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| author | Francisco Munoz <francisco.munoz.ruiz@linux.intel.com> | 2022-12-05 17:16:37 -0700 |
|---|---|---|
| committer | Lorenzo Pieralisi <lpieralisi@kernel.org> | 2022-12-06 11:45:25 +0100 |
| commit | 0a584655ef89541dae4d48d2c523b1480ae80284 (patch) | |
| tree | 16a9ba2b36951dc16b27d2b3a2d9f4c2b5ba814a | |
| parent | d899aa668498c07ff217b666ae9712990306e682 (diff) | |
| download | linux-stable-0a584655ef89541dae4d48d2c523b1480ae80284.tar.gz linux-stable-0a584655ef89541dae4d48d2c523b1480ae80284.tar.bz2 linux-stable-0a584655ef89541dae4d48d2c523b1480ae80284.zip | |
PCI: vmd: Fix secondary bus reset for Intel bridges
The reset was never applied in the current implementation because Intel
Bridges owned by VMD are parentless. Internally, pci_reset_bus() applies
a reset to the parent of the PCI device supplied as argument, but in this
case it failed because there wasn't a parent.
In more detail, this change allows the VMD driver to enumerate NVMe devices
in pass-through configurations when guest reboots are performed. There was
an attempted to fix this, but later we discovered that the code inside
pci_reset_bus() wasn’t triggering secondary bus resets. Therefore, we
updated the parameters passed to it, and now NVMe SSDs attached to VMD
bridges are properly enumerated in VT-d pass-through scenarios.
Link: https://lore.kernel.org/r/20221206001637.4744-1-francisco.munoz.ruiz@linux.intel.com
Fixes: 6aab5622296b ("PCI: vmd: Clean up domain before enumeration")
Signed-off-by: Francisco Munoz <francisco.munoz.ruiz@linux.intel.com>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Nirmal Patel <nirmal.patel@linux.intel.com>
Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
| -rw-r--r-- | drivers/pci/controller/vmd.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 98e0746e681c..769eedeb8802 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -719,6 +719,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) resource_size_t offset[2] = {0}; resource_size_t membar2_offset = 0x2000; struct pci_bus *child; + struct pci_dev *dev; int ret; /* @@ -859,8 +860,25 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) pci_scan_child_bus(vmd->bus); vmd_domain_reset(vmd); - list_for_each_entry(child, &vmd->bus->children, node) - pci_reset_bus(child->self); + + /* When Intel VMD is enabled, the OS does not discover the Root Ports + * owned by Intel VMD within the MMCFG space. pci_reset_bus() applies + * a reset to the parent of the PCI device supplied as argument. This + * is why we pass a child device, so the reset can be triggered at + * the Intel bridge level and propagated to all the children in the + * hierarchy. + */ + list_for_each_entry(child, &vmd->bus->children, node) { + if (!list_empty(&child->devices)) { + dev = list_first_entry(&child->devices, + struct pci_dev, bus_list); + if (pci_reset_bus(dev)) + pci_warn(dev, "can't reset device: %d\n", ret); + + break; + } + } + pci_assign_unassigned_bus_resources(vmd->bus); /* |