNING "ioapic: wrong length %d\n", len);
         }
         mutex_unlock(&ioapic->kvm->irq_lock);
+        return 0;
 }
 
-static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
-                              const void *val)
+static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
+                             const void *val)
 {
         struct kvm_ioapic *ioapic = to_ioapic(this);
         u32 data;
+        if (!ioapic_in_range(ioapic, addr))
+                return -EOPNOTSUPP;
 
         ioapic_debug("ioapic_mmio_write addr=%p len=%d val=%p\n",
                      (void*)addr, len, val);
@@ -290,7 +292,7 @@ static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
                 data = *(u32 *) val;
         else {
                 printk(KERN_WARNING "ioapic: Unsupported size %d\n", len);
-                return;
+                return 0;
         }
 
         addr &= 0xff;
@@ -312,6 +314,7 @@ static void ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len,
                 break;
         }
         mutex_unlock(&ioapic->kvm->irq_lock);
+        return 0;
 }
 
 void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
@@ -329,7 +332,6 @@ void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
 static const struct kvm_io_device_ops ioapic_mmio_ops = {
         .read     = ioapic_mmio_read,
         .write    = ioapic_mmio_write,
-        .in_range = ioapic_in_range,
 };
 
 int kvm_ioapic_init(struct kvm *kvm)