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, 20 insertions, 24 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2e0286596387..265a765f038f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -546,18 +546,27 @@ static inline struct kvm_lapic *to_lapic(struct kvm_io_device *dev)
         return container_of(dev, struct kvm_lapic, dev);
 }
 
-static void apic_mmio_read(struct kvm_io_device *this,
-                           gpa_t address, int len, void *data)
+static int apic_mmio_in_range(struct kvm_lapic *apic, gpa_t addr)
+{
+        return apic_hw_enabled(apic) &&
+            addr >= apic->base_address &&
+            addr < apic->base_address + LAPIC_MMIO_LENGTH;
+}
+
+static int apic_mmio_read(struct kvm_io_device *this,
+                          gpa_t address, int len, void *data)
 {
         struct kvm_lapic *apic = to_lapic(this);
         unsigned int offset = address - apic->base_address;
         unsigned char alignment = offset & 0xf;
         u32 result;
+        if (!apic_mmio_in_range(apic, address))
+                return -EOPNOTSUPP;
 
         if ((alignment + len) > 4) {
                 printk(KERN_ERR "KVM_APIC_READ: alignment error %lx %d",
                        (unsigned long)address, len);
-                return;
+                return 0;
         }
         result = __apic_read(apic, offset & ~0xf);
 
@@ -574,6 +583,7 @@ static void apic_mmio_read(struct kvm_io_device *this,
                        "should be 1,2, or 4 instead\n", len);
                 break;
         }
+        return 0;
 }
 
 static void update_divide_count(struct kvm_lapic *apic)
@@ -629,13 +639,15 @@ static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
                 apic->vcpu->kvm->arch.vapics_in_nmi_mode--;
 }
 
-static void apic_mmio_write(struct kvm_io_device *this,
-                            gpa_t address, int len, const void *data)
+static int apic_mmio_write(struct kvm_io_device *this,
+                           gpa_t address, int len, const void *data)
 {
         struct kvm_lapic *apic = to_lapic(this);
         unsigned int offset = address - apic->base_address;
         unsigned char alignment = offset & 0xf;
         u32 val;
+        if (!apic_mmio_in_range(apic, address))
+                return -EOPNOTSUPP;
 
         /*
          * APIC register must be aligned on 128-bits boundary.
@@ -646,7 +658,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
                 /* Don't shout loud, $infamous_os would cause only noise. */
                 apic_debug("apic write: bad size=%d %lx\n",
                            len, (long)address);
-                return;
+                return 0;
         }
 
         val = *(u32 *) data;
@@ -729,7 +741,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
                 hrtimer_cancel(&apic->lapic_timer.timer);
                 apic_set_reg(apic, APIC_TMICT, val);
                 start_apic_timer(apic);
-                return;
+                return 0;
 
         case APIC_TDCR:
                 if (val & 4)
@@ -743,22 +755,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
                            offset);
                 break;
         }
-
-}
-
-static int apic_mmio_range(struct kvm_io_device *this, gpa_t addr,
-                           int len, int size)
-{
-        struct kvm_lapic *apic = to_lapic(this);
-        int ret = 0;
-
-
-        if (apic_hw_enabled(apic) &&
-            (addr >= apic->base_address) &&
-            (addr < (apic->base_address + LAPIC_MMIO_LENGTH)))
-                ret = 1;
-
-        return ret;
+        return 0;
 }
 
 void kvm_free_lapic(struct kvm_vcpu *vcpu)
@@ -938,7 +935,6 @@ static struct kvm_timer_ops lapic_timer_ops = {
 static const struct kvm_io_device_ops apic_mmio_ops = {
         .read     = apic_mmio_read,
         .write    = apic_mmio_write,
-        .in_range = apic_mmio_range,
 };
 
 int kvm_create_lapic(struct kvm_vcpu *vcpu)