[RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs

[RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs

[Liu, Yi L]

Shared Virtual Addressing (SVA), a.k.a, Shared Virtual Memory (SVM) on
Intel platforms allows address space sharing between device DMA and
applications. SVA can reduce programming complexity and enhance security.

To enable SVA, device needs to have PASID capability, which is a key
capability for SVA. This patchset exposes the device's PASID capability
to guest instead of hiding it from guest.

The second patch emulates PASID capability for VFs (Virtual Function) since
VFs don't implement such capability per PCIe spec. This patch emulates such
capability and expose to VM if the capability is enabled in PF (Physical
Function).

However, there is an open for PASID emulation. If PF driver disables PASID
capability at runtime, then it may be an issue. e.g. PF should not disable
PASID capability if there is guest using this capability on any VF related
to this PF. To solve it, may need to introduce a generic communication
framework between vfio-pci driver and PF drivers. Please feel free to give
your suggestions on it.

Liu Yi L (2):
  vfio/pci: Expose PCIe PASID capability to guest
  vfio/pci: Emulate PASID/PRI capability for VFs

 drivers/vfio/pci/vfio_pci_config.c | 321 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 318 insertions(+), 3 deletions(-)

-- 
2.7.4

[RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs

[Liu, Yi L]

Shared Virtual Addressing (SVA), a.k.a, Shared Virtual Memory (SVM) on
Intel platforms allows address space sharing between device DMA and
applications. SVA can reduce programming complexity and enhance security.

To enable SVA, device needs to have PASID capability, which is a key
capability for SVA. This patchset exposes the device's PASID capability
to guest instead of hiding it from guest.

The second patch emulates PASID capability for VFs (Virtual Function) since
VFs don't implement such capability per PCIe spec. This patch emulates such
capability and expose to VM if the capability is enabled in PF (Physical
Function).

However, there is an open for PASID emulation. If PF driver disables PASID
capability at runtime, then it may be an issue. e.g. PF should not disable
PASID capability if there is guest using this capability on any VF related
to this PF. To solve it, may need to introduce a generic communication
framework between vfio-pci driver and PF drivers. Please feel free to give
your suggestions on it.

Liu Yi L (2):
  vfio/pci: Expose PCIe PASID capability to guest
  vfio/pci: Emulate PASID/PRI capability for VFs

 drivers/vfio/pci/vfio_pci_config.c | 321 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 318 insertions(+), 3 deletions(-)

-- 
2.7.4

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[RFC v1 1/2] vfio/pci: Expose PCIe PASID capability to guest

[Liu, Yi L]

From: Liu Yi L <yi.l.liu@intel.com>

This patch exposes PCIe PASID capability to guest. Existing vfio_pci
driver hides it from guest by setting the capability length as 0 in
pci_ext_cap_length[].

This capability is required for vSVA enabling on pass-through PCIe
devices.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
 drivers/vfio/pci/vfio_pci_config.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 90c0b80..4b9af99 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -95,7 +95,7 @@ static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = {
 	[PCI_EXT_CAP_ID_LTR]	=	PCI_EXT_CAP_LTR_SIZEOF,
 	[PCI_EXT_CAP_ID_SECPCI]	=	0,	/* not yet */
 	[PCI_EXT_CAP_ID_PMUX]	=	0,	/* not yet */
-	[PCI_EXT_CAP_ID_PASID]	=	0,	/* not yet */
+	[PCI_EXT_CAP_ID_PASID]	=	PCI_EXT_CAP_PASID_SIZEOF,
 };
 
 /*
-- 
2.7.4

[RFC v1 1/2] vfio/pci: Expose PCIe PASID capability to guest

[Liu, Yi L]

From: Liu Yi L <yi.l.liu@intel.com>

This patch exposes PCIe PASID capability to guest. Existing vfio_pci
driver hides it from guest by setting the capability length as 0 in
pci_ext_cap_length[].

