If a pci-2-pci bridge supports hot-plug functionality but there are no devices
connected to it, reserve IO/mem in order to be able to attach devices
later. Do not waste space, use minimum allowed.
Signed-off-by: Marcel Apfelbaum <marce...@redhat.com>
---
- Thanks Gerd Hoffmann for the review.
v1 -> v2:
- Addressed Michael S. Tsirkin's comments:
- Limit capabilities query to 256 iterations, to make sure we
don't get into an infinite loop with a broken device.
src/fw/pciinit.c | 3 +++
src/hw/pci.c | 19 +++++++++++++++++++
src/hw/pci.h | 1 +
3 files changed, 23 insertions(+)
diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 64f1d41..9b5d7ad 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -677,12 +677,15 @@ 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);
for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
u64 align = (type == PCI_REGION_TYPE_IO) ?
PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
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)
+ sum = align; /* reserve min size for hot-plug */
u64 size = ALIGN(sum, align);
int is64 = pci_bios_bridge_region_is64(&s->r[type],
s->bus_dev, type);
diff --git a/src/hw/pci.c b/src/hw/pci.c
index caf9265..055353d 100644
--- a/src/hw/pci.c
+++ b/src/hw/pci.c
@@ -225,6 +225,25 @@ pci_find_init_device(const struct pci_device_id *ids, void
*arg)
return NULL;
}
+u8 pci_find_capability(struct pci_device *pci, u8 cap_id)
+{
+ int i;
+ u8 cap;
+ u16 status = pci_config_readw(pci->bdf, PCI_STATUS);
+
+ if (!(status & PCI_STATUS_CAP_LIST))
+ return 0;
+
+ for (i = 0, cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST);
+ (i <= 0xff) && cap;
+ i++, cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT))
+ if (pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_ID) == cap_id)
+ return cap;
+
+ return 0;
+}
+
+
void
pci_reboot(void)
{
diff --git a/src/hw/pci.h b/src/hw/pci.h
index 167a027..e828225 100644
--- a/src/hw/pci.h
+++ b/src/hw/pci.h
@@ -116,6 +116,7 @@ int pci_init_device(const struct pci_device_id *ids
, struct pci_device *pci, void *arg);
struct pci_device *pci_find_init_device(const struct pci_device_id *ids
, void *arg);
+u8 pci_find_capability(struct pci_device *pci, u8 cap_id);
void pci_reboot(void);
#endif
--
1.8.3.1
