[RFC PATCH 19/30] vfio/pci: Add TSM TDI bind/unbind IOCTLs for TEE-IO support

[Xu Yilun <yilun.xu@linux.intel.com>]

Add new IOCTLs to do TSM based TDI bind/unbind. These IOCTLs are
expected to be called by userspace when CoCo VM issues TDI bind/unbind
command to VMM. Specifically for TDX Connect, these commands are some
secure Hypervisor call named GHCI (Guest-Hypervisor Communication
Interface).

The TSM TDI bind/unbind operations are expected to be initiated by a
running CoCo VM, which already have the legacy assigned device in place.
The TSM bind operation is to request VMM make all secure configurations
to support device work as a TDI, and then issue TDISP messages to move
the TDI to CONFIG_LOCKED or RUN state, waiting for guest's attestation.

Do TSM Unbind before vfio_pci_core_disable(), otherwise will lead
device to TDISP ERROR state.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
---
 drivers/vfio/iommufd.c           | 22 ++++++++++
 drivers/vfio/pci/vfio_pci_core.c | 74 ++++++++++++++++++++++++++++++++
 include/linux/vfio.h             |  7 +++
 include/linux/vfio_pci_core.h    |  1 +
 include/uapi/linux/vfio.h        | 42 ++++++++++++++++++
 5 files changed, 146 insertions(+)

diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 3441d24538a8..33fd20ffaeee 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -297,3 +297,25 @@ void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev)
 	vdev->iommufd_attached = false;
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_detach_ioas);
+
+int vfio_iommufd_tsm_bind(struct vfio_device *vdev, u32 vdevice_id)
+{
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (WARN_ON(!vdev->iommufd_device))
+		return -EINVAL;
+
+	return iommufd_device_tsm_bind(vdev->iommufd_device, vdevice_id);
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_tsm_bind);
+
+void vfio_iommufd_tsm_unbind(struct vfio_device *vdev)
+{
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (WARN_ON(!vdev->iommufd_device))
+		return;
+
+	iommufd_device_tsm_unbind(vdev->iommufd_device);
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_tsm_unbind);
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 116964057b0b..92544e54c9c3 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -692,6 +692,13 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
 #if IS_ENABLED(CONFIG_EEH)
 	eeh_dev_release(vdev->pdev);
 #endif
+
+	if (vdev->is_tsm_bound) {
+		vfio_iommufd_tsm_unbind(&vdev->vdev);
+		pci_release_regions(vdev->pdev);
+		vdev->is_tsm_bound = false;
+	}
+
 	vfio_pci_core_disable(vdev);
 
 	vfio_pci_dma_buf_cleanup(vdev);
@@ -1447,6 +1454,69 @@ static int vfio_pci_ioctl_ioeventfd(struct vfio_pci_core_device *vdev,
 				  ioeventfd.fd);
 }
 