This capability is required for vSVA enabling on pass-through PCIe
devices.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
 drivers/vfio/pci/vfio_pci_config.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 90c0b80..4b9af99 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -95,7 +95,7 @@ static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX + 1] = {
 	[PCI_EXT_CAP_ID_LTR]	=	PCI_EXT_CAP_LTR_SIZEOF,
 	[PCI_EXT_CAP_ID_SECPCI]	=	0,	/* not yet */
 	[PCI_EXT_CAP_ID_PMUX]	=	0,	/* not yet */
-	[PCI_EXT_CAP_ID_PASID]	=	0,	/* not yet */
+	[PCI_EXT_CAP_ID_PASID]	=	PCI_EXT_CAP_PASID_SIZEOF,
 };
 
 /*
-- 
2.7.4

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[RFC v1 2/2] vfio/pci: Emulate PASID/PRI capability for VFs

[Liu, Yi L]

From: Liu Yi L <yi.l.liu@intel.com>

Per PCIe r5.0, sec 9.3.7.14, if a PF implements the PASID Capability, the
PF PASID configuration is shared by its VFs.  VFs must not implement their
own PASID Capability.

Per PCIe r5.0, sec 9.3.7.11, VFs must not implement the PRI Capability. If
the PF implements PRI, it is shared by the VFs.

On bare metal, it has been fixed by below efforts.
to PASID/PRI are
https://lkml.org/lkml/2019/9/5/996
https://lkml.org/lkml/2019/9/5/995

This patch adds emulated PASID/PRI capabilities for VFs when assigned to
VMs via vfio-pci driver. This is required for enabling vSVA on pass-through
VFs as VFs have no PASID/PRI capability structure in its configure space.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
 drivers/vfio/pci/vfio_pci_config.c | 319 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 317 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 4b9af99..fbd20c3 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1509,11 +1509,304 @@ static int vfio_cap_init(struct vfio_pci_device *vdev)
 	return 0;
 }
 
