Commit 6c3fdade authored Mar 09, 2022 by Konrad Sztyber Committed by Jim Harris Mar 10, 2022

vmd: reset root port config before enumeration



The root ports might have been configured by some other driver (e.g.
Linux kernel) prior to loading the SPDK one, so we need to clear it.  We
need to before the scanning process, as it's depth-first, so when
scanning the initial root ports, the latter ones might still be using
stale configuration.  This can lead to two bridges having the same
secondary/subordinate bus configuration, meaning that their config space
would map to the same memory area, which, of course, isn't correct.

This has manifested in issue #2413, where two root ports were configured
to use the same secondary bus.  This caused an endpoint device to be
enumerated twice on two different root ports, with the first instance
being broken once the second port was configured by the SPDK driver.

Fixes #2413

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I5ce0931a84c1d23ccadb93fe39e8155ff1281474
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/11863


Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Reviewed-by: Tom Nabarro <tom.nabarro@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

parent 038f5b2e

lib/vmd/vmd.c

+29 −0

Original line number	Diff line number	Diff line
		@@ -1106,6 +1106,33 @@ vmd_cache_scan_info(struct vmd_pci_device *dev)
		}
		}

		static void
		vmd_reset_root_ports(struct vmd_pci_bus *bus)
		{
		volatile struct pci_header *header;
		uint32_t devfn;

		/*
		* The root ports might have been configured by some other driver (e.g. Linux kernel) prior
		* to loading the SPDK one, so we need to clear it. We need to before the scanning process,
		* as it's depth-first, so when scanning the initial root ports, the latter ones might still
		* be using stale configuration. This can lead to two bridges having the same
		* secondary/subordinate bus configuration, which, of course, isn't correct.
		* (Note: this fixed issue #2413.)
		*/
		for (devfn = 0; devfn < 32; ++devfn) {
		if (!vmd_bus_device_present(bus, devfn)) {
		continue;
		}

		header = (volatile void *)(bus->vmd->cfg_vaddr + CONFIG_OFFSET_ADDR(bus->bus_number,
		devfn, 0, 0));
		if (vmd_device_is_root_port(header) && !vmd_device_is_enumerated(header)) {
		vmd_reset_base_limit_registers(header);
		}
		}
		}

		static uint8_t
		vmd_scan_pcibus(struct vmd_pci_bus *bus)
		{
		@@ -1113,6 +1140,8 @@ vmd_scan_pcibus(struct vmd_pci_bus *bus)
		struct vmd_pci_device *dev;
		uint8_t dev_cnt;

		vmd_reset_root_ports(bus);

		g_end_device_count = 0;
		TAILQ_INSERT_TAIL(&bus->vmd->bus_list, bus, tailq);
		bus->vmd->next_bus_number = bus->bus_number + 1;