KVM: In-kernel string pio write support

Add string pio write support to support some version of Windows.

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

1 files changed, 37 insertions, 11 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index df9c05e9b34e..1be510b657fd 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1760,18 +1760,35 @@ static int complete_pio(struct kvm_vcpu *vcpu)
         return 0;
 }
 
-void kernel_pio(struct kvm_io_device *pio_dev, struct kvm_vcpu *vcpu)
+static void kernel_pio(struct kvm_io_device *pio_dev,
+                       struct kvm_vcpu *vcpu,
+                       void *pd)
 {
         /* 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);
+                                  pd);
         else
                 kvm_iodevice_write(pio_dev, vcpu->pio.port,
                                    vcpu->pio.size,
-                                   vcpu->pio_data);
+                                   pd);
+}
+
+static void pio_string_write(struct kvm_io_device *pio_dev,
+                             struct kvm_vcpu *vcpu)
+{
+        struct kvm_pio_request *io = &vcpu->pio;
+        void *pd = vcpu->pio_data;
+        int i;
+
+        for (i = 0; i < io->cur_count; i++) {
+                kvm_iodevice_write(pio_dev, io->port,
+                                   io->size,
+                                   pd);
+                pd += io->size;
+        }
 }
 
 int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
@@ -1779,7 +1796,7 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
                   gva_t address, int rep, unsigned port)
 {
         unsigned now, in_page;
-        int i;
+        int i, ret = 0;
         int nr_pages = 1;
         struct page *page;
         struct kvm_io_device *pio_dev;
@@ -1806,15 +1823,12 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
                 memcpy(vcpu->pio_data, &vcpu->regs[VCPU_REGS_RAX], 4);
                 kvm_arch_ops->decache_regs(vcpu);
                 if (pio_dev) {
-                        kernel_pio(pio_dev, vcpu);
+                        kernel_pio(pio_dev, vcpu, vcpu->pio_data);
                         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);
@@ -1862,9 +1876,21 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
                 }
         }
 
-        if (!vcpu->pio.in)
-                return pio_copy_data(vcpu);
-        return 0;
+        if (!vcpu->pio.in) {
+                /* string PIO write */
+                ret = pio_copy_data(vcpu);
+                if (ret >= 0 && pio_dev) {
+                        pio_string_write(pio_dev, vcpu);
+                        complete_pio(vcpu);
+                        if (vcpu->pio.count == 0)
+                                ret = 1;
+                }
+        } else if (pio_dev)
+                printk(KERN_ERR "no string pio read support yet, "
+                       "port %x size %d count %ld\n",
+                        port, size, count);
+
+        return ret;
 }
 EXPORT_SYMBOL_GPL(kvm_setup_pio);