+static int vfio_fill_custom_vconfig_bytes(struct vfio_pci_device *vdev,
+					int offset, uint8_t *data, int size)
+{
+	int ret = 0, data_offset = 0;
+
+	while (size) {
+		int filled;
+
+		if (size >= 4 && !(offset % 4)) {
+			__le32 *dwordp = (__le32 *)&vdev->vconfig[offset];
+			u32 dword;
+
+			memcpy(&dword, data + data_offset, 4);
+			*dwordp = cpu_to_le32(dword);
+			filled = 4;
+		} else if (size >= 2 && !(offset % 2)) {
+			__le16 *wordp = (__le16 *)&vdev->vconfig[offset];
+			u16 word;
+
+			memcpy(&word, data + data_offset, 2);
+			*wordp = cpu_to_le16(word);
+			filled = 2;
+		} else {
+			u8 *byte = &vdev->vconfig[offset];
+
+			memcpy(byte, data + data_offset, 1);
+			filled = 1;
+		}
+
+		offset += filled;
+		data_offset += filled;
+		size -= filled;
+	}
+
+	return ret;
+}
+
+static int vfio_pci_get_ecap_content(struct pci_dev *pdev,
+					int cap, int cap_len, u8 *content)
+{
+	int pos, offset, len = cap_len, ret = 0;
+
+	pos = pci_find_ext_capability(pdev, cap);
+	if (!pos)
+		return -EINVAL;
+
+	offset = 0;
+	while (len) {
+		int fetched;
+
+		if (len >= 4 && !(pos % 4)) {
+			u32 *dwordp = (u32 *) (content + offset);
+			u32 dword;
+			__le32 *dwptr = (__le32 *) &dword;
+
+			ret = pci_read_config_dword(pdev, pos, &dword);
+			if (ret)
+				return ret;
+			*dwordp = le32_to_cpu(*dwptr);
+			fetched = 4;
+		} else if (len >= 2 && !(pos % 2)) {
+			u16 *wordp = (u16 *) (content + offset);
+			u16 word;
+			__le16 *wptr = (__le16 *) &word;
+
+			ret = pci_read_config_word(pdev, pos, &word);
+			if (ret)
+				return ret;
+			*wordp = le16_to_cpu(*wptr);
+			fetched = 2;
+		} else {
+			u8 *byte = (u8 *) (content + offset);
+
+			ret = pci_read_config_byte(pdev, pos, byte);
+			if (ret)
+				return ret;
+			fetched = 1;
+		}
+
+		pos += fetched;
+		offset += fetched;
+		len -= fetched;
+	}
+
+	return ret;
+}
+
+struct vfio_pci_pasid_cap_data {
+	u32 id:16;
+	u32 version:4;
+	u32 next:12;
+	union {
+		u16 cap_reg_val;
+		struct {
+			u16 rsv1:1;
+			u16 execs:1;
+			u16 prvs:1;
+			u16 rsv2:5;
+			u16 pasid_bits:5;
+			u16 rsv3:3;
+		};
+	} cap_reg;
+	union {
+		u16 control_reg_val;
+		struct {
+			u16 paside:1;
+			u16 exece:1;
+			u16 prve:1;
+			u16 rsv4:13;
+		};
+	} control_reg;
+};
+
+static int vfio_pci_add_pasid_cap(struct vfio_pci_device *vdev,
+				    struct pci_dev *pdev,
+				    u16 epos, u16 *next, __le32 **prevp)
+{
+	u8 *map = vdev->pci_config_map;
+	int ecap = PCI_EXT_CAP_ID_PASID;
+	int len = pci_ext_cap_length[ecap];
+	struct vfio_pci_pasid_cap_data pasid_cap;
+	struct vfio_pci_pasid_cap_data vpasid_cap;
+	int ret;
+
+	/*
+	 * If no cap filled in this function, should make sure the next
+	 * pointer points to current epos.
+	 */
+	*next = epos;
+
+	if (!len) {
+		pr_info("%s: VF %s hiding PASID capability\n",
+				__func__, dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	/* Add PASID capability*/
+	ret = vfio_pci_get_ecap_content(pdev, ecap,
+					len, (u8 *)&pasid_cap);
+	if (ret)
+		goto out;
+
+	if (!pasid_cap.control_reg.paside) {
+		pr_debug("%s: its PF's PASID capability is not enabled\n",
+			dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	memcpy(&vpasid_cap, &pasid_cap, len);
+
+	vpasid_cap.id = 0x18;
+	vpasid_cap.next = 0;
+	/* clear the control reg for guest */
+	memset(&vpasid_cap.control_reg, 0x0,
+			sizeof(vpasid_cap.control_reg));
+
+	memset(map + epos, vpasid_cap.id, len);
+	ret = vfio_fill_custom_vconfig_bytes(vdev, epos,
+					(u8 *)&vpasid_cap, len);
+	if (!ret) {
+		/*
+		 * Successfully filled in PASID cap, update
+		 * the next offset in previous cap header,
+		 * and also update caller about the offset
+		 * of next cap if any.
+		 */
+		u32 val = epos;
+		**prevp &= cpu_to_le32(~(0xffcU << 20));
+		**prevp |= cpu_to_le32(val << 20);
+		*prevp = (__le32 *)&vdev->vconfig[epos];
+		*next = epos + len;
+	}
+
+out:
+	return ret;
+}
+
+struct vfio_pci_pri_cap_data {
+	u32 id:16;
+	u32 version:4;
+	u32 next:12;
+	union {
+		u16 control_reg_val;
+		struct {
+			u16 enable:1;
+			u16 reset:1;
+			u16 rsv1:14;
+		};
+	} control_reg;
+	union {
+		u16 status_reg_val;
+		struct {
+			u16 rf:1;
+			u16 uprgi:1;
+			u16 rsv2:6;
+			u16 stop:1;
+			u16 rsv3:6;
+			u16 pasid_required:1;
+		};
+	} status_reg;
+	u32 prq_capacity;
+	u32 prq_quota;
+};
+
+static int vfio_pci_add_pri_cap(struct vfio_pci_device *vdev,
+				    struct pci_dev *pdev,
+				    u16 epos, u16 *next, __le32 **prevp)
+{
+	u8 *map = vdev->pci_config_map;
+	int ecap = PCI_EXT_CAP_ID_PRI;
+	int len = pci_ext_cap_length[ecap];
+	struct vfio_pci_pri_cap_data pri_cap;
+	struct vfio_pci_pri_cap_data vpri_cap;
+	int ret;
+
+	/*
+	 * If no cap filled in this function, should make sure the next
+	 * pointer points to current epos.
+	 */
+	*next = epos;
+
+	if (!len) {
+		pr_info("%s: VF %s hiding PRI capability\n",
+				__func__, dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	/* Add PASID capability*/
+	ret = vfio_pci_get_ecap_content(pdev, ecap,
+					len, (u8 *)&pri_cap);
+	if (ret)
+		goto out;
+
+	if (!pri_cap.control_reg.enable) {
+		pr_debug("%s: its PF's PRI capability is not enabled\n",
+			dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	memcpy(&vpri_cap, &pri_cap, len);
+
+	vpri_cap.id = 0x19;
+	vpri_cap.next = 0;
+	/* clear the control reg for guest */
+	memset(&vpri_cap.control_reg, 0x0,
+			sizeof(vpri_cap.control_reg));
+
+	memset(map + epos, vpri_cap.id, len);
+	ret = vfio_fill_custom_vconfig_bytes(vdev, epos,
+					(u8 *)&vpri_cap, len);
+	if (!ret) {
+		/*
+		 * Successfully filled in PASID cap, update
+		 * the next offset in previous cap header,
+		 * and also update caller about the offset
+		 * of next cap if any.
+		 */
+		u32 val = epos;
+		**prevp &= cpu_to_le32(~(0xffcU << 20));
+		**prevp |= cpu_to_le32(val << 20);
+		*prevp = (__le32 *)&vdev->vconfig[epos];
+		*next = epos + len;
+	}
+
+out:
+	return ret;
+}
+
+static int vfio_pci_add_emulated_cap_for_vf(struct vfio_pci_device *vdev,
+			struct pci_dev *pdev, u16 start_epos, __le32 *prev)
+{
+	__le32 *__prev = prev;
+	u16 epos = start_epos, epos_next = start_epos;
+	int ret = 0;
+
+	/* Add PASID capability*/
+	ret = vfio_pci_add_pasid_cap(vdev, pdev, epos,
+					&epos_next, &__prev);
+	if (ret)
+		return ret;
+
+	/* Add PRI capability */
+	epos = epos_next;
+	ret = vfio_pci_add_pri_cap(vdev, pdev, epos,
+				   &epos_next, &__prev);
+
+	return ret;
+}
+
 static int vfio_ecap_init(struct vfio_pci_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	u8 *map = vdev->pci_config_map;
-	u16 epos;
+	u16 epos, epos_max;
 	__le32 *prev = NULL;
 	int loops, ret, ecaps = 0;
 
