* [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices
@ 2021-08-18 13:01 Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 1/8] PCI: Use cached Device Capabilities Register Dongdong Liu
` (7 more replies)
0 siblings, 8 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
10-Bit Tag capability, introduced in PCIe-4.0 increases the total Tag
field size from 8 bits to 10 bits.
This patchset is to enable 10-Bit tag for PCIe EP devices (include VF).
V7->V8:
- Add a kernel parameter pcie_tag_peer2peer to disable 10-bit tags.
- Provide sysfs file to enable 10-bit tags.
- Remove [PATCH V7 6/9] PCI: Enable 10-Bit Tag support for PCIe RP devices.
- Rebased on v5.14-rc6.
- Fix some other comments. Thanks to Bjorn who gave a lot of review comments.
V6->V7:
- Rebased on v5.14-rc3.
- Change the "pci=disable_10bit_tag=" parameter to sysfs file to disable
10-Bit Tag Requester when need for p2pdma suggested by Leon.
- Fix comment for p2pdma 10-bit tag check.
V5->V6:
- Rebased on v5.14-rc2.
- Add Reviewed-by: Christoph Hellwig <hch@lst.de> in [PATCH V6 2/8].
- PCI: Add "pci=disable_10bit_tag=" parameter for peer-to-peer support.
- Add a 10-bit tag check in P2PDMA.
- Simplified implementation in [PATCH V6 6/8].
- Fix some comments in [PATCH V6 4/8].
V4->V5:
- Fix warning variable 'capa' is uninitialized.
- Fix warning unused variable 'pchild'.
V3->V4:
- Get the value of pcie_devcap2 in set_pcie_port_type().
- Add Reviewed-by: Christoph Hellwig <hch@lst.de> in [PATCH V4 1/6],
[PATCH V4 3/6], [PATCH V4 4/6], [PATCH V4 5/6].
- Fix some code style.
- Rebased on v5.13-rc6.
V2->V3:
- Use cached Device Capabilities Register suggested by Christoph.
- Fix code style to avoid > 80 char lines.
- Rename devcap2 to pcie_devcap2.
V1->V2: Fix some comments by Christoph.
- Store the devcap2 value in the pci_dev instead of reading it multiple
times.
- Change pci_info to pci_dbg to avoid the noisy log.
- Rename ext_10bit_tag_comp_path to ext_10bit_tag.
- Fix the compile error.
- Rebased on v5.13-rc1.
Dongdong Liu (8):
PCI: Use cached Device Capabilities Register
PCI: Use cached Device Capabilities 2 Register
PCI: Add 10-Bit Tag register definitions
PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices
PCI/IOV: Add 10-Bit Tag sysfs files for VF devices
PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA
PCI: Enable 10-Bit Tag support for PCIe Endpoint device
PCI/IOV: Enable 10-Bit Tag support for PCIe VF devices
Documentation/ABI/testing/sysfs-bus-pci | 41 ++++++++++++-
Documentation/admin-guide/kernel-parameters.txt | 5 ++
drivers/media/pci/cobalt/cobalt-driver.c | 5 +-
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 4 +-
drivers/pci/iov.c | 68 +++++++++++++++++++++
drivers/pci/p2pdma.c | 48 +++++++++++++++
drivers/pci/pci-sysfs.c | 79 +++++++++++++++++++++++++
drivers/pci/pci.c | 18 +++---
drivers/pci/pci.h | 10 ++++
drivers/pci/pcie/aspm.c | 11 ++--
drivers/pci/probe.c | 79 ++++++++++++++++++++-----
drivers/pci/quirks.c | 3 +-
include/linux/pci.h | 3 +
include/uapi/linux/pci_regs.h | 5 ++
14 files changed, 341 insertions(+), 38 deletions(-)
--
2.7.4
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH V8 1/8] PCI: Use cached Device Capabilities Register
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 2/8] PCI: Use cached Device Capabilities 2 Register Dongdong Liu
` (6 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
It will make sense to store the pcie_devcap value in the pci_dev
structure instead of reading Device Capabilities Register multiple
times. The fisrt place to use pcie_devcap is in set_pcie_port_type(),
get the pcie_devcap value here, then use cached pcie_devcap in the
needed place.
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
drivers/media/pci/cobalt/cobalt-driver.c | 5 +++--
drivers/pci/pci.c | 5 +----
drivers/pci/pcie/aspm.c | 11 ++++-------
drivers/pci/probe.c | 11 +++--------
drivers/pci/quirks.c | 3 +--
include/linux/pci.h | 1 +
6 files changed, 13 insertions(+), 23 deletions(-)
diff --git a/drivers/media/pci/cobalt/cobalt-driver.c b/drivers/media/pci/cobalt/cobalt-driver.c
index 16af58f..23c6436 100644
--- a/drivers/media/pci/cobalt/cobalt-driver.c
+++ b/drivers/media/pci/cobalt/cobalt-driver.c
@@ -193,11 +193,12 @@ void cobalt_pcie_status_show(struct cobalt *cobalt)
return;
/* Device */
- pcie_capability_read_dword(pci_dev, PCI_EXP_DEVCAP, &capa);
pcie_capability_read_word(pci_dev, PCI_EXP_DEVCTL, &ctrl);
pcie_capability_read_word(pci_dev, PCI_EXP_DEVSTA, &stat);
cobalt_info("PCIe device capability 0x%08x: Max payload %d\n",
- capa, get_payload_size(capa & PCI_EXP_DEVCAP_PAYLOAD));
+ pci_dev->pcie_devcap,
+ get_payload_size(pci_dev->pcie_devcap &
+ PCI_EXP_DEVCAP_PAYLOAD));
cobalt_info("PCIe device control 0x%04x: Max payload %d. Max read request %d\n",
ctrl,
get_payload_size((ctrl & PCI_EXP_DEVCTL_PAYLOAD) >> 5),
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index aacf575..dc3bfb2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4630,13 +4630,10 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction);
*/
bool pcie_has_flr(struct pci_dev *dev)
{
- u32 cap;
-
if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
return false;
- pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
- return cap & PCI_EXP_DEVCAP_FLR;
+ return dev->pcie_devcap & PCI_EXP_DEVCAP_FLR;
}
EXPORT_SYMBOL_GPL(pcie_has_flr);
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 013a47f..db944f6 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -660,7 +660,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
