From 776d95b768e664efdc9f5cc078b981a006d3bff4 Mon Sep 17 00:00:00 2001 From: Yan Zhao Date: Thu, 12 Mar 2020 23:10:25 -0400 Subject: [PATCH 1/3] drm/i915/gvt: hold reference of VFIO group during opening of vgpu hold reference count of the VFIO group for each vgpu at vgpu opening and release the reference at vgpu releasing. Signed-off-by: Yan Zhao Reviewed-by: Zhenyu Wang Signed-off-by: Zhenyu Wang Link: http://patchwork.freedesktop.org/patch/msgid/20200313031025.7936-1-yan.y.zhao@intel.com --- drivers/gpu/drm/i915/gvt/kvmgt.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 074c4efb58eb9..811cee28ae06a 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -131,6 +131,7 @@ struct kvmgt_vdev { struct work_struct release_work; atomic_t released; struct vfio_device *vfio_device; + struct vfio_group *vfio_group; }; static inline struct kvmgt_vdev *kvmgt_vdev(struct intel_vgpu *vgpu) @@ -792,6 +793,7 @@ static int intel_vgpu_open(struct mdev_device *mdev) struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu); unsigned long events; int ret; + struct vfio_group *vfio_group; vdev->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier; vdev->group_notifier.notifier_call = intel_vgpu_group_notifier; @@ -814,6 +816,14 @@ static int intel_vgpu_open(struct mdev_device *mdev) goto undo_iommu; } + vfio_group = vfio_group_get_external_user_from_dev(mdev_dev(mdev)); + if (IS_ERR_OR_NULL(vfio_group)) { + ret = !vfio_group ? -EFAULT : PTR_ERR(vfio_group); + gvt_vgpu_err("vfio_group_get_external_user_from_dev failed\n"); + goto undo_register; + } + vdev->vfio_group = vfio_group; + /* Take a module reference as mdev core doesn't take * a reference for vendor driver. */ @@ -830,6 +840,10 @@ static int intel_vgpu_open(struct mdev_device *mdev) return ret; undo_group: + vfio_group_put_external_user(vdev->vfio_group); + vdev->vfio_group = NULL; + +undo_register: vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, &vdev->group_notifier); @@ -884,6 +898,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu) kvmgt_guest_exit(info); intel_vgpu_release_msi_eventfd_ctx(vgpu); + vfio_group_put_external_user(vdev->vfio_group); vdev->kvm = NULL; vgpu->handle = 0; From b59b2a3ee567e5a30688e148556ae33a3196bc9d Mon Sep 17 00:00:00 2001 From: Yan Zhao Date: Thu, 12 Mar 2020 23:11:09 -0400 Subject: [PATCH 2/3] 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 Signed-off-by: Yan Zhao Reviewed-by: Zhenyu Wang Signed-off-by: Zhenyu Wang Link: http://patchwork.freedesktop.org/patch/msgid/20200313031109.7989-1-yan.y.zhao@intel.com --- drivers/gpu/drm/i915/gvt/kvmgt.c | 23 ++--------------------- 1 file changed, 2 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 811cee28ae06a..cee7376ba39d0 100644 --- 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, From ec7301d5146c9abe8aaf6e16e420ea3951018503 Mon Sep 17 00:00:00 2001 From: Yan Zhao Date: Thu, 12 Mar 2020 23:11:51 -0400 Subject: [PATCH 3/3] drm/i915/gvt: switch to user vfio_group_pin/upin_pages substitute vfio_pin_pages() and vfio_unpin_pages() with vfio_group_pin_pages() and vfio_group_unpin_pages(), so that it will not go through looking up, checking, referencing, dereferencing of VFIO group in each call. Signed-off-by: Yan Zhao Reviewed-by: Zhenyu Wang Signed-off-by: Zhenyu Wang Link: http://patchwork.freedesktop.org/patch/msgid/20200313031151.8042-1-yan.y.zhao@intel.com --- drivers/gpu/drm/i915/gvt/kvmgt.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index cee7376ba39d0..eee530453aa67 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -152,6 +152,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, unsigned long size) { struct drm_i915_private *i915 = vgpu->gvt->gt->i915; + struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu); int total_pages; int npage; int ret; @@ -161,7 +162,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, for (npage = 0; npage < total_pages; npage++) { unsigned long cur_gfn = gfn + npage; - ret = vfio_unpin_pages(mdev_dev(kvmgt_vdev(vgpu)->mdev), &cur_gfn, 1); + ret = vfio_group_unpin_pages(vdev->vfio_group, &cur_gfn, 1); drm_WARN_ON(&i915->drm, ret != 1); } } @@ -170,6 +171,7 @@ static void gvt_unpin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, unsigned long size, struct page **page) { + struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu); unsigned long base_pfn = 0; int total_pages; int npage; @@ -184,8 +186,8 @@ static int gvt_pin_guest_page(struct intel_vgpu *vgpu, unsigned long gfn, unsigned long cur_gfn = gfn + npage; unsigned long pfn; - ret = vfio_pin_pages(mdev_dev(kvmgt_vdev(vgpu)->mdev), &cur_gfn, 1, - IOMMU_READ | IOMMU_WRITE, &pfn); + ret = vfio_group_pin_pages(vdev->vfio_group, &cur_gfn, 1, + IOMMU_READ | IOMMU_WRITE, &pfn); if (ret != 1) { gvt_vgpu_err("vfio_pin_pages failed for gfn 0x%lx, ret %d\n", cur_gfn, ret);