@@ -1521,6 +1814,7 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 		return 0;
 
 	epos = PCI_CFG_SPACE_SIZE;
+	epos_max = PCI_CFG_SPACE_SIZE;
 
 	loops = (pdev->cfg_size - PCI_CFG_SPACE_SIZE) / PCI_CAP_SIZEOF;
 
@@ -1545,6 +1839,9 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 			}
 		}
 
+		if (epos_max <= (epos + len))
+			epos_max = epos + len;
+
 		if (!len) {
 			pci_info(pdev, "%s: hiding ecap %#x@%#x\n",
 				 __func__, ecap, epos);
@@ -1604,6 +1901,16 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 	if (!ecaps)
 		*(u32 *)&vdev->vconfig[PCI_CFG_SPACE_SIZE] = 0;
 
+	if (pdev->is_virtfn) {
+		struct pci_dev *physfn = pdev->physfn;
+
+		ret = vfio_pci_add_emulated_cap_for_vf(vdev,
+					physfn, epos_max, prev);
+		if (ret)
+			pr_info("%s, failed to add special caps for VF %s\n",
+				__func__, dev_name(&vdev->pdev->dev));
+	}
+
 	return 0;
 }
 
@@ -1748,6 +2055,13 @@ static size_t vfio_pci_cap_remaining_dword(struct vfio_pci_device *vdev,
 	return i;
 }
 