/* Get and check endpoint acceptable latencies */
list_for_each_entry(child, &linkbus->devices, bus_list) {
- u32 reg32, encoding;
+ u32 encoding;
struct aspm_latency *acceptable =
&link->acceptable[PCI_FUNC(child->devfn)];
@@ -668,12 +668,11 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
continue;
- pcie_capability_read_dword(child, PCI_EXP_DEVCAP, ®32);
/* Calculate endpoint L0s acceptable latency */
- encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
+ encoding = (child->pcie_devcap & PCI_EXP_DEVCAP_L0S) >> 6;
acceptable->l0s = calc_l0s_acceptable(encoding);
/* Calculate endpoint L1 acceptable latency */
- encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
+ encoding = (child->pcie_devcap & PCI_EXP_DEVCAP_L1) >> 9;
acceptable->l1 = calc_l1_acceptable(encoding);
pcie_aspm_check_latency(child);
@@ -808,7 +807,6 @@ static void free_link_state(struct pcie_link_state *link)
static int pcie_aspm_sanity_check(struct pci_dev *pdev)
{
struct pci_dev *child;
- u32 reg32;
/*
* Some functions in a slot might not all be PCIe functions,
@@ -831,8 +829,7 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
* Disable ASPM for pre-1.1 PCIe device, we follow MS to use
* RBER bit to determine if a function is 1.1 version device
*/
- pcie_capability_read_dword(child, PCI_EXP_DEVCAP, ®32);
- if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
+ if (!(child->pcie_devcap & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
pci_info(child, "disabling ASPM on pre-1.1 PCIe device. You can enable it with 'pcie_aspm=force'\n");
return -EINVAL;
}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 79177ac..cc700f6 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1498,8 +1498,8 @@ void set_pcie_port_type(struct pci_dev *pdev)
pdev->pcie_cap = pos;
pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, ®16);
pdev->pcie_flags_reg = reg16;
- pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16);
- pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
+ pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP, &pdev->pcie_devcap);
+ pdev->pcie_mpss = pdev->pcie_devcap & PCI_EXP_DEVCAP_PAYLOAD;
parent = pci_upstream_bridge(pdev);
if (!parent)
@@ -2031,18 +2031,13 @@ static void pci_configure_mps(struct pci_dev *dev)
int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
{
struct pci_host_bridge *host;
- u32 cap;
u16 ctl;
int ret;
if (!pci_is_pcie(dev))
return 0;
- ret = pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &cap);
- if (ret)
- return 0;
-
- if (!(cap & PCI_EXP_DEVCAP_EXT_TAG))
+ if (!(dev->pcie_devcap & PCI_EXP_DEVCAP_EXT_TAG))
return 0;
ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL, &ctl);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6d74386..2b405c5 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5173,8 +5173,7 @@ static void quirk_intel_qat_vf_cap(struct pci_dev *pdev)
pdev->pcie_cap = pos;
pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, ®16);
pdev->pcie_flags_reg = reg16;
- pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP, ®16);
- pdev->pcie_mpss = reg16 & PCI_EXP_DEVCAP_PAYLOAD;
+ pdev->pcie_mpss = pdev->pcie_devcap & PCI_EXP_DEVCAP_PAYLOAD;
pdev->cfg_size = PCI_CFG_SPACE_EXP_SIZE;
if (pci_read_config_dword(pdev, PCI_CFG_SPACE_SIZE, &status) !=
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 540b377..aee7c85 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -340,6 +340,7 @@ struct pci_dev {
u8 rom_base_reg; /* Config register controlling ROM */
u8 pin; /* Interrupt pin this device uses */
u16 pcie_flags_reg; /* Cached PCIe Capabilities Register */
+ u32 pcie_devcap; /* Cached Device Capabilities Register */
unsigned long *dma_alias_mask;/* Mask of enabled devfn aliases */
struct pci_driver *driver; /* Driver bound to this device */
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 2/8] PCI: Use cached Device Capabilities 2 Register
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 1/8] PCI: Use cached Device Capabilities Register Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 3/8] PCI: Add 10-Bit Tag register definitions Dongdong Liu
` (5 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
It will make sense to store the pcie_devcap2 value in the pci_dev
structure instead of reading Device Capabilities 2 Register multiple
times. Get the pcie_devcap2 value set_pcie_port_type(), then use
cached pcie_devcap2 in the needed place.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c | 4 +---
drivers/pci/pci.c | 9 ++++-----
drivers/pci/probe.c | 10 ++++------
include/linux/pci.h | 2 ++
4 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index dbf9a0e..a8e1e22 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -6304,7 +6304,6 @@ static int cxgb4_iov_configure(struct pci_dev *pdev, int num_vfs)
struct pci_dev *pbridge;
struct port_info *pi;
char name[IFNAMSIZ];
- u32 devcap2;
u16 flags;
/* If we want to instantiate Virtual Functions, then our
@@ -6314,10 +6313,9 @@ static int cxgb4_iov_configure(struct pci_dev *pdev, int num_vfs)
*/
pbridge = pdev->bus->self;
pcie_capability_read_word(pbridge, PCI_EXP_FLAGS, &flags);
- pcie_capability_read_dword(pbridge, PCI_EXP_DEVCAP2, &devcap2);
if ((flags & PCI_EXP_FLAGS_VERS) < 2 ||
- !(devcap2 & PCI_EXP_DEVCAP2_ARI)) {
+ !(pbridge->pcie_devcap2 & PCI_EXP_DEVCAP2_ARI)) {
/* Our parent bridge does not support ARI so issue a
* warning and skip instantiating the VFs. They
* won't be reachable.
