linux-kernel - [PATCH v3 5/7] drm/i915/gvt: subsitute kvm_read/write_guest with vfio_dma

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Message-Id: <20200224084805.31898-1-yan.y.zhao@intel.com>
Date:   Mon, 24 Feb 2020 03:48:05 -0500
From:   Yan Zhao <yan.y.zhao@...el.com>
To:     zhenyuw@...ux.intel.com
Cc:     alex.williamson@...hat.com, intel-gvt-dev@...ts.freedesktop.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        pbonzini@...hat.com, kevin.tian@...el.com, peterx@...hat.com,
        Yan Zhao <yan.y.zhao@...el.com>
Subject: [PATCH v3 5/7] 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@...el.com>
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index ed4c79cc3e09..3d6362fd94e7 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1979,33 +1979,13 @@ 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(info->vgpu->vdev.vfio_group, gpa, buf, len, write);
 }
 
 static int kvmgt_read_gpa(unsigned long handle, unsigned long gpa,
-- 
2.17.1