+static bool vfio_pci_need_virt_perm(struct pci_dev *pdev, u8 cap_id)
+{
+	return (pdev->is_virtfn &&
+		(cap_id == PCI_EXT_CAP_ID_PASID ||
+		 cap_id == PCI_EXT_CAP_ID_PRI));
+}
+
 static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
 				 size_t count, loff_t *ppos, bool iswrite)
 {
@@ -1781,7 +2095,8 @@ static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
 	if (cap_id == PCI_CAP_ID_INVALID) {
 		perm = &unassigned_perms;
 		cap_start = *ppos;
-	} else if (cap_id == PCI_CAP_ID_INVALID_VIRT) {
+	} else if (cap_id == PCI_CAP_ID_INVALID_VIRT ||
+		   vfio_pci_need_virt_perm(pdev, cap_id)) {
 		perm = &virt_perms;
 		cap_start = *ppos;
 	} else {
-- 
2.7.4

[RFC v1 2/2] vfio/pci: Emulate PASID/PRI capability for VFs

[Liu, Yi L]

From: Liu Yi L <yi.l.liu@intel.com>

Per PCIe r5.0, sec 9.3.7.14, if a PF implements the PASID Capability, the
PF PASID configuration is shared by its VFs.  VFs must not implement their
own PASID Capability.

Per PCIe r5.0, sec 9.3.7.11, VFs must not implement the PRI Capability. If
the PF implements PRI, it is shared by the VFs.

On bare metal, it has been fixed by below efforts.
to PASID/PRI are
https://lkml.org/lkml/2019/9/5/996
https://lkml.org/lkml/2019/9/5/995

This patch adds emulated PASID/PRI capabilities for VFs when assigned to
VMs via vfio-pci driver. This is required for enabling vSVA on pass-through
VFs as VFs have no PASID/PRI capability structure in its configure space.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
---
 drivers/vfio/pci/vfio_pci_config.c | 319 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 317 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 4b9af99..fbd20c3 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1509,11 +1509,304 @@ static int vfio_cap_init(struct vfio_pci_device *vdev)
 	return 0;
 }
 
