[SeaBIOS] [PATCH 2/6] paravirt/qemu: virtio-mmio device discovery

[Gerd Hoffmann]

Use bootorder fw_cfg file to find bootable virtio-mmio devices.
Also add a new virtio-mmio.c source file, providing a function
to register virtio-mmio devices.

Signed-off-by: Gerd Hoffmann 
---
 Makefile             |  2 +-
 src/hw/virtio-mmio.h |  6 ++++++
 src/fw/paravirt.c    | 24 ++++++++++++++++++++++++
 src/hw/virtio-mmio.c | 30 ++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 src/hw/virtio-mmio.h
 create mode 100644 src/hw/virtio-mmio.c

diff --git a/Makefile b/Makefile
index 5f7d5370198a..985ef591a13b 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,7 @@ SRC32FLAT=$(SRCBOTH) post.c e820map.c malloc.c romfile.c x86.c optionroms.c \
     fw/coreboot.c fw/lzmadecode.c fw/multiboot.c fw/csm.c fw/biostables.c \
     fw/paravirt.c fw/shadow.c fw/pciinit.c fw/smm.c fw/smp.c fw/mtrr.c fw/xen.c \
     fw/acpi.c fw/mptable.c fw/pirtable.c fw/smbios.c fw/romfile_loader.c \
-    hw/virtio-ring.c hw/virtio-pci.c hw/virtio-blk.c hw/virtio-scsi.c \
+    hw/virtio-ring.c hw/virtio-pci.c hw/virtio-mmio.c hw/virtio-blk.c hw/virtio-scsi.c \
     hw/tpm_drivers.c hw/nvme.c
 SRC32SEG=string.c output.c pcibios.c apm.c stacks.c hw/pci.c hw/serialio.c
 DIRS=src src/hw src/fw vgasrc
diff --git a/src/hw/virtio-mmio.h b/src/hw/virtio-mmio.h
new file mode 100644
index 000000000000..751984241f49
--- /dev/null
+++ b/src/hw/virtio-mmio.h
@@ -0,0 +1,6 @@
+#ifndef _VIRTIO_MMIO_H
+#define _VIRTIO_MMIO_H
+
+void virtio_mmio_register(u64 mmio);
+
+#endif /* _VIRTIO_MMIO_H */
diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
index 119280c574fd..aaaf8b8dad31 100644
--- a/src/fw/paravirt.c
+++ b/src/fw/paravirt.c
@@ -15,6 +15,7 @@
 #include "hw/pcidevice.h" // pci_probe_devices
 #include "hw/pci_regs.h" // PCI_DEVICE_ID
 #include "hw/serialio.h" // PORT_SERIAL1
+#include "hw/virtio-mmio.h" // virtio_mmio_register
 #include "hw/rtc.h" // CMOS_*
 #include "malloc.h" // malloc_tmp
 #include "output.h" // dprintf
@@ -192,6 +193,27 @@ static void msr_feature_control_setup(void)
         wrmsr_smp(MSR_IA32_FEATURE_CONTROL, feature_control_bits);
 }

+static void qemu_probe_virtio_mmio(void)
+{
+    char *data, *next;
+    int size;
+    u64 mmio;
+
+    data = romfile_loadfile("bootorder", &size);
+    while (data) {
+        next = strchr(data, '\n');
+        if (next) {
+            *next = '\0';
+            next++;
+        }
+        if (memcmp("/virtio-mmio@", data, 13) == 0) {
+            mmio = strtol(data+13, 16);
+            virtio_mmio_register(mmio);
+        }
+        data = next;
+    }
+}
+
 void
 qemu_platform_setup(void)
 {
@@ -217,6 +239,8 @@ qemu_platform_setup(void)
     msr_feature_control_setup();
     smp_setup();

+    qemu_probe_virtio_mmio();
+
     // Create bios tables
     if (MaxCountCPUs <= 255) {
         pirtable_setup();
diff --git a/src/hw/virtio-mmio.c b/src/hw/virtio-mmio.c
new file mode 100644
index 000000000000..0f320921df30
--- /dev/null
+++ b/src/hw/virtio-mmio.c
@@ -0,0 +1,30 @@
+#include "config.h" // CONFIG_DEBUG_LEVEL
+#include "malloc.h" // free
+#include "output.h" // dprintf
+#include "virtio-pci.h"
+#include "virtio-ring.h"
+
+/* qemu microvm supports 8 virtio-mmio devices */
+static u64 devs[8];
+
+void virtio_mmio_register(u64 mmio)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(devs); i++) {
+        if (devs[i] == mmio) {
+            /*
+             * This can happen in case we have multiple scsi devices
+             * attached to a single virtio-scsi controller
+             */
+            dprintf(3, "virtio-mmio: duplicate device at 0x%llx, ignoring\n", mmio);
+            return;
+        }
+        if (devs[i] == 0) {
+            dprintf(1, "virtio-mmio: device at 0x%llx\n", mmio);
+            devs[i] = mmio;
+            return;
+        }
+    }
+    dprintf(1, "virtio-mmio: device list full\n");
+}