[PATCH v3 1/5] PCI/IOV: Restore VF resizable BAR state after reset
From: Michał Winiarski
Date: Thu Oct 10 2024 - 06:33:17 EST
Similar to regular resizable BAR, VF BAR can also be resized, e.g. by
the system firmware, or the PCI subsystem itself.
Add the capability ID and restore it as a part of IOV state.
See PCIe r4.0, sec 9.3.7.4.
Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx>
---
drivers/pci/iov.c | 29 ++++++++++++++++++++++++++++-
include/uapi/linux/pci_regs.h | 1 +
2 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index aaa33e8dc4c97..fd5c059b29c13 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -7,6 +7,7 @@
* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@xxxxxxxxx>
*/
+#include <linux/bitfield.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/export.h>
@@ -862,6 +863,30 @@ static void sriov_release(struct pci_dev *dev)
dev->sriov = NULL;
}
+static void sriov_restore_vf_rebar_state(struct pci_dev *dev)
+{
+ unsigned int pos, nbars, i;
+ u32 ctrl;
+
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VF_REBAR);
+ if (!pos)
+ return;
+
+ pci_read_config_dword(dev, pos + PCI_REBAR_CTRL, &ctrl);
+ nbars = FIELD_GET(PCI_REBAR_CTRL_NBAR_MASK, ctrl);
+
+ for (i = 0; i < nbars; i++, pos += 8) {
+ int bar_idx, size;
+
+ pci_read_config_dword(dev, pos + PCI_REBAR_CTRL, &ctrl);
+ bar_idx = ctrl & PCI_REBAR_CTRL_BAR_IDX;
+ size = pci_rebar_bytes_to_size(dev->sriov->barsz[bar_idx]);
+ ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
+ ctrl |= FIELD_PREP(PCI_REBAR_CTRL_BAR_SIZE, size);
+ pci_write_config_dword(dev, pos + PCI_REBAR_CTRL, ctrl);
+ }
+}
+
static void sriov_restore_state(struct pci_dev *dev)
{
int i;
@@ -1021,8 +1046,10 @@ resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
*/
void pci_restore_iov_state(struct pci_dev *dev)
{
- if (dev->is_physfn)
+ if (dev->is_physfn) {
+ sriov_restore_vf_rebar_state(dev);
sriov_restore_state(dev);
+ }
}
/**
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 12323b3334a9c..a0cf701c4c3af 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -740,6 +740,7 @@
#define PCI_EXT_CAP_ID_L1SS 0x1E /* L1 PM Substates */
#define PCI_EXT_CAP_ID_PTM 0x1F /* Precision Time Measurement */
#define PCI_EXT_CAP_ID_DVSEC 0x23 /* Designated Vendor-Specific */
+#define PCI_EXT_CAP_ID_VF_REBAR 0x24 /* VF Resizable BAR */
#define PCI_EXT_CAP_ID_DLF 0x25 /* Data Link Feature */
#define PCI_EXT_CAP_ID_PL_16GT 0x26 /* Physical Layer 16.0 GT/s */
#define PCI_EXT_CAP_ID_NPEM 0x29 /* Native PCIe Enclosure Management */
--
2.47.0