[SeaBIOS] [RFC PATCH v4 17/30] pci: Use paravirt interface for pcimem_start and pcimem64_start

[Vasilis Liaskovitis]

Initialize the 32-bit and 64-bit pci starting offsets from values passed in by
the qemu paravirt interface QEMU_CFG_PCI_WINDOW. Qemu calculates the starting
offsets based on initial memory and hotplug-able dimms.
It's possible to avoid the new paravirt interface, and calculate pci ranges from
srat entries. But the code changes are ugly, see:
http://lists.gnu.org/archive/html/qemu-devel/2012-09/msg03548.html
---
 src/paravirt.c |    6 ++++++
 src/paravirt.h |    2 ++
 src/pciinit.c  |    9 +++++++++
 3 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/src/paravirt.c b/src/paravirt.c
index 4b5c441..f7517b9 100644
--- a/src/paravirt.c
+++ b/src/paravirt.c
@@ -347,3 +347,9 @@ void qemu_cfg_romfile_setup(void)
         dprintf(3, "Found fw_cfg file: %s (size=%d)\n", file->name, file->size);
     }
 }
+
+void qemu_cfg_get_pci_offsets(u64 *pcimem_start, u64 *pcimem64_start)
+{
+    qemu_cfg_read_entry(pcimem_start, QEMU_CFG_PCI_WINDOW, sizeof(u64));
+    qemu_cfg_read((u8*)(pcimem64_start), sizeof(u64));
+}
diff --git a/src/paravirt.h b/src/paravirt.h
index a284c41..b53ff88 100644
--- a/src/paravirt.h
+++ b/src/paravirt.h
@@ -35,6 +35,7 @@ static inline int kvm_para_available(void)
 #define QEMU_CFG_BOOT_MENU              0x0e
 #define QEMU_CFG_MAX_CPUS               0x0f
 #define QEMU_CFG_FILE_DIR               0x19
+#define QEMU_CFG_PCI_WINDOW             0x1a
 #define QEMU_CFG_ARCH_LOCAL             0x8000
 #define QEMU_CFG_ACPI_TABLES            (QEMU_CFG_ARCH_LOCAL + 0)
 #define QEMU_CFG_SMBIOS_ENTRIES         (QEMU_CFG_ARCH_LOCAL + 1)
@@ -65,5 +66,6 @@ struct e820_reservation {
 u32 qemu_cfg_e820_entries(void);
 void* qemu_cfg_e820_load_next(void *addr);
 void qemu_cfg_romfile_setup(void);
+void qemu_cfg_get_pci_offsets(u64 *pcimem_start, u64 *pcimem64_start);
 
 #endif
diff --git a/src/pciinit.c b/src/pciinit.c
index a406bbd..4103d2d 100644
--- a/src/pciinit.c
+++ b/src/pciinit.c
@@ -734,6 +734,7 @@ static void pci_bios_map_devices(struct pci_bus *busses)
 void
 pci_setup(void)
 {
+    u64 pv_pcimem_start, pv_pcimem64_start;
     if (CONFIG_COREBOOT || usingXen()) {
         // PCI setup already done by coreboot or Xen - just do probe.
         pci_probe_devices();
@@ -769,5 +770,13 @@ pci_setup(void)
 
     pci_bios_init_devices();
 
+    /* if qemu gives us other pci window values, it means there are hotplug-able
+     * dimms. Adjust accordingly */
+    qemu_cfg_get_pci_offsets(&pv_pcimem_start, &pv_pcimem64_start);
+    if (pv_pcimem_start > pcimem_start)
+        pcimem_start = pv_pcimem_start;
+    if (pv_pcimem64_start > pcimem64_start)
+        pcimem64_start = pv_pcimem64_start;
+
     free(busses);
 }
-- 
1.7.9