+static int vfio_fill_custom_vconfig_bytes(struct vfio_pci_device *vdev,
+					int offset, uint8_t *data, int size)
+{
+	int ret = 0, data_offset = 0;
+
+	while (size) {
+		int filled;
+
+		if (size >= 4 && !(offset % 4)) {
+			__le32 *dwordp = (__le32 *)&vdev->vconfig[offset];
+			u32 dword;
+
+			memcpy(&dword, data + data_offset, 4);
+			*dwordp = cpu_to_le32(dword);
+			filled = 4;
+		} else if (size >= 2 && !(offset % 2)) {
+			__le16 *wordp = (__le16 *)&vdev->vconfig[offset];
+			u16 word;
+
+			memcpy(&word, data + data_offset, 2);
+			*wordp = cpu_to_le16(word);
+			filled = 2;
+		} else {
+			u8 *byte = &vdev->vconfig[offset];
+
+			memcpy(byte, data + data_offset, 1);
+			filled = 1;
+		}
+
+		offset += filled;
+		data_offset += filled;
+		size -= filled;
+	}
+
+	return ret;
+}
+
+static int vfio_pci_get_ecap_content(struct pci_dev *pdev,
+					int cap, int cap_len, u8 *content)
+{
+	int pos, offset, len = cap_len, ret = 0;
+
+	pos = pci_find_ext_capability(pdev, cap);
+	if (!pos)
+		return -EINVAL;
+
+	offset = 0;
+	while (len) {
+		int fetched;
+
+		if (len >= 4 && !(pos % 4)) {
+			u32 *dwordp = (u32 *) (content + offset);
+			u32 dword;
+			__le32 *dwptr = (__le32 *) &dword;
+
+			ret = pci_read_config_dword(pdev, pos, &dword);
+			if (ret)
+				return ret;
+			*dwordp = le32_to_cpu(*dwptr);
+			fetched = 4;
+		} else if (len >= 2 && !(pos % 2)) {
+			u16 *wordp = (u16 *) (content + offset);
+			u16 word;
+			__le16 *wptr = (__le16 *) &word;
+
+			ret = pci_read_config_word(pdev, pos, &word);
+			if (ret)
+				return ret;
+			*wordp = le16_to_cpu(*wptr);
+			fetched = 2;
+		} else {
+			u8 *byte = (u8 *) (content + offset);
+
+			ret = pci_read_config_byte(pdev, pos, byte);
+			if (ret)
+				return ret;
+			fetched = 1;
+		}
+
+		pos += fetched;
+		offset += fetched;
+		len -= fetched;
+	}
+
+	return ret;
+}
+
+struct vfio_pci_pasid_cap_data {
+	u32 id:16;
+	u32 version:4;
+	u32 next:12;
+	union {
+		u16 cap_reg_val;
+		struct {
+			u16 rsv1:1;
+			u16 execs:1;
+			u16 prvs:1;
+			u16 rsv2:5;
+			u16 pasid_bits:5;
+			u16 rsv3:3;
+		};
+	} cap_reg;
+	union {
+		u16 control_reg_val;
+		struct {
+			u16 paside:1;
+			u16 exece:1;
+			u16 prve:1;
+			u16 rsv4:13;
+		};
+	} control_reg;
+};
+
+static int vfio_pci_add_pasid_cap(struct vfio_pci_device *vdev,
+				    struct pci_dev *pdev,
+				    u16 epos, u16 *next, __le32 **prevp)
+{
+	u8 *map = vdev->pci_config_map;
+	int ecap = PCI_EXT_CAP_ID_PASID;
+	int len = pci_ext_cap_length[ecap];
+	struct vfio_pci_pasid_cap_data pasid_cap;
+	struct vfio_pci_pasid_cap_data vpasid_cap;
+	int ret;
+
+	/*
+	 * If no cap filled in this function, should make sure the next
+	 * pointer points to current epos.
+	 */
+	*next = epos;
+
+	if (!len) {
+		pr_info("%s: VF %s hiding PASID capability\n",
+				__func__, dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	/* Add PASID capability*/
+	ret = vfio_pci_get_ecap_content(pdev, ecap,
+					len, (u8 *)&pasid_cap);
+	if (ret)
+		goto out;
+
+	if (!pasid_cap.control_reg.paside) {
+		pr_debug("%s: its PF's PASID capability is not enabled\n",
+			dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	memcpy(&vpasid_cap, &pasid_cap, len);
+
+	vpasid_cap.id = 0x18;
+	vpasid_cap.next = 0;
+	/* clear the control reg for guest */
+	memset(&vpasid_cap.control_reg, 0x0,
+			sizeof(vpasid_cap.control_reg));
+
+	memset(map + epos, vpasid_cap.id, len);
+	ret = vfio_fill_custom_vconfig_bytes(vdev, epos,
+					(u8 *)&vpasid_cap, len);
+	if (!ret) {
+		/*
+		 * Successfully filled in PASID cap, update
+		 * the next offset in previous cap header,
+		 * and also update caller about the offset
+		 * of next cap if any.
+		 */
+		u32 val = epos;
+		**prevp &= cpu_to_le32(~(0xffcU << 20));
+		**prevp |= cpu_to_le32(val << 20);
+		*prevp = (__le32 *)&vdev->vconfig[epos];
+		*next = epos + len;
+	}
+
+out:
+	return ret;
+}
+
+struct vfio_pci_pri_cap_data {
+	u32 id:16;
+	u32 version:4;
+	u32 next:12;
+	union {
+		u16 control_reg_val;
+		struct {
+			u16 enable:1;
+			u16 reset:1;
+			u16 rsv1:14;
+		};
+	} control_reg;
+	union {
+		u16 status_reg_val;
+		struct {
+			u16 rf:1;
+			u16 uprgi:1;
+			u16 rsv2:6;
+			u16 stop:1;
+			u16 rsv3:6;
+			u16 pasid_required:1;
+		};
+	} status_reg;
+	u32 prq_capacity;
+	u32 prq_quota;
+};
+
+static int vfio_pci_add_pri_cap(struct vfio_pci_device *vdev,
+				    struct pci_dev *pdev,
+				    u16 epos, u16 *next, __le32 **prevp)
+{
+	u8 *map = vdev->pci_config_map;
+	int ecap = PCI_EXT_CAP_ID_PRI;
+	int len = pci_ext_cap_length[ecap];
+	struct vfio_pci_pri_cap_data pri_cap;
+	struct vfio_pci_pri_cap_data vpri_cap;
+	int ret;
+
+	/*
+	 * If no cap filled in this function, should make sure the next
+	 * pointer points to current epos.
+	 */
+	*next = epos;
+
+	if (!len) {
+		pr_info("%s: VF %s hiding PRI capability\n",
+				__func__, dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	/* Add PASID capability*/
+	ret = vfio_pci_get_ecap_content(pdev, ecap,
+					len, (u8 *)&pri_cap);
+	if (ret)
+		goto out;
+
+	if (!pri_cap.control_reg.enable) {
+		pr_debug("%s: its PF's PRI capability is not enabled\n",
+			dev_name(&vdev->pdev->dev));
+		ret = 0;
+		goto out;
+	}
+
+	memcpy(&vpri_cap, &pri_cap, len);
+
+	vpri_cap.id = 0x19;
+	vpri_cap.next = 0;
+	/* clear the control reg for guest */
+	memset(&vpri_cap.control_reg, 0x0,
+			sizeof(vpri_cap.control_reg));
+
+	memset(map + epos, vpri_cap.id, len);
+	ret = vfio_fill_custom_vconfig_bytes(vdev, epos,
+					(u8 *)&vpri_cap, len);
+	if (!ret) {
+		/*
+		 * Successfully filled in PASID cap, update
+		 * the next offset in previous cap header,
+		 * and also update caller about the offset
+		 * of next cap if any.
+		 */
+		u32 val = epos;
+		**prevp &= cpu_to_le32(~(0xffcU << 20));
+		**prevp |= cpu_to_le32(val << 20);
+		*prevp = (__le32 *)&vdev->vconfig[epos];
+		*next = epos + len;
+	}
+
+out:
+	return ret;
+}
+
+static int vfio_pci_add_emulated_cap_for_vf(struct vfio_pci_device *vdev,
+			struct pci_dev *pdev, u16 start_epos, __le32 *prev)
+{
+	__le32 *__prev = prev;
+	u16 epos = start_epos, epos_next = start_epos;
+	int ret = 0;
+
+	/* Add PASID capability*/
+	ret = vfio_pci_add_pasid_cap(vdev, pdev, epos,
+					&epos_next, &__prev);
+	if (ret)
+		return ret;
+
+	/* Add PRI capability */
+	epos = epos_next;
+	ret = vfio_pci_add_pri_cap(vdev, pdev, epos,
+				   &epos_next, &__prev);
+
+	return ret;
+}
+
 static int vfio_ecap_init(struct vfio_pci_device *vdev)
 {
 	struct pci_dev *pdev = vdev->pdev;
 	u8 *map = vdev->pci_config_map;
-	u16 epos;
+	u16 epos, epos_max;
 	__le32 *prev = NULL;
 	int loops, ret, ecaps = 0;
 