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index dc3bfb2..d14c573 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3700,7 +3700,7 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask)
{
struct pci_bus *bus = dev->bus;
struct pci_dev *bridge;
- u32 cap, ctl2;
+ u32 ctl2;
if (!pci_is_pcie(dev))
return -EINVAL;
@@ -3724,19 +3724,18 @@ int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask)
while (bus->parent) {
bridge = bus->self;
- pcie_capability_read_dword(bridge, PCI_EXP_DEVCAP2, &cap);
-
switch (pci_pcie_type(bridge)) {
/* Ensure switch ports support AtomicOp routing */
case PCI_EXP_TYPE_UPSTREAM:
case PCI_EXP_TYPE_DOWNSTREAM:
- if (!(cap & PCI_EXP_DEVCAP2_ATOMIC_ROUTE))
+ if (!(bridge->pcie_devcap2 &
+ PCI_EXP_DEVCAP2_ATOMIC_ROUTE))
return -EINVAL;
break;
/* Ensure root port supports all the sizes we care about */
case PCI_EXP_TYPE_ROOT_PORT:
- if ((cap & cap_mask) != cap_mask)
+ if ((bridge->pcie_devcap2 & cap_mask) != cap_mask)
return -EINVAL;
break;
}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index cc700f6..c83245b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1500,6 +1500,7 @@ void set_pcie_port_type(struct pci_dev *pdev)
pdev->pcie_flags_reg = reg16;
pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP, &pdev->pcie_devcap);
pdev->pcie_mpss = pdev->pcie_devcap & PCI_EXP_DEVCAP_PAYLOAD;
+ pci_read_config_dword(pdev, pos + PCI_EXP_DEVCAP2, &pdev->pcie_devcap2);
parent = pci_upstream_bridge(pdev);
if (!parent)
@@ -2116,7 +2117,7 @@ static void pci_configure_ltr(struct pci_dev *dev)
#ifdef CONFIG_PCIEASPM
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
struct pci_dev *bridge;
- u32 cap, ctl;
+ u32 ctl;
if (!pci_is_pcie(dev))
return;
@@ -2124,8 +2125,7 @@ static void pci_configure_ltr(struct pci_dev *dev)
/* Read L1 PM substate capabilities */
dev->l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
- pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
- if (!(cap & PCI_EXP_DEVCAP2_LTR))
+ if (!(dev->pcie_devcap2 & PCI_EXP_DEVCAP2_LTR))
return;
pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl);
@@ -2165,13 +2165,11 @@ static void pci_configure_eetlp_prefix(struct pci_dev *dev)
#ifdef CONFIG_PCI_PASID
struct pci_dev *bridge;
int pcie_type;
- u32 cap;
if (!pci_is_pcie(dev))
return;
- pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
- if (!(cap & PCI_EXP_DEVCAP2_EE_PREFIX))
+ if (!(dev->pcie_devcap2 & PCI_EXP_DEVCAP2_EE_PREFIX))
return;
pcie_type = pci_pcie_type(dev);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index aee7c85..9aab67f 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -341,6 +341,8 @@ struct pci_dev {
u8 pin; /* Interrupt pin this device uses */
u16 pcie_flags_reg; /* Cached PCIe Capabilities Register */
u32 pcie_devcap; /* Cached Device Capabilities Register */
+ u32 pcie_devcap2; /* Cached Device Capabilities 2
+ Register */
unsigned long *dma_alias_mask;/* Mask of enabled devfn aliases */
struct pci_driver *driver; /* Driver bound to this device */
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 3/8] PCI: Add 10-Bit Tag register definitions
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 1/8] PCI: Use cached Device Capabilities Register Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 2/8] PCI: Use cached Device Capabilities 2 Register Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 4/8] PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices Dongdong Liu
` (4 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
Add 10-Bit Tag register definitions for use in subsequen patches.
See the PCIe 5.0 spec section 7.5.3.15 and 9.3.3.2.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
include/uapi/linux/pci_regs.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index e709ae8..cf1ddb8 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -648,6 +648,8 @@
#define PCI_EXP_DEVCAP2_ATOMIC_COMP64 0x00000100 /* 64b AtomicOp completion */
#define PCI_EXP_DEVCAP2_ATOMIC_COMP128 0x00000200 /* 128b AtomicOp completion */
#define PCI_EXP_DEVCAP2_LTR 0x00000800 /* Latency tolerance reporting */
+#define PCI_EXP_DEVCAP2_10BIT_TAG_COMP 0x00010000 /* 10-Bit Tag Completer Supported */
+#define PCI_EXP_DEVCAP2_10BIT_TAG_REQ 0x00020000 /* 10-Bit Tag Requester Supported */
#define PCI_EXP_DEVCAP2_OBFF_MASK 0x000c0000 /* OBFF support mechanism */
#define PCI_EXP_DEVCAP2_OBFF_MSG 0x00040000 /* New message signaling */
#define PCI_EXP_DEVCAP2_OBFF_WAKE 0x00080000 /* Re-use WAKE# for OBFF */
@@ -661,6 +663,7 @@
#define PCI_EXP_DEVCTL2_IDO_REQ_EN 0x0100 /* Allow IDO for requests */
#define PCI_EXP_DEVCTL2_IDO_CMP_EN 0x0200 /* Allow IDO for completions */
#define PCI_EXP_DEVCTL2_LTR_EN 0x0400 /* Enable LTR mechanism */
+#define PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN 0x1000 /* 10-Bit Tag Requester Enable */
#define PCI_EXP_DEVCTL2_OBFF_MSGA_EN 0x2000 /* Enable OBFF Message type A */
#define PCI_EXP_DEVCTL2_OBFF_MSGB_EN 0x4000 /* Enable OBFF Message type B */
#define PCI_EXP_DEVCTL2_OBFF_WAKE_EN 0x6000 /* OBFF using WAKE# signaling */
@@ -931,6 +934,7 @@
/* Single Root I/O Virtualization */
#define PCI_SRIOV_CAP 0x04 /* SR-IOV Capabilities */
#define PCI_SRIOV_CAP_VFM 0x00000001 /* VF Migration Capable */
+#define PCI_SRIOV_CAP_VF_10BIT_TAG_REQ 0x00000004 /* VF 10-Bit Tag Requester Supported */
#define PCI_SRIOV_CAP_INTR(x) ((x) >> 21) /* Interrupt Message Number */
#define PCI_SRIOV_CTRL 0x08 /* SR-IOV Control */
#define PCI_SRIOV_CTRL_VFE 0x0001 /* VF Enable */
@@ -938,6 +942,7 @@
#define PCI_SRIOV_CTRL_INTR 0x0004 /* VF Migration Interrupt Enable */
#define PCI_SRIOV_CTRL_MSE 0x0008 /* VF Memory Space Enable */
#define PCI_SRIOV_CTRL_ARI 0x0010 /* ARI Capable Hierarchy */
+#define PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN 0x0020 /* VF 10-Bit Tag Requester Enable */
#define PCI_SRIOV_STATUS 0x0a /* SR-IOV Status */
#define PCI_SRIOV_STATUS_VFM 0x0001 /* VF Migration Status */
#define PCI_SRIOV_INITIAL_VF 0x0c /* Initial VFs */
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 4/8] PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
` (2 preceding siblings ...)
