KVM: Add support for in-kernel pio handlers

Useful for the PIC and PIT.

Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

2 files changed, 37 insertions, 1 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 31846b1c162f..a7c5e6bee034 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -241,6 +241,7 @@ struct kvm_pio_request {
         struct page *guest_pages[2];
         unsigned guest_page_offset;
         int in;
+        int port;
         int size;
         int string;
         int down;
@@ -303,7 +304,8 @@ static inline int kvm_iodevice_inrange(struct kvm_io_device *dev, gpa_t addr)
 
 static inline void kvm_iodevice_destructor(struct kvm_io_device *dev)
 {
-        dev->destructor(dev);
+        if (dev->destructor)
+                dev->destructor(dev);
 }
 
 /*
@@ -453,6 +455,7 @@ struct kvm {
         struct list_head vm_list;
         struct file *filp;
         struct kvm_io_bus mmio_bus;
+        struct kvm_io_bus pio_bus;
 };
 
 struct descriptor_table {
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index e157e282fcff..7826f16271e5 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -361,6 +361,7 @@ static struct kvm *kvm_create_vm(void)
         if (!kvm)
                 return ERR_PTR(-ENOMEM);
 
+        kvm_io_bus_init(&kvm->pio_bus);
         spin_lock_init(&kvm->lock);
         INIT_LIST_HEAD(&kvm->active_mmu_pages);
         spin_lock(&kvm_lock);
@@ -475,6 +476,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
         spin_lock(&kvm_lock);
         list_del(&kvm->vm_list);
         spin_unlock(&kvm_lock);
+        kvm_io_bus_destroy(&kvm->pio_bus);
         kvm_io_bus_destroy(&kvm->mmio_bus);
         kvm_free_vcpus(kvm);
         kvm_free_physmem(kvm);
@@ -1110,6 +1112,12 @@ static struct kvm_io_device *vcpu_find_mmio_dev(struct kvm_vcpu *vcpu,
         return kvm_io_bus_find_dev(&vcpu->kvm->mmio_bus, addr);
 }
 
+static struct kvm_io_device *vcpu_find_pio_dev(struct kvm_vcpu *vcpu,
+                                               gpa_t addr)
+{
+        return kvm_io_bus_find_dev(&vcpu->kvm->pio_bus, addr);
+}
+
 static int emulator_read_emulated(unsigned long addr,
                                   void *val,
                                   unsigned int bytes,
@@ -1832,6 +1840,20 @@ static int complete_pio(struct kvm_vcpu *vcpu)
         return 0;
 }
 
+void kernel_pio(struct kvm_io_device *pio_dev, struct kvm_vcpu *vcpu)
+{
+        /* TODO: String I/O for in kernel device */
+
+        if (vcpu->pio.in)
+                kvm_iodevice_read(pio_dev, vcpu->pio.port,
+                                  vcpu->pio.size,
+                                  vcpu->pio_data);
+        else
+                kvm_iodevice_write(pio_dev, vcpu->pio.port,
+                                   vcpu->pio.size,
+                                   vcpu->pio_data);
+}
+
 int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
                   int size, unsigned long count, int string, int down,
                   gva_t address, int rep, unsigned port)
@@ -1840,6 +1862,7 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
         int i;
         int nr_pages = 1;
         struct page *page;
+        struct kvm_io_device *pio_dev;
 
         vcpu->run->exit_reason = KVM_EXIT_IO;
         vcpu->run->io.direction = in ? KVM_EXIT_IO_IN : KVM_EXIT_IO_OUT;
@@ -1851,17 +1874,27 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
         vcpu->pio.cur_count = count;
         vcpu->pio.size = size;
         vcpu->pio.in = in;
+        vcpu->pio.port = port;
         vcpu->pio.string = string;
         vcpu->pio.down = down;
         vcpu->pio.guest_page_offset = offset_in_page(address);
         vcpu->pio.rep = rep;
 
+        pio_dev = vcpu_find_pio_dev(vcpu, port);
         if (!string) {
                 kvm_arch_ops->cache_regs(vcpu);
                 memcpy(vcpu->pio_data, &vcpu->regs[VCPU_REGS_RAX], 4);
                 kvm_arch_ops->decache_regs(vcpu);
+                if (pio_dev) {
+                        kernel_pio(pio_dev, vcpu);
+                        complete_pio(vcpu);
+                        return 1;
+                }
                 return 0;
         }
+        /* TODO: String I/O for in kernel device */
+        if (pio_dev)
+                printk(KERN_ERR "kvm_setup_pio: no string io support\n");
 
         if (!count) {
                 kvm_arch_ops->skip_emulated_instruction(vcpu);