@@ -1521,6 +1814,7 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 		return 0;
 
 	epos = PCI_CFG_SPACE_SIZE;
+	epos_max = PCI_CFG_SPACE_SIZE;
 
 	loops = (pdev->cfg_size - PCI_CFG_SPACE_SIZE) / PCI_CAP_SIZEOF;
 
@@ -1545,6 +1839,9 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 			}
 		}
 
+		if (epos_max <= (epos + len))
+			epos_max = epos + len;
+
 		if (!len) {
 			pci_info(pdev, "%s: hiding ecap %#x@%#x\n",
 				 __func__, ecap, epos);
@@ -1604,6 +1901,16 @@ static int vfio_ecap_init(struct vfio_pci_device *vdev)
 	if (!ecaps)
 		*(u32 *)&vdev->vconfig[PCI_CFG_SPACE_SIZE] = 0;
 
+	if (pdev->is_virtfn) {
+		struct pci_dev *physfn = pdev->physfn;
+
+		ret = vfio_pci_add_emulated_cap_for_vf(vdev,
+					physfn, epos_max, prev);
+		if (ret)
+			pr_info("%s, failed to add special caps for VF %s\n",
+				__func__, dev_name(&vdev->pdev->dev));
+	}
+
 	return 0;
 }
 
@@ -1748,6 +2055,13 @@ static size_t vfio_pci_cap_remaining_dword(struct vfio_pci_device *vdev,
 	return i;
 }
 