2021-08-18 13:01 ` [PATCH V8 3/8] PCI: Add 10-Bit Tag register definitions Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 5/8] PCI/IOV: Add 10-Bit Tag sysfs files for VF devices Dongdong Liu
` (3 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
PCIe spec 5.0 r1.0 section 2.2.6.2 says:
If an Endpoint supports sending Requests to other Endpoints (as
opposed to host memory), the Endpoint must not send 10-Bit Tag
Requests to another given Endpoint unless an implementation-specific
mechanism determines that the Endpoint supports 10-Bit Tag Completer
capability.
Add a 10bit_tag sysfs file, write 0 to disable 10-Bit Tag Requester
when the driver does not bind the deivce. The typical use case is for
p2pdma when the peer device does not support 10-Bit Tag Completer.
Write 1 to enable 10-Bit Tag Requester when RC supports 10-Bit Tag
Completer capability. The typical use case is for host memory targeted
by DMA Requests. The 10bit_tag file content indicate current status of
10-Bit Tag Requester Enable.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
Documentation/ABI/testing/sysfs-bus-pci | 18 +++++++-
drivers/pci/pci-sysfs.c | 76 +++++++++++++++++++++++++++++++++
drivers/pci/pci.h | 2 +
drivers/pci/probe.c | 14 ++++++
4 files changed, 109 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 793cbb7..759682f 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -139,7 +139,7 @@ Description:
binary file containing the Vital Product Data for the
device. It should follow the VPD format defined in
PCI Specification 2.1 or 2.2, but users should consider
- that some devices may have incorrectly formatted data.
+ that some devices may have incorrectly formatted data.
If the underlying VPD has a writable section then the
corresponding section of this file will be writable.
@@ -407,3 +407,19 @@ Description:
The file is writable if the PF is bound to a driver that
implements ->sriov_set_msix_vec_count().
+
+What: /sys/bus/pci/devices/.../10bit_tag
+Date: August 2021
+Contact: Dongdong Liu <liudongdong3@huawei.com>
+Description:
+ The file will be visible when the device supports 10-Bit Tag
+ Requester. The file is readable, the value indicate current
+ status of 10-Bit Tag Requester Enable.
+ 1 - enabled, 0 - disabled.
+
+ The file is also writable, write 0 to disable 10-Bit Tag
+ Requester when the driver does not bind the device. The typical
+ use case is for p2pdma when the peer device does not support
+ 10-Bit Tag Completer. Write 1 to enable 10-Bit Tag Requester
+ when RC supports 10-Bit Tag Completer capability. The typical
+ use case is for host memory targeted by DMA Requests.
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 5d63df7..52d0757 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -306,6 +306,53 @@ static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR_RW(enable);
+static ssize_t pci_10bit_tag_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ bool enable;
+
+ if (kstrtobool(buf, &enable) < 0)
+ return -EINVAL;
+
+ if (pdev->driver)
+ return -EBUSY;
+
+ if (enable) {
+ if (!pcie_rp_10bit_tag_cmp_supported(pdev))
+ return -EPERM;
+
+ pcie_capability_set_word(pdev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+ } else {
+ pcie_capability_clear_word(pdev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+ }
+
+ return count;
+}
+
+static ssize_t pci_10bit_tag_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ u16 ctl;
+ int ret;
+
+ ret = pcie_capability_read_word(pdev, PCI_EXP_DEVCTL2, &ctl);
+ if (ret)
+ return -EINVAL;
+
+ return sysfs_emit(buf, "%u\n",
+ !!(ctl & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN));
+}
+
+static struct device_attribute dev_attr_10bit_tag = __ATTR(10bit_tag, 0644,
+ pci_10bit_tag_show,
+ pci_10bit_tag_store);
+
#ifdef CONFIG_NUMA
static ssize_t numa_node_store(struct device *dev,
struct device_attribute *attr, const char *buf,
@@ -635,6 +682,11 @@ static struct attribute *pcie_dev_attrs[] = {
NULL,
};
+static struct attribute *pcie_dev_10bit_tag_attrs[] = {
+ &dev_attr_10bit_tag.attr,
+ NULL,
+};
+
static struct attribute *pcibus_attrs[] = {
&dev_attr_bus_rescan.attr,
&dev_attr_cpuaffinity.attr,
@@ -1482,6 +1534,24 @@ static umode_t pcie_dev_attrs_are_visible(struct kobject *kobj,
return 0;
}
+static umode_t pcie_dev_10bit_tag_attrs_are_visible(struct kobject *kobj,
+ struct attribute *a, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct pci_dev *pdev = to_pci_dev(dev);
+
+ if (pdev->is_virtfn)
+ return 0;
+
+ if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ENDPOINT)
+ return 0;
+
+ if (!(pdev->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_REQ))
+ return 0;
+
+ return a->mode;
+}
+
static const struct attribute_group pci_dev_group = {
.attrs = pci_dev_attrs,
};
@@ -1521,6 +1591,11 @@ static const struct attribute_group pcie_dev_attr_group = {
.is_visible = pcie_dev_attrs_are_visible,
};
+static const struct attribute_group pcie_dev_10bit_tag_attr_group = {
+ .attrs = pcie_dev_10bit_tag_attrs,
+ .is_visible = pcie_dev_10bit_tag_attrs_are_visible,
+};
+
static const struct attribute_group *pci_dev_attr_groups[] = {
&pci_dev_attr_group,
&pci_dev_hp_attr_group,
@@ -1530,6 +1605,7 @@ static const struct attribute_group *pci_dev_attr_groups[] = {
#endif
&pci_bridge_attr_group,
&pcie_dev_attr_group,
+ &pcie_dev_10bit_tag_attr_group,
#ifdef CONFIG_PCIEAER
&aer_stats_attr_group,
#endif
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 93dcdd4..dca5aaf 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -244,6 +244,8 @@ struct device *pci_get_host_bridge_device(struct pci_dev *dev);
void pci_put_host_bridge_device(struct device *dev);
int pci_configure_extended_tags(struct pci_dev *dev, void *ign);
+bool pcie_rp_10bit_tag_cmp_supported(struct pci_dev *dev);
+
bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,
int crs_timeout);
bool pci_bus_generic_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *pl,
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c83245b..f9bc562 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2029,6 +2029,20 @@ static void pci_configure_mps(struct pci_dev *dev)
p_mps, mps, mpss);
}
+bool pcie_rp_10bit_tag_cmp_supported(struct pci_dev *dev)
+{
+ struct pci_dev *root;
+
+ root = pcie_find_root_port(dev);
+ if (!root)
+ return false;
+
+ if (!(root->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP))
+ return false;
+
+ return true;
+}
+
int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
{
struct pci_host_bridge *host;
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 5/8] PCI/IOV: Add 10-Bit Tag sysfs files for VF devices
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
` (3 preceding siblings ...)
