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HV: reimplement PCI device discovery

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Major changes:

1. Correct handling of device multi-function capability

We only check function zero for this feature. If it has it, we continue
looking at all remaining functions, ignoring those with invalid vendors.
The PCI spec says we are not to probe beyond function zero if it does
not exist or indicates it is not a multi-function device.

2a. Walk *ALL* buses in the PCI space, however,
Before walking the PCI hierarchy, post-processed ACPI DMAR info is parsed
and a map is created between all device-scopes across all DRHDs and the
corresponding IOMMU index.

This map is used at the time of walking the PCI hierarchy. If a BDF that
ACRN is currently working on, is found in the above-mentioned map, the
BDF device is mapped to the corresponding DRHD in the map.
If the BDF were a bridge type, realized with "Header Type" in config space,
the BDF device along with all its downstream devices are mapped to the
corresponding DRHD in the map.

To avoid walking previously visited buses, we maintain a bitmap that
stores which bus is walked when we handle Bridge type devices.

Once ACPI information is included into ACRN about the PCI-Express Root
Complexes / PCI Host Bridges, we can avoid the final loop which probes
all remainder buses, and instead jump to the next Host Bridge bus.

From prior patches, init_pdev returns the pdev structure it created to
the caller. This allows us to complete initialization by updating its
drhd_idx to the correct DRHD.

Tracked-On: #4134
Signed-off-by: Alexander Merritt <alex.merritt@intel.com>
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
This commit is contained in:
Sainath Grandhi
2019-11-01 00:22:46 -07:00
committed by wenlingz
parent 94a456ae24
commit 422330d4ab
2 changed files with 210 additions and 43 deletions
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6
hypervisor/include/hw/pci.h
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@@ -237,6 +237,12 @@ uint32_t pci_pdev_read_cfg(union pci_bdf bdf, uint32_t offset, uint32_t bytes);
void pci_pdev_write_cfg(union pci_bdf bdf, uint32_t offset, uint32_t bytes, uint32_t val);
void enable_disable_pci_intx(union pci_bdf bdf, bool enable);
/*
* @brief Walks the PCI heirarchy and initializes array of pci_pdev structs
* Uses DRHD info from ACPI DMAR tables to cover the endpoints and
* bridges along with their hierarchy captured in the device scope entries
* Walks through rest of the devices starting at bus 0 and thru PCI_BUSMAX
*/
void init_pci_pdev_list(void);
/* @brief: Find the DRHD index corresponding to a PCI device