+static bool vfio_pci_need_virt_perm(struct pci_dev *pdev, u8 cap_id)
+{
+	return (pdev->is_virtfn &&
+		(cap_id == PCI_EXT_CAP_ID_PASID ||
+		 cap_id == PCI_EXT_CAP_ID_PRI));
+}
+
 static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
 				 size_t count, loff_t *ppos, bool iswrite)
 {
@@ -1781,7 +2095,8 @@ static ssize_t vfio_config_do_rw(struct vfio_pci_device *vdev, char __user *buf,
 	if (cap_id == PCI_CAP_ID_INVALID) {
 		perm = &unassigned_perms;
 		cap_start = *ppos;
-	} else if (cap_id == PCI_CAP_ID_INVALID_VIRT) {
+	} else if (cap_id == PCI_CAP_ID_INVALID_VIRT ||
+		   vfio_pci_need_virt_perm(pdev, cap_id)) {
 		perm = &virt_perms;
 		cap_start = *ppos;
 	} else {
-- 
2.7.4

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RE: [RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs

[Liu, Yi L]

Hi Alex,

Any comment on this series?

Regards,
Yi Liu

> From: Liu, Yi L
> Sent: Wednesday, January 29, 2020 8:19 PM
> To: alex.williamson@redhat.com; eric.auger@redhat.com
> Subject: [RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs
> 
> Shared Virtual Addressing (SVA), a.k.a, Shared Virtual Memory (SVM) on Intel
> platforms allows address space sharing between device DMA and applications. SVA
> can reduce programming complexity and enhance security.
> 
> To enable SVA, device needs to have PASID capability, which is a key capability for
> SVA. This patchset exposes the device's PASID capability to guest instead of hiding it
> from guest.
> 
> The second patch emulates PASID capability for VFs (Virtual Function) since VFs don't
> implement such capability per PCIe spec. This patch emulates such capability and
> expose to VM if the capability is enabled in PF (Physical Function).
> 
> However, there is an open for PASID emulation. If PF driver disables PASID capability
> at runtime, then it may be an issue. e.g. PF should not disable PASID capability if
> there is guest using this capability on any VF related to this PF. To solve it, may need
> to introduce a generic communication framework between vfio-pci driver and PF
> drivers. Please feel free to give your suggestions on it.
> 
> Liu Yi L (2):
>   vfio/pci: Expose PCIe PASID capability to guest
>   vfio/pci: Emulate PASID/PRI capability for VFs
> 
>  drivers/vfio/pci/vfio_pci_config.c | 321
> ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 318 insertions(+), 3 deletions(-)
> 
> --
> 2.7.4

RE: [RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs

[Liu, Yi L]

Hi Alex,

Any comment on this series?

Regards,
Yi Liu

> From: Liu, Yi L
> Sent: Wednesday, January 29, 2020 8:19 PM
> To: alex.williamson@redhat.com; eric.auger@redhat.com
> Subject: [RFC v1 0/2] vfio/pci: expose device's PASID capability to VMs
> 
> Shared Virtual Addressing (SVA), a.k.a, Shared Virtual Memory (SVM) on Intel
> platforms allows address space sharing between device DMA and applications. SVA
> can reduce programming complexity and enhance security.
> 
> To enable SVA, device needs to have PASID capability, which is a key capability for
> SVA. This patchset exposes the device's PASID capability to guest instead of hiding it
> from guest.
> 
> The second patch emulates PASID capability for VFs (Virtual Function) since VFs don't
> implement such capability per PCIe spec. This patch emulates such capability and
> expose to VM if the capability is enabled in PF (Physical Function).
> 
> However, there is an open for PASID emulation. If PF driver disables PASID capability
> at runtime, then it may be an issue. e.g. PF should not disable PASID capability if
> there is guest using this capability on any VF related to this PF. To solve it, may need
> to introduce a generic communication framework between vfio-pci driver and PF
> drivers. Please feel free to give your suggestions on it.
> 
> Liu Yi L (2):
>   vfio/pci: Expose PCIe PASID capability to guest
>   vfio/pci: Emulate PASID/PRI capability for VFs
> 
>  drivers/vfio/pci/vfio_pci_config.c | 321
> ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 318 insertions(+), 3 deletions(-)
> 
> --
> 2.7.4

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