2021-08-18 13:01 ` [PATCH V8 4/8] PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA Dongdong Liu
` (2 subsequent siblings)
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
PCIe spec 5.0 r1.0 section 2.2.6.2 says:
If an Endpoint supports sending Requests to other Endpoints (as
opposed to host memory), the Endpoint must not send 10-Bit Tag
Requests to another given Endpoint unless an implementation-specific
mechanism determines that the Endpoint supports 10-Bit Tag Completer
capability.
Add sriov_vf_10bit_tag file to query the status of VF 10-Bit Tag
Requester Enable.
Add a sriov_vf_10bit_tag_ctl sysfs file, write 0 to disable the VF
10-Bit Tag Requester. The typical use case is for p2pdma when the peer
device does not support 10-Bit Tag Completer. Write 1 to enable 10-Bit
Tag Requester when RC supports 10-Bit Tag Completer capability. The
typical use case is for host memory targeted by DMA Requests.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
Documentation/ABI/testing/sysfs-bus-pci | 23 ++++++++++++++
drivers/pci/iov.c | 54 +++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 759682f..692bf65 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -423,3 +423,26 @@ Description:
10-Bit Tag Completer. Write 1 to enable 10-Bit Tag Requester
when RC supports 10-Bit Tag Completer capability. The typical
use case is for host memory targeted by DMA Requests.
+
+What: /sys/bus/pci/devices/.../sriov_vf_10bit_tag
+Date: August 2021
+Contact: Dongdong Liu <liudongdong3@huawei.com>
+Description:
+ This file is associated with a SR-IOV physical function (PF).
+ It is visible when the device supports VF 10-Bit Tag Requester.
+ It contains the status of VF 10-Bit Tag Requester Enable.
+ The file is read-only.
+
+What: /sys/bus/pci/devices/.../sriov_vf_10bit_tag_ctl
+Date: August 2021
+Contact: Dongdong Liu <liudongdong3@huawei.com>
+Description:
+ This file is associated with a SR-IOV virtual function (VF).
+ It is visible when the device supports VF 10-Bit Tag
+ Requester. The file is only writeable when the VF driver
+ does not bind to a device. Write 0 to any VF's file disables
+ 10-Bit Tag Requester for all VFs. The typical use case is for
+ p2pdma when the peer device does not support 10-Bit Tag
+ Completer. Write 1 to enable 10-Bit Tag Requester for all VFs
+ when RC supports 10-Bit Tag Completer capability. The typical
+ use case is for host memory targeted by DMA Requests.
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index dafdc65..bf15b33 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -220,10 +220,42 @@ static ssize_t sriov_vf_msix_count_store(struct device *dev,
static DEVICE_ATTR_WO(sriov_vf_msix_count);
#endif
+
+static ssize_t sriov_vf_10bit_tag_ctl_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct pci_dev *vf_dev = to_pci_dev(dev);
+ struct pci_dev *pdev = pci_physfn(vf_dev);
+ bool enable;
+
+ if (kstrtobool(buf, &enable) < 0)
+ return -EINVAL;
+
+ if (vf_dev->driver)
+ return -EBUSY;
+
+ if (enable) {
+ if (!pcie_rp_10bit_tag_cmp_supported(pdev))
+ return -EPERM;
+
+ pdev->sriov->ctrl |= PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
+ } else {
+ pdev->sriov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
+ }
+
+ pci_write_config_word(pdev, pdev->sriov->pos + PCI_SRIOV_CTRL,
+ pdev->sriov->ctrl);
+
+ return count;
+}
+static DEVICE_ATTR_WO(sriov_vf_10bit_tag_ctl);
+
static struct attribute *sriov_vf_dev_attrs[] = {
#ifdef CONFIG_PCI_MSI
&dev_attr_sriov_vf_msix_count.attr,
#endif
+ &dev_attr_sriov_vf_10bit_tag_ctl.attr,
NULL,
};
@@ -236,6 +268,11 @@ static umode_t sriov_vf_attrs_are_visible(struct kobject *kobj,
if (!pdev->is_virtfn)
return 0;
+ pdev = pci_physfn(pdev);
+ if ((a == &dev_attr_sriov_vf_10bit_tag_ctl.attr) &&
+ !(pdev->sriov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ))
+ return 0;
+
return a->mode;
}
@@ -487,12 +524,23 @@ static ssize_t sriov_drivers_autoprobe_store(struct device *dev,
return count;
}
+static ssize_t sriov_vf_10bit_tag_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+
+ return sysfs_emit(buf, "%u\n",
+ !!(pdev->sriov->ctrl & PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN));
+}
+
static DEVICE_ATTR_RO(sriov_totalvfs);
static DEVICE_ATTR_RW(sriov_numvfs);
static DEVICE_ATTR_RO(sriov_offset);
static DEVICE_ATTR_RO(sriov_stride);
static DEVICE_ATTR_RO(sriov_vf_device);
static DEVICE_ATTR_RW(sriov_drivers_autoprobe);
+static DEVICE_ATTR_RO(sriov_vf_10bit_tag);
static struct attribute *sriov_pf_dev_attrs[] = {
&dev_attr_sriov_totalvfs.attr,
@@ -501,6 +549,7 @@ static struct attribute *sriov_pf_dev_attrs[] = {
&dev_attr_sriov_stride.attr,
&dev_attr_sriov_vf_device.attr,
&dev_attr_sriov_drivers_autoprobe.attr,
+ &dev_attr_sriov_vf_10bit_tag.attr,
#ifdef CONFIG_PCI_MSI
&dev_attr_sriov_vf_total_msix.attr,
#endif
@@ -511,10 +560,15 @@ static umode_t sriov_pf_attrs_are_visible(struct kobject *kobj,
struct attribute *a, int n)
{
struct device *dev = kobj_to_dev(kobj);
+ struct pci_dev *pdev = to_pci_dev(dev);
if (!dev_is_pf(dev))
return 0;
+ if ((a == &dev_attr_sriov_vf_10bit_tag.attr) &&
+ !(pdev->sriov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ))
+ return 0;
+
return a->mode;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
` (4 preceding siblings ...)
