[PATCH v2 0/3] PCI endpoint additional pci_epc_set_bar() checks

[PATCH v2 0/3] PCI endpoint additional pci_epc_set_bar() checks

[Niklas Cassel]

Hello all,

This series adds some extra checks to ensure that it is not possible to
program the iATU with an address which we did not intend to use.

If these checks were in place when testing some of the earlier revisions
of Frank's doorbell patches (which did not handle fixed BARs properly),
we would gotten an error, rather than silently using an address which we
did not intend to use.

Having these checks in place will hopefully avoid similar debugging in the
future.


Kind regards,
Niklas

Niklas Cassel (3):
  PCI: artpec6: Implement dw_pcie_ep operation get_features
  PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()
  PCI: dwc: ep: Add 'address' alignment to 'size' check in
    dw_pcie_prog_ep_inbound_atu()

 drivers/pci/controller/dwc/pcie-artpec6.c       | 13 +++++++++++++
 drivers/pci/controller/dwc/pcie-designware-ep.c |  8 +++++---
 drivers/pci/controller/dwc/pcie-designware.c    |  5 +++--
 drivers/pci/controller/dwc/pcie-designware.h    |  2 +-
 drivers/pci/endpoint/pci-epc-core.c             | 11 +++++++++--
 5 files changed, 31 insertions(+), 8 deletions(-)

-- 
2.47.0

[PATCH v2 1/3] PCI: artpec6: Implement dw_pcie_ep operation get_features

[Niklas Cassel]

All non-DWC EPC drivers implement (struct pci_epc *)->ops->get_features().
All DWC EPC drivers implement (struct dw_pcie_ep *)->ops->get_features(),
except for pcie-artpec6.c.

epc_features has been required in pci-epf-test.c since commit 6613bc2301ba
("PCI: endpoint: Fix NULL pointer dereference for ->get_features()").

A follow-up commit will make further use of epc_features in EPC core code.

Implement epc_features in the only EPC driver where it is currently not
implemented.

Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/controller/dwc/pcie-artpec6.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-artpec6.c b/drivers/pci/controller/dwc/pcie-artpec6.c
index f8e7283dacd47..234c8cbcae3af 100644
--- a/drivers/pci/controller/dwc/pcie-artpec6.c
+++ b/drivers/pci/controller/dwc/pcie-artpec6.c
@@ -369,9 +369,22 @@ static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
 	return 0;
 }
 
+static const struct pci_epc_features artpec6_pcie_epc_features = {
+	.linkup_notifier = false,
+	.msi_capable = true,
+	.msix_capable = false,
+};
+
+static const struct pci_epc_features *
+artpec6_pcie_get_features(struct dw_pcie_ep *ep)
+{
+	return &artpec6_pcie_epc_features;
+}
+
 static const struct dw_pcie_ep_ops pcie_ep_ops = {
 	.init = artpec6_pcie_ep_init,
 	.raise_irq = artpec6_pcie_raise_irq,
+	.get_features = artpec6_pcie_get_features,
 };
 
 static int artpec6_pcie_probe(struct platform_device *pdev)
-- 
2.47.0

Re: [PATCH v2 1/3] PCI: artpec6: Implement dw_pcie_ep operation get_features

[Jesper Nilsson]

On Fri, Nov 15, 2024 at 09:47:50AM +0100, Niklas Cassel wrote:
> All non-DWC EPC drivers implement (struct pci_epc *)->ops->get_features().
> All DWC EPC drivers implement (struct dw_pcie_ep *)->ops->get_features(),
> except for pcie-artpec6.c.
> 
> epc_features has been required in pci-epf-test.c since commit 6613bc2301ba
> ("PCI: endpoint: Fix NULL pointer dereference for ->get_features()").
> 
> A follow-up commit will make further use of epc_features in EPC core code.
> 
> Implement epc_features in the only EPC driver where it is currently not
> implemented.
> 
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>

For the ARTPEC-6 part:

Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com

[PATCH v2 2/3] PCI: endpoint: Add size check for fixed size BARs in pci_epc_set_bar()

[Niklas Cassel]

A BAR of type BAR_FIXED has a fixed BAR size (the size cannot be changed).

When using pci_epf_alloc_space() to allocate backing memory for a BAR,
pci_epf_alloc_space() will always set the size to the fixed BAR size if
the BAR type is BAR_FIXED (and will give an error if you the requested size
is larger than the fixed BAR size).

However, some drivers might not call pci_epf_alloc_space() before calling
pci_epc_set_bar(), so add a check in pci_epc_set_bar() to ensure that an
EPF driver cannot set a size different from the fixed BAR size, if the BAR
type is BAR_FIXED.

The pci_epc_function_is_valid() check is removed because this check is now
done by pci_epc_get_features().

Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/endpoint/pci-epc-core.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index bed7c7d1fe3c3..c69c133701c92 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -609,10 +609,17 @@ EXPORT_SYMBOL_GPL(pci_epc_clear_bar);
 int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 		    struct pci_epf_bar *epf_bar)
 {
-	int ret;
+	const struct pci_epc_features *epc_features;
+	enum pci_barno bar = epf_bar->barno;
 	int flags = epf_bar->flags;
+	int ret;
 
-	if (!pci_epc_function_is_valid(epc, func_no, vfunc_no))
+	epc_features = pci_epc_get_features(epc, func_no, vfunc_no);
+	if (!epc_features)
+		return -EINVAL;
+
+	if (epc_features->bar[bar].type == BAR_FIXED &&
+	    (epc_features->bar[bar].fixed_size != epf_bar->size))
 		return -EINVAL;
 
 	if ((epf_bar->barno == BAR_5 && flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ||
-- 
2.47.0

[PATCH v2 3/3] PCI: dwc: ep: Add 'address' alignment to 'size' check in dw_pcie_prog_ep_inbound_atu()

[Niklas Cassel]

dw_pcie_prog_ep_inbound_atu() is used to program an inbound iATU in
"BAR Match Mode".

A memory address returned by e.g. kmalloc() is guaranteed to have natural
alignment (aligned to the size of the allocation). It is however not
guaranteed that pci_epc_set_bar() (and thus dw_pcie_prog_ep_inbound_atu())
is supplied an address that has natural alignment. (An EPF driver can send
in an arbitrary physical address to pci_epc_set_bar().)

The DWC Databook description for the LWR_TARGET_RW and LWR_TARGET_HW fields
in the IATU_LWR_TARGET_ADDR_OFF_INBOUND_i registers state that:
"Field size depends on log2(BAR_MASK+1) in BAR match mode."

I.e. only the upper bits are writable, and the number of writable bits is
dependent on the configured BAR_MASK.

Add a check to ensure that the physical address programmed in the iATU is
aligned to the size of the BAR (BAR_MASK+1), as without this, we can get
hard to debug errors, as we could write to bits that are read-only (without
getting a write error), which could cause the iATU to end up redirecting to
a physical address that is different from the address that we intended.

Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c | 8 +++++---
 drivers/pci/controller/dwc/pcie-designware.c    | 5 +++--
 drivers/pci/controller/dwc/pcie-designware.h    | 2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 507e40bd18c8f..4ad6ebd2ea320 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -128,7 +128,8 @@ static int dw_pcie_ep_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 }
 
 static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
-				  dma_addr_t cpu_addr, enum pci_barno bar)
+				  dma_addr_t cpu_addr, enum pci_barno bar,
+				  size_t size)
 {
 	int ret;
 	u32 free_win;
@@ -145,7 +146,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
 	}
 
 	ret = dw_pcie_prog_ep_inbound_atu(pci, func_no, free_win, type,
-					  cpu_addr, bar);
+					  cpu_addr, bar, size);
 	if (ret < 0) {
 		dev_err(pci->dev, "Failed to program IB window\n");
 		return ret;
@@ -229,7 +230,8 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 	else
 		type = PCIE_ATU_TYPE_IO;
 
-	ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar);
+	ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar,
+				     size);
 	if (ret)
 		return ret;
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 6d6cbc8b5b2c6..3c683b6119c39 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -597,11 +597,12 @@ int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type,
 }
 
 int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,
-				int type, u64 cpu_addr, u8 bar)
+				int type, u64 cpu_addr, u8 bar, size_t size)
 {
 	u32 retries, val;
 
-	if (!IS_ALIGNED(cpu_addr, pci->region_align))
+	if (!IS_ALIGNED(cpu_addr, pci->region_align) ||
+	    !IS_ALIGNED(cpu_addr, size))
 		return -EINVAL;
 
 	dw_pcie_writel_atu_ib(pci, index, PCIE_ATU_LOWER_TARGET,
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 347ab74ac35aa..fc08727116725 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -491,7 +491,7 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
 int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type,
 			     u64 cpu_addr, u64 pci_addr, u64 size);
 int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,
-				int type, u64 cpu_addr, u8 bar);
+				int type, u64 cpu_addr, u8 bar, size_t size);
 void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index);
 void dw_pcie_setup(struct dw_pcie *pci);
 void dw_pcie_iatu_detect(struct dw_pcie *pci);
-- 
2.47.0

Re: [PATCH v2 0/3] PCI endpoint additional pci_epc_set_bar() checks

[Niklas Cassel]

On Fri, Nov 15, 2024 at 09:47:49AM +0100, Niklas Cassel wrote:
> Hello all,
> 
> This series adds some extra checks to ensure that it is not possible to
> program the iATU with an address which we did not intend to use.
> 
> If these checks were in place when testing some of the earlier revisions
> of Frank's doorbell patches (which did not handle fixed BARs properly),
> we would gotten an error, rather than silently using an address which we
> did not intend to use.
> 
> Having these checks in place will hopefully avoid similar debugging in the
> future.

Changes since v1:
-Improved commit message in patch 3/3.
-Picked up tags.


Kind regards,
Niklas