drm/i915/gvt: subsitute kvm_read/write_guest with vfio_dma_rw

As a device model, it is better to read/write guest memory using vfio
interface, so that vfio is able to maintain dirty info of device IOVAs.

Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200313031109.7989-1-yan.y.zhao@intel.com

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 811cee2..cee7376 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -2050,33 +2050,14 @@ static int kvmgt_rw_gpa(unsigned long handle, unsigned long gpa,
                        void *buf, unsigned long len, bool write)
 {
        struct kvmgt_guest_info *info;
-       struct kvm *kvm;
-       int idx, ret;
-       bool kthread = current->mm == NULL;
 
        if (!handle_valid(handle))
                return -ESRCH;
 
        info = (struct kvmgt_guest_info *)handle;
-       kvm = info->kvm;
-
-       if (kthread) {
-               if (!mmget_not_zero(kvm->mm))
-                       return -EFAULT;
-               use_mm(kvm->mm);
-       }
 
-       idx = srcu_read_lock(&kvm->srcu);
-       ret = write ? kvm_write_guest(kvm, gpa, buf, len) :
-                     kvm_read_guest(kvm, gpa, buf, len);
-       srcu_read_unlock(&kvm->srcu, idx);
-
-       if (kthread) {
-               unuse_mm(kvm->mm);
-               mmput(kvm->mm);
-       }
-
-       return ret;
+       return vfio_dma_rw(kvmgt_vdev(info->vgpu)->vfio_group,
+                          gpa, buf, len, write);
 }
 
 static int kvmgt_read_gpa(unsigned long handle, unsigned long gpa,