2021-08-18 13:01 ` [PATCH V8 5/8] PCI/IOV: Add 10-Bit Tag sysfs files for VF devices Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 16:07 ` Logan Gunthorpe
2021-08-18 13:01 ` [PATCH V8 7/8] PCI: Enable 10-Bit Tag support for PCIe Endpoint device Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 8/8] PCI/IOV: Enable 10-Bit Tag support for PCIe VF devices Dongdong Liu
7 siblings, 1 reply; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
Add a 10-Bit Tag check in the P2PDMA code to ensure that a device with
10-Bit Tag Requester doesn't interact with a device that does not
support 10-Bit Tag Completer. Before that happens, the kernel should
emit a warning.
"echo 0 > /sys/bus/pci/devices/.../10bit_tag" to disable 10-Bit Tag
Requester for PF device.
"echo 0 > /sys/bus/pci/devices/.../sriov_vf_10bit_tag_ctl" to disable
10-Bit Tag Requester for VF device.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
drivers/pci/p2pdma.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 50cdde3..2b9c2c9 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -19,6 +19,7 @@
#include <linux/random.h>
#include <linux/seq_buf.h>
#include <linux/xarray.h>
+#include "pci.h"
enum pci_p2pdma_map_type {
PCI_P2PDMA_MAP_UNKNOWN = 0,
@@ -410,6 +411,50 @@ static unsigned long map_types_idx(struct pci_dev *client)
(client->bus->number << 8) | client->devfn;
}
+static bool pci_10bit_tags_unsupported(struct pci_dev *a,
+ struct pci_dev *b,
+ bool verbose)
+{
+ bool req;
+ bool comp;
+ u16 ctl;
+ const char *str = "10bit_tag";
+
+ if (a->is_virtfn) {
+#ifdef CONFIG_PCI_IOV
+ req = !!(a->physfn->sriov->ctrl &
+ PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN);
+#endif
+ } else {
+ pcie_capability_read_word(a, PCI_EXP_DEVCTL2, &ctl);
+ req = !!(ctl & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+ }
+
+ comp = !!(b->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP);
+
+ /* 10-bit tags not enabled on requester */
+ if (!req)
+ return false;
+
+ /* Completer can handle anything */
+ if (comp)
+ return false;
+
+ if (!verbose)
+ return true;
+
+ pci_warn(a, "cannot be used for peer-to-peer DMA as 10-Bit Tag Requester enable is set for this device, but peer device (%s) does not support the 10-Bit Tag Completer\n",
+ pci_name(b));
+
+ if (a->is_virtfn)
+ str = "sriov_vf_10bit_tag_ctl";
+
+ pci_warn(a, "to disable 10-Bit Tag Requester for this device, echo 0 > /sys/bus/pci/devices/%s/%s\n",
+ pci_name(a), str);
+
+ return true;
+}
+
/*
* Calculate the P2PDMA mapping type and distance between two PCI devices.
*
@@ -532,6 +577,9 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
}
done:
+ if (pci_10bit_tags_unsupported(client, provider, verbose))
+ map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
+
rcu_read_lock();
p2pdma = rcu_dereference(provider->p2pdma);
if (p2pdma)
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 7/8] PCI: Enable 10-Bit Tag support for PCIe Endpoint device
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
` (5 preceding siblings ...)
2021-08-18 13:01 ` [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 8/8] PCI/IOV: Enable 10-Bit Tag support for PCIe VF devices Dongdong Liu
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
10-Bit Tag capability, introduced in PCIe-4.0 increases the total Tag
field size from 8 bits to 10 bits.
PCIe spec 5.0 r1.0 section 2.2.6.2 "Considerations for Implementing
10-Bit Tag Capabilities" Implementation Note:
For platforms where the RC supports 10-Bit Tag Completer capability,
it is highly recommended for platform firmware or operating software
that configures PCIe hierarchies to Set the 10-Bit Tag Requester Enable
bit automatically in Endpoints with 10-Bit Tag Requester capability.
This enables the important class of 10-Bit Tag capable adapters that
send Memory Read Requests only to host memory.
It's safe to enable 10-bit tags for all devices below a Root Port that
supports them. Switches that lack 10-Bit Tag Completer capability are
still able to forward NPRs and Completions carrying 10-Bit Tags correctly,
since the two new Tag bits are in TLP Header bits that were formerly
Reserved.
PCIe spec 5.0 r1.0 section 2.2.6.2 says:
If an Endpoint supports sending Requests to other Endpoints (as opposed
to host memory), the Endpoint must not send 10-Bit Tag Requests to
another given Endpoint unless an implementation-specific mechanism
determines that the Endpoint supports 10-Bit Tag Completer capability.
It is not safe for P2P traffic if an Endpoint send 10-Bit Tag Requesters
to another Endpoint that does not support 10-Bit Tag Completer capability,
so we provide sysfs file to disable 10-Bit Tag Requester. Unbind the
device driver, set the sysfs file and then rebind the driver.
