pci: add qemu gpex host bridge support.microvm

Find PCIe root using ACPI DSDT table.
Setup PCI bars.
initialize PCI devices.

Working:
 - finds + drives xhci-pci / virtio-pci devices.

TODO / known issues:
 - ioport setup is broken.
 - bootorder needs fixing.
 - 64bit mmio window not supported.
 - irq routing not supported.
 - pci config access in real mode is broken (not using mmconfig).
   - this breaks pcibios support.
     - which in turn breaks vgabios.
   - fixable via temporary modeswitch to 32bit.
     - which of course adds overhead.

Also:
 - needed in the first place for microvm?

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index fba4e52d..76070e18 100644
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -198,6 +198,67 @@ static void msr_feature_control_setup(void)
 }
 
 void
+gpex_setup(void)
+{
+    u16 pcie_eisaid = 0x0a08;
+    u16 ecam_eisaid = 0x0c02;
+    u16 link_eisaid = 0x0c0f;
+    struct acpi_device *pcie;
+    struct acpi_device *ecam;
+    struct acpi_device *link;
+    u64 min, max, irq;
+
+    if (!hlist_empty(&PCIDevices)) {
+        dprintf(1, "%s: have pci devices, skipping\n", __func__);
+        return;
+    }
+
+    pcie = acpi_dsdt_find_eisaid(NULL, pcie_eisaid);
+    if (!pcie)
+        return;
+
+    for (ecam = acpi_dsdt_find_eisaid(NULL, ecam_eisaid);
+         ecam != NULL;
+         ecam = acpi_dsdt_find_eisaid(ecam, ecam_eisaid)) {
+        if (acpi_dsdt_is_parent(ecam, pcie))
+            break;
+    }
+    if (!ecam)
+        return;
+
+    if (acpi_dsdt_find_mem(ecam, &min, &max) < 0)
+        return;
+    dprintf(1, "%s: mmconfig: %llx -> %llx\n", __func__, min, max);
+    pci_enable_mmconfig(min, "gpex");
+
+    if (acpi_dsdt_find_io(pcie, &min, &max) < 0)
+        dprintf(1, "%s: no io window [ TODO ]\n", __func__);
+    else
+        dprintf(1, "%s: io: %llx -> %llx [ TODO ]\n", __func__, min, max);
+
+    if (acpi_dsdt_find_mem(pcie, &pcimem_start, &pcimem_end) < 0)
+        return;
+    dprintf(1, "%s: mmio32: %llx -> %llx\n", __func__, pcimem_start, pcimem_end);
+
+    dprintf(1, "%s: mmio64: [ TODO ]\n", __func__);
+
+    for (link = acpi_dsdt_find_eisaid(NULL, link_eisaid);
+         link != NULL;
+         link = acpi_dsdt_find_eisaid(link, link_eisaid)) {
+        if (!acpi_dsdt_is_parent(link, pcie))
+            continue;
+        if (acpi_dsdt_find_irq(link, &irq) < 0)
+            continue;
+        dprintf(1, "%s: %s -> uid %lld, irq %lld [ TODO ]\n", __func__,
+                acpi_dsdt_name(link), acpi_dsdt_uid(link), irq);
+    }
+
+    dprintf(1, "=== PCI device probing ===\n");
+    pci_probe_devices();
+    pci_setup_alloc();
+}
+
+void
 qemu_platform_setup(void)
 {
     if (!CONFIG_QEMU)
@@ -240,6 +301,7 @@ qemu_platform_setup(void)
 
         if (RsdpAddr) {
             acpi_dsdt_parse();
+            gpex_setup();
             virtio_mmio_setup_acpi();
             return;
         }