Commit c6e298e1f12e0f4ca02b6da5e42919ae055f6830
hw/pci: reserve IO and mem for pci-2-pci bridges with no devices attached
introduced support for hot-plugging devices behind pci-2-pci bridges.
Extend hotplug support also for pci express downstream ports.
Signed-off-by: Marcel Apfelbaum <marcel.a(a)redhat.com>
---
v2 -> v3:
Addressed Michael S. Tsirkin comments:
- Refactored pci_bus_hotplug_support function.
- Removed PCI_EXP_FLAGS_TYPE_SHIFT macro.
v1 -> v2:
Wrong prefix on first patch.
src/fw/pciinit.c | 34 ++++++++++++++++++++++++++++++++--
1 file changed, 32 insertions(+), 2 deletions(-)
diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 0ad548f..fd5dfb9 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -636,6 +636,36 @@ pci_region_create_entry(struct pci_bus *bus, struct pci_device *dev,
return entry;
}
+static int pci_bus_hotplug_support(struct pci_bus *bus)
+{
+ u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP);
+ u8 shpc_cap;
+
+ if (pcie_cap) {
+ u16 pcie_flags = pci_config_readw(bus->bus_dev->bdf,
+ pcie_cap + PCI_EXP_FLAGS);
+ u8 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
+ (__builtin_ffs(PCI_EXP_FLAGS_TYPE) - 1));
+ u8 downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
+ (port_type == PCI_EXP_TYPE_ROOT_PORT);
+ /*
+ * PCI Express SPEC, 7.8.2:
+ * Slot Implemented – When Set, this bit indicates that the Link
+ * HwInit associated with this Port is connected to a slot (as
+ * compared to being connected to a system-integrated device or
+ * being disabled).
+ * This bit is valid for Downstream Ports. This bit is undefined
+ * for Upstream Ports.
+ */
+ u16 slot_implemented = pcie_flags & PCI_EXP_FLAGS_SLOT;
+
+ return downstream_port && slot_implemented;
+ }
+
+ shpc_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_SHPC);
+ return !!shpc_cap;
+}
+
static int pci_bios_check_devices(struct pci_bus *busses)
{
dprintf(1, "PCI: check devices\n");
@@ -678,7 +708,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
continue;
struct pci_bus *parent = &busses[pci_bdf_to_bus(s->bus_dev->bdf)];
int type;
- u8 shpc_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_SHPC);
+ int hotplug_support = pci_bus_hotplug_support(s);
for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
u64 align = (type == PCI_REGION_TYPE_IO) ?
PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
@@ -687,7 +717,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
if (pci_region_align(&s->r[type]) > align)
align = pci_region_align(&s->r[type]);
u64 sum = pci_region_sum(&s->r[type]);
- if (!sum && shpc_cap)
+ if (!sum && hotplug_support)
sum = align; /* reserve min size for hot-plug */
u64 size = ALIGN(sum, align);
int is64 = pci_bios_bridge_region_is64(&s->r[type],
--
1.8.3.1