Add a kernel parameter pcie_tag_peer2peer that disables 10-Bit Tag
Requester for all PCIe devices. This configuration allows peer-to-peer
DMA between any pair of devices, possibly at the cost of reduced
performance.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
Documentation/admin-guide/kernel-parameters.txt | 5 +++
drivers/pci/iov.c | 3 ++
drivers/pci/pci-sysfs.c | 3 ++
drivers/pci/pci.c | 4 +++
drivers/pci/pci.h | 8 +++++
drivers/pci/probe.c | 46 ++++++++++++++++++++++++-
6 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index bdb2200..ebcda18 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3948,6 +3948,11 @@
any pair of devices, possibly at the cost of
reduced performance. This also guarantees
that hot-added devices will work.
+ pcie_tag_peer2peer Disable 10-Bit Tag Requester for all
+ PCIe devices. This configuration allows
+ peer-to-peer DMA between any pair of devices,
+ possibly at the cost of reduced performance.
+
cbiosize=nn[KMG] The fixed amount of bus space which is
reserved for the CardBus bridge's IO window.
The default value is 256 bytes.
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index bf15b33..757e77d 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -235,6 +235,9 @@ static ssize_t sriov_vf_10bit_tag_ctl_store(struct device *dev,
if (vf_dev->driver)
return -EBUSY;
+ if (pcie_tag_config == PCIE_TAG_PEER2PEER)
+ return -EPERM;
+
if (enable) {
if (!pcie_rp_10bit_tag_cmp_supported(pdev))
return -EPERM;
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 52d0757..5bc1970 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -319,6 +319,9 @@ static ssize_t pci_10bit_tag_store(struct device *dev,
if (pdev->driver)
return -EBUSY;
+ if (pcie_tag_config == PCIE_TAG_PEER2PEER)
+ return -EPERM;
+
if (enable) {
if (!pcie_rp_10bit_tag_cmp_supported(pdev))
return -EPERM;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d14c573..e6c6bce 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -112,6 +112,8 @@ enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_PEER2PEER;
enum pcie_bus_config_types pcie_bus_config = PCIE_BUS_DEFAULT;
#endif
+enum pcie_tag_config_types pcie_tag_config = PCIE_TAG_DEFAULT;
+
/*
* The default CLS is used if arch didn't set CLS explicitly and not
* all pci devices agree on the same value. Arch can override either
@@ -6643,6 +6645,8 @@ static int __init pci_setup(char *str)
pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
} else if (!strncmp(str, "disable_acs_redir=", 18)) {
disable_acs_redir_param = str + 18;
+ } else if (!strncmp(str, "pcie_tag_peer2peer", 18)) {
+ pcie_tag_config = PCIE_TAG_PEER2PEER;
} else {
pr_err("PCI: Unknown option `%s'\n", str);
}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index dca5aaf..e9b5875 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -37,6 +37,14 @@ int pci_probe_reset_function(struct pci_dev *dev);
int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
int pci_bus_error_reset(struct pci_dev *dev);
+enum pcie_tag_config_types {
+ PCIE_TAG_DEFAULT, /* Enable 10-Bit Tag Requester for devices below
+ Root Port that support 10-Bit Tag Completer. */
+ PCIE_TAG_PEER2PEER /* Disable 10-Bit Tag Requester for all devices. */
+};
+
+extern enum pcie_tag_config_types pcie_tag_config;
+
#define PCI_PM_D2_DELAY 200 /* usec; see PCIe r4.0, sec 5.9.1 */
#define PCI_PM_D3HOT_WAIT 10 /* msec */
#define PCI_PM_D3COLD_WAIT 100 /* msec */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f9bc562..49f16d5 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2043,10 +2043,30 @@ bool pcie_rp_10bit_tag_cmp_supported(struct pci_dev *dev)
return true;
}
+static void pci_configure_10bit_tags(struct pci_dev *dev)
+{
+ /*
+ * PCIe 5.0 section 9.3.5.10 10-Bit Tag Requester Enable in Device
+ * Control 2 Register is RsvdP for VF.
+ */
+ if (dev->is_virtfn)
+ return;
+
+ if (!pcie_rp_10bit_tag_cmp_supported(dev))
+ return;
+
+ if (pci_pcie_type(dev) != PCI_EXP_TYPE_ENDPOINT)
+ return;
+
+ pci_dbg(dev, "enabling 10-Bit Tag Requester\n");
+ pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+}
+
int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
{
struct pci_host_bridge *host;
- u16 ctl;
+ u16 ctl, ctl2;
int ret;
if (!pci_is_pcie(dev))
@@ -2059,6 +2079,10 @@ int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
if (ret)
return 0;
+ ret = pcie_capability_read_word(dev, PCI_EXP_DEVCTL2, &ctl2);
+ if (ret)
+ return 0;
+
host = pci_find_host_bridge(dev->bus);
if (!host)
return 0;
@@ -2073,6 +2097,12 @@ int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
pcie_capability_clear_word(dev, PCI_EXP_DEVCTL,
PCI_EXP_DEVCTL_EXT_TAG);
}
+
+ if (ctl2 & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN) {
+ pci_info(dev, "disabling 10-Bit Tags\n");
+ pcie_capability_clear_word(dev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+ }
return 0;
}
@@ -2081,6 +2111,20 @@ int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
pcie_capability_set_word(dev, PCI_EXP_DEVCTL,
PCI_EXP_DEVCTL_EXT_TAG);
}
+
+ if ((pcie_tag_config == PCIE_TAG_PEER2PEER) &&
+ (ctl2 & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN)) {
+ pci_info(dev, "disabling 10-Bit Tags\n");
+ pcie_capability_clear_word(dev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
+ return 0;
+ }
+
+ if (pcie_tag_config != PCIE_TAG_DEFAULT)
+ return 0;
+
+ pci_configure_10bit_tags(dev);
+
return 0;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH V8 8/8] PCI/IOV: Enable 10-Bit Tag support for PCIe VF devices
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
` (6 preceding siblings ...)