+static int vfio_pci_ioctl_tsm_bind(struct vfio_pci_core_device *vdev,
+				   void __user *arg)
+{
+	unsigned long minsz = offsetofend(struct vfio_pci_tsm_bind, vdevice_id);
+	struct vfio_pci_tsm_bind tsm_bind;
+	struct pci_dev *pdev = vdev->pdev;
+	int ret;
+
+	if (copy_from_user(&tsm_bind, arg, minsz))
+		return -EFAULT;
+
+	if (tsm_bind.argsz < minsz || tsm_bind.flags)
+		return -EINVAL;
+
+	mutex_lock(&vdev->vdev.dev_set->lock);
+
+	/* To ensure no host side MMIO access is possible */
+	ret = pci_request_regions_exclusive(pdev, "vfio-pci-tsm");
+	if (ret)
+		goto out_unlock;
+
+	ret = vfio_iommufd_tsm_bind(&vdev->vdev, tsm_bind.vdevice_id);
+	if (ret)
+		goto out_release_region;
+
+	vdev->is_tsm_bound = true;
+	mutex_unlock(&vdev->vdev.dev_set->lock);
+
+	return 0;
+
+out_release_region:
+	pci_release_regions(pdev);
+out_unlock:
+	mutex_unlock(&vdev->vdev.dev_set->lock);
+	return ret;
+}
+
+static int vfio_pci_ioctl_tsm_unbind(struct vfio_pci_core_device *vdev,
+				     void __user *arg)
+{
+	unsigned long minsz = offsetofend(struct vfio_pci_tsm_unbind, flags);
+	struct vfio_pci_tsm_unbind tsm_unbind;
+	struct pci_dev *pdev = vdev->pdev;
+
+	if (copy_from_user(&tsm_unbind, arg, minsz))
+		return -EFAULT;
+
+	if (tsm_unbind.argsz < minsz || tsm_unbind.flags)
+		return -EINVAL;
+
+	mutex_lock(&vdev->vdev.dev_set->lock);
+
+	if (!vdev->is_tsm_bound)
+		return 0;
+
+	vfio_iommufd_tsm_unbind(&vdev->vdev);
+	pci_release_regions(pdev);
+	vdev->is_tsm_bound = false;
+	mutex_unlock(&vdev->vdev.dev_set->lock);
+
+	return 0;
+}
+
 long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
 			 unsigned long arg)
 {
@@ -1471,6 +1541,10 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
 		return vfio_pci_ioctl_reset(vdev, uarg);
 	case VFIO_DEVICE_SET_IRQS:
 		return vfio_pci_ioctl_set_irqs(vdev, uarg);
+	case VFIO_DEVICE_TSM_BIND:
+		return vfio_pci_ioctl_tsm_bind(vdev, uarg);
+	case VFIO_DEVICE_TSM_UNBIND:
+		return vfio_pci_ioctl_tsm_unbind(vdev, uarg);
 	default:
 		return -ENOTTY;
 	}
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index d521d2c01a92..747b94bb9758 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -70,6 +70,7 @@ struct vfio_device {
 	struct iommufd_device *iommufd_device;
 	struct ida pasids;
 	u8 iommufd_attached:1;
+	u8 iommufd_tsm_bound:1;
 #endif
 	u8 cdev_opened:1;
 #ifdef CONFIG_DEBUG_FS
@@ -155,6 +156,8 @@ int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
 void vfio_iommufd_emulated_unbind(struct vfio_device *vdev);
 int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
 void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev);
+int vfio_iommufd_tsm_bind(struct vfio_device *vdev, u32 vdevice_id);
+void vfio_iommufd_tsm_unbind(struct vfio_device *vdev);
 #else
 static inline struct iommufd_ctx *
 vfio_iommufd_device_ictx(struct vfio_device *vdev)
@@ -190,6 +193,10 @@ vfio_iommufd_get_dev_id(struct vfio_device *vdev, struct iommufd_ctx *ictx)
 	((int (*)(struct vfio_device *vdev, u32 *pt_id)) NULL)
 #define vfio_iommufd_emulated_detach_ioas \
 	((void (*)(struct vfio_device *vdev)) NULL)
+#define vfio_iommufd_tsm_bind \
+	((int (*)(struct vfio_device *vdev, u32 vdevice_id)) NULL)
+#define vfio_iommufd_tsm_unbind \
+	((void (*)(struct vfio_device *vdev)) NULL)
 #endif
 
 static inline bool vfio_device_cdev_opened(struct vfio_device *device)
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index da5d8955ae56..b2982100221f 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -80,6 +80,7 @@ struct vfio_pci_core_device {
 	bool			needs_pm_restore:1;
 	bool			pm_intx_masked:1;
 	bool			pm_runtime_engaged:1;
+	bool			is_tsm_bound:1;
 	struct pci_saved_state	*pci_saved_state;
 	struct pci_saved_state	*pm_save;
 	int			ioeventfds_nr;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 9445fa36efd3..16bd93a5b427 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1493,6 +1493,48 @@ struct vfio_device_feature_dma_buf {
 	struct vfio_region_dma_range dma_ranges[];
 };
 
+/*
+ * Upon VFIO_DEVICE_TSM_BIND, Put the device in TSM Bind state.
+ *
+ * @argsz:	User filled size of this data.
+ * @flags:	Must be 0.
+ * @vdevice_id:	Input the target id which can represent an vdevice allocated
+ *		via iommufd subsystem.
+ *
+ * The vdevice holds all virtualization information needed for TSM Bind.
+ * TSM Bind means host finishes all host side trusted configurations to build
+ * a Tee Device Interface(TDI), then put the TDI in TDISP CONFIG_LOCKED or RUN
+ * state, waiting for guest's attestation. IOMMUFD finds all virtualization
+ * information from vdevice_id, and executes the TSM Bind. VFIO should be aware
+ * some operations (e.g. reset, toggle MSE, private MMIO access) to physical
+ * device impacts TSM Bind, so never do them or do them only after TSM Unbind.
+ * This IOCTL is only allowed on cdev fds.
+ */
+struct vfio_pci_tsm_bind {
+	__u32	argsz;
+	__u32	flags;
+	__u32	vdevice_id;
+	__u32	pad;
+};
+
+#define VFIO_DEVICE_TSM_BIND		_IO(VFIO_TYPE, VFIO_BASE + 22)
+
+/*
+ * Upon VFIO_DEVICE_TSM_UNBIND, put the device in TSM Unbind state.
+ *
+ * @argsz:	User filled size of this data.
+ * @flags:	Must be 0.
+ *
+ * TSM Unbind means host removes all trusted configurations, and put the TDI in
+ * CONFIG_UNLOCKED TDISP state.
+ */
+struct vfio_pci_tsm_unbind {
+	__u32	argsz;
+	__u32	flags;
+};
+
+#define VFIO_DEVICE_TSM_UNBIND		_IO(VFIO_TYPE, VFIO_BASE + 23)
+
 /* -------- API for Type1 VFIO IOMMU -------- */
 
 /**
-- 
2.25.1