* [PATCH v5 1/6] PCI/IOV: Return unsigned int from pci_sriov_get_totalvfs()
[not found] <20260722073913.1807677-1-zhiw@nvidia.com>
@ 2026-07-22 7:39 ` Zhi Wang
2026-07-22 7:49 ` sashiko-bot
2026-07-22 7:39 ` [PATCH v5 2/6] rust: pci: add sriov_get_totalvfs() helper Zhi Wang
1 sibling, 1 reply; 5+ messages in thread
From: Zhi Wang @ 2026-07-22 7:39 UTC (permalink / raw)
To: dakr, acourbot
Cc: airlied, simona, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
lossin, a.hindborg, aliceryhl, tmgross, jhubbard, ecourtney,
joelagnelf, apopple, cjia, smitra, kjaju, alkumar, ankita,
aniketa, kwankhede, targupta, nova-gpu, linux-kernel, zhiwang,
Zhi Wang, Bjorn Helgaas, David Laight, linux-pci
pci_sriov_get_totalvfs() reports a VF count, not an errno-style
status. It returns 0 when SR-IOV is unavailable or the device is not a
PF, and otherwise returns the PF's driver_max_VFs value.
driver_max_VFs is stored as a u16 in struct pci_sriov. It is derived
from the SR-IOV TotalVFs field or from a driver-provided limit, so the
implementation cannot return a negative value.
Change the declaration, CONFIG_PCI_IOV stub, and implementation to
return unsigned int.
Suggested-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: linux-pci@vger.kernel.org
Link: https://lore.kernel.org/all/DJHPRE4TGGT8.BUTMYOF5YE05@nvidia.com/
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
drivers/pci/iov.c | 2 +-
include/linux/pci.h | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index b0d24839c084..9d408fb8ac25 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -1283,7 +1283,7 @@ EXPORT_SYMBOL_GPL(pci_sriov_set_totalvfs);
* SRIOV capability value of TotalVFs or the value of driver_max_VFs
* if the driver reduced it. Otherwise 0.
*/
-int pci_sriov_get_totalvfs(struct pci_dev *dev)
+unsigned int pci_sriov_get_totalvfs(struct pci_dev *dev)
{
if (!dev->is_physfn)
return 0;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index ebb5b9d76360..2b9c61de5f67 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2569,7 +2569,7 @@ void pci_iov_remove_virtfn(struct pci_dev *dev, int id);
int pci_num_vf(struct pci_dev *dev);
int pci_vfs_assigned(struct pci_dev *dev);
int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
-int pci_sriov_get_totalvfs(struct pci_dev *dev);
+unsigned int pci_sriov_get_totalvfs(struct pci_dev *dev);
int pci_sriov_configure_simple(struct pci_dev *dev, int nr_virtfn);
resource_size_t pci_iov_resource_size(const struct pci_dev *dev, int resno);
int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size);
@@ -2622,7 +2622,7 @@ static inline int pci_vfs_assigned(struct pci_dev *dev)
{ return 0; }
static inline int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs)
{ return 0; }
-static inline int pci_sriov_get_totalvfs(struct pci_dev *dev)
+static inline unsigned int pci_sriov_get_totalvfs(struct pci_dev *dev)
{ return 0; }
#define pci_sriov_configure_simple NULL
static inline resource_size_t pci_iov_resource_size(const struct pci_dev *dev,
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v5 2/6] rust: pci: add sriov_get_totalvfs() helper
[not found] <20260722073913.1807677-1-zhiw@nvidia.com>
2026-07-22 7:39 ` [PATCH v5 1/6] PCI/IOV: Return unsigned int from pci_sriov_get_totalvfs() Zhi Wang
@ 2026-07-22 7:39 ` Zhi Wang
2026-07-22 7:52 ` sashiko-bot
2026-07-23 5:30 ` Alexandre Courbot
1 sibling, 2 replies; 5+ messages in thread
From: Zhi Wang @ 2026-07-22 7:39 UTC (permalink / raw)
To: dakr, acourbot
Cc: airlied, simona, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
lossin, a.hindborg, aliceryhl, tmgross, jhubbard, ecourtney,
joelagnelf, apopple, cjia, smitra, kjaju, alkumar, ankita,
aniketa, kwankhede, targupta, nova-gpu, linux-kernel, zhiwang,
Zhi Wang, Bjorn Helgaas, David Laight, linux-pci
Expose pci_sriov_get_totalvfs() to Rust PCI drivers so they can query
how many SR-IOV VFs a device supports.
Use a conditional C helper because the !CONFIG_PCI_IOV version of
pci_sriov_get_totalvfs() is a static inline function and is therefore
not emitted into the Rust bindings. Return Option<NonZero<u16>> so Rust
callers must handle the zero value that represents unavailable SR-IOV.
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: linux-pci@vger.kernel.org
Link: https://lore.kernel.org/all/DJHPRE4TGGT8.BUTMYOF5YE05@nvidia.com/
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
---
rust/helpers/pci.c | 8 ++++++++
rust/kernel/pci.rs | 13 +++++++++++++
2 files changed, 21 insertions(+)
diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c
index e44905317d75..4ebf256dff23 100644
--- a/rust/helpers/pci.c
+++ b/rust/helpers/pci.c
@@ -24,6 +24,14 @@ __rust_helper bool rust_helper_dev_is_pci(const struct device *dev)
return dev_is_pci(dev);
}
+#ifndef CONFIG_PCI_IOV
+__rust_helper unsigned int
+rust_helper_pci_sriov_get_totalvfs(struct pci_dev *pdev)
+{
+ return pci_sriov_get_totalvfs(pdev);
+}
+#endif
+
#ifndef CONFIG_PCI_MSI
__rust_helper int rust_helper_pci_alloc_irq_vectors(struct pci_dev *dev,
unsigned int min_vecs,
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index c6d6bd8f251d..9f19ccd5905c 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -25,6 +25,7 @@
use core::{
marker::PhantomData,
mem::offset_of,
+ num::NonZero,
ptr::{
addr_of_mut,
NonNull, //
@@ -452,6 +453,18 @@ pub fn pci_class(&self) -> Class {
}
impl<'a> Device<device::Core<'a>> {
+ /// Returns the total number of VFs, or [`None`] if SR-IOV is not available.
+ #[inline]
+ pub fn sriov_get_totalvfs(&self) -> Option<NonZero<u16>> {
+ // SAFETY: `self.as_raw()` is a valid pointer to a `struct pci_dev`.
+ let total_vfs = unsafe { bindings::pci_sriov_get_totalvfs(self.as_raw()) };
+
+ // CAST: The C function returns `unsigned int`, but the value originates
+ // from TotalVFs/driver_max_VFs (which are defined as `u16`), so this cast
+ // cannot truncate.
+ NonZero::new(total_vfs as u16)
+ }
+
/// Enable memory resources for this device.
pub fn enable_device_mem(&self) -> Result {
// SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`.
--
2.53.0
^ permalink raw reply related [flat|nested] 5+ messages in thread