2021-08-18 13:01 ` [PATCH V8 7/8] PCI: Enable 10-Bit Tag support for PCIe Endpoint device Dongdong Liu
@ 2021-08-18 13:01 ` Dongdong Liu
7 siblings, 0 replies; 10+ messages in thread
From: Dongdong Liu @ 2021-08-18 13:01 UTC (permalink / raw)
To: helgaas, hch, kw, logang, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
Enable 10-Bit Tag Requester for the VF devices below the
Root Port that support 10-Bit Tag Completer.
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
---
drivers/pci/iov.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 757e77d..1c40baf 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -691,6 +691,15 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
pci_iov_set_numvfs(dev, nr_virtfn);
iov->ctrl |= PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE;
+
+ if ((pcie_tag_config == PCIE_TAG_DEFAULT) &&
+ (iov->cap & PCI_SRIOV_CAP_VF_10BIT_TAG_REQ) &&
+ pcie_rp_10bit_tag_cmp_supported(dev))
+ iov->ctrl |= PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
+
+ if (pcie_tag_config == PCIE_TAG_PEER2PEER)
+ iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
+
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
msleep(100);
@@ -707,6 +716,7 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
err_pcibios:
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
+ iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
@@ -739,6 +749,7 @@ static void sriov_disable(struct pci_dev *dev)
sriov_del_vfs(dev);
iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
+ iov->ctrl &= ~PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN;
pci_cfg_access_lock(dev);
pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
ssleep(1);
--
2.7.4
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA
2021-08-18 13:01 ` [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA Dongdong Liu
@ 2021-08-18 16:07 ` Logan Gunthorpe
0 siblings, 0 replies; 10+ messages in thread
From: Logan Gunthorpe @ 2021-08-18 16:07 UTC (permalink / raw)
To: Dongdong Liu, helgaas, hch, kw, leon, linux-pci, rajur, hverkuil-cisco
Cc: linux-media, netdev
On 2021-08-18 7:01 a.m., Dongdong Liu wrote:
> Add a 10-Bit Tag check in the P2PDMA code to ensure that a device with
> 10-Bit Tag Requester doesn't interact with a device that does not
> support 10-Bit Tag Completer. Before that happens, the kernel should
> emit a warning.
>
> "echo 0 > /sys/bus/pci/devices/.../10bit_tag" to disable 10-Bit Tag
> Requester for PF device.
>
> "echo 0 > /sys/bus/pci/devices/.../sriov_vf_10bit_tag_ctl" to disable
> 10-Bit Tag Requester for VF device.
>
> Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Looks good to me, thanks.
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
> ---
> drivers/pci/p2pdma.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 48 insertions(+)
>
> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
> index 50cdde3..2b9c2c9 100644
> --- a/drivers/pci/p2pdma.c
> +++ b/drivers/pci/p2pdma.c
> @@ -19,6 +19,7 @@
> #include <linux/random.h>
> #include <linux/seq_buf.h>
> #include <linux/xarray.h>
> +#include "pci.h"
>
> enum pci_p2pdma_map_type {
> PCI_P2PDMA_MAP_UNKNOWN = 0,
> @@ -410,6 +411,50 @@ static unsigned long map_types_idx(struct pci_dev *client)
> (client->bus->number << 8) | client->devfn;
> }
>
> +static bool pci_10bit_tags_unsupported(struct pci_dev *a,
> + struct pci_dev *b,
> + bool verbose)
> +{
> + bool req;
> + bool comp;
> + u16 ctl;
> + const char *str = "10bit_tag";
> +
> + if (a->is_virtfn) {
> +#ifdef CONFIG_PCI_IOV
> + req = !!(a->physfn->sriov->ctrl &
> + PCI_SRIOV_CTRL_VF_10BIT_TAG_REQ_EN);
> +#endif
> + } else {
> + pcie_capability_read_word(a, PCI_EXP_DEVCTL2, &ctl);
> + req = !!(ctl & PCI_EXP_DEVCTL2_10BIT_TAG_REQ_EN);
> + }
> +
> + comp = !!(b->pcie_devcap2 & PCI_EXP_DEVCAP2_10BIT_TAG_COMP);
> +
> + /* 10-bit tags not enabled on requester */
> + if (!req)
> + return false;
> +
> + /* Completer can handle anything */
> + if (comp)
> + return false;
> +
> + if (!verbose)
> + return true;
> +
> + pci_warn(a, "cannot be used for peer-to-peer DMA as 10-Bit Tag Requester enable is set for this device, but peer device (%s) does not support the 10-Bit Tag Completer\n",
> + pci_name(b));
> +
> + if (a->is_virtfn)
> + str = "sriov_vf_10bit_tag_ctl";
> +
> + pci_warn(a, "to disable 10-Bit Tag Requester for this device, echo 0 > /sys/bus/pci/devices/%s/%s\n",
> + pci_name(a), str);
> +
> + return true;
> +}
> +
> /*
> * Calculate the P2PDMA mapping type and distance between two PCI devices.
> *
> @@ -532,6 +577,9 @@ calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
> map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
> }
> done:
> + if (pci_10bit_tags_unsupported(client, provider, verbose))
> + map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
> +
> rcu_read_lock();
> p2pdma = rcu_dereference(provider->p2pdma);
> if (p2pdma)
>
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2021-08-18 16:07 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-18 13:01 [PATCH V8 0/8] PCI: Enable 10-Bit tag support for PCIe devices Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 1/8] PCI: Use cached Device Capabilities Register Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 2/8] PCI: Use cached Device Capabilities 2 Register Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 3/8] PCI: Add 10-Bit Tag register definitions Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 4/8] PCI/sysfs: Add a 10-Bit Tag sysfs file PCIe Endpoint devices Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 5/8] PCI/IOV: Add 10-Bit Tag sysfs files for VF devices Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 6/8] PCI/P2PDMA: Add a 10-Bit Tag check in P2PDMA Dongdong Liu
2021-08-18 16:07 ` Logan Gunthorpe
2021-08-18 13:01 ` [PATCH V8 7/8] PCI: Enable 10-Bit Tag support for PCIe Endpoint device Dongdong Liu
2021-08-18 13:01 ` [PATCH V8 8/8] PCI/IOV: Enable 10-Bit Tag support for PCIe VF devices Dongdong Liu
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