From 6aab5622296b990024ee67dd7efa7d143e7558d0 Mon Sep 17 00:00:00 2001 From: Nirmal Patel Date: Tue, 16 Nov 2021 15:11:36 -0700 Subject: [PATCH] PCI: vmd: Clean up domain before enumeration 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. Link: https://lore.kernel.org/r/20211116221136.85134-1-nirmal.patel@linux.intel.com Signed-off-by: Nirmal Patel Signed-off-by: Lorenzo Pieralisi Reviewed-by: Jon Derrick --- 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 a45e8e59d3d48..02ffd40108e2f 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -501,6 +501,40 @@ 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]; @@ -805,6 +839,9 @@ 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); /*