From: Nirmal Patel <nirmal.patel@linux.intel.com>
To: Nirmal Patel <nirmal.patel@linux.intel.com>,
<linux-pci@vger.kernel.org>,
jonathan.derrick@linux.dev
Subject: [PATCH v5] PCI: vmd: Clean up domain before enumeration
Date: Tue, 16 Nov 2021 15:11:36 -0700 [thread overview]
Message-ID: <20211116221136.85134-1-nirmal.patel@linux.intel.com> (raw)
During VT-d pass-through, the VMD driver occasionally fails to
enumerate underlying NVMe devices when repetitive reboots are
performed in the guest OS. The issue can be resolved by resetting
VMD root ports for proper enumeration and triggering secondary bus
reset which will also propagate reset through downstream bridges.
Signed-off-by: Nirmal Patel <nirmal.patel@linux.intel.com>
Reviewed-by: Jon Derrick <jonathan.derrick@linux.dev>
---
---
v4->v5: Fixing small nitpick fix.
v3->v4: Using pci_reset_bus function for secondary bus reset instead of
manually triggering secondary bus reset, addressing review
comments of v3.
v2->v3: Combining two functions into one, Remove redundant definations
and Formatting fixes
drivers/pci/controller/vmd.c | 37 ++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index a5987e52700e..a905fce6232f 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -498,6 +498,40 @@ static inline void vmd_acpi_begin(void) { }
static inline void vmd_acpi_end(void) { }
#endif /* CONFIG_ACPI */
+static void vmd_domain_reset(struct vmd_dev *vmd)
+{
+ u16 bus, max_buses = resource_size(&vmd->resources[0]);
+ u8 dev, functions, fn, hdr_type;
+ char __iomem *base;
+
+ for (bus = 0; bus < max_buses; bus++) {
+ for (dev = 0; dev < 32; dev++) {
+ base = vmd->cfgbar + PCIE_ECAM_OFFSET(bus,
+ PCI_DEVFN(dev, 0), 0);
+
+ hdr_type = readb(base + PCI_HEADER_TYPE) &
+ PCI_HEADER_TYPE_MASK;
+
+ functions = (hdr_type & 0x80) ? 8 : 1;
+ for (fn = 0; fn < functions; fn++) {
+ base = vmd->cfgbar + PCIE_ECAM_OFFSET(bus,
+ PCI_DEVFN(dev, fn), 0);
+
+ hdr_type = readb(base + PCI_HEADER_TYPE) &
+ PCI_HEADER_TYPE_MASK;
+
+ if (hdr_type != PCI_HEADER_TYPE_BRIDGE ||
+ (readw(base + PCI_CLASS_DEVICE) !=
+ PCI_CLASS_BRIDGE_PCI))
+ continue;
+
+ memset_io(base + PCI_IO_BASE, 0,
+ PCI_ROM_ADDRESS1 - PCI_IO_BASE);
+ }
+ }
+ }
+}
+
static void vmd_attach_resources(struct vmd_dev *vmd)
{
vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1];
@@ -801,6 +835,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
vmd_acpi_begin();
pci_scan_child_bus(vmd->bus);
+ vmd_domain_reset(vmd);
+ list_for_each_entry(child, &vmd->bus->children, node)
+ pci_reset_bus(child->self);
pci_assign_unassigned_bus_resources(vmd->bus);
/*
--
2.27.0
next reply other threads:[~2021-11-16 22:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-16 22:11 Nirmal Patel [this message]
2021-11-19 20:48 ` [PATCH v5] PCI: vmd: Clean up domain before enumeration Patel, Nirmal
2021-11-19 20:55 ` Bjorn Helgaas
2021-12-01 12:01 ` Lorenzo Pieralisi
2021-12-02 16:38 ` Patel, Nirmal
2021-12-02 17:32 ` Keith Busch
2021-12-03 18:18 ` Bjorn Helgaas
2021-12-04 2:34 ` Patel, Nirmal
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