[Qemu-devel] [PATCH v5] fw/pci: Add support for mapping Intel IGD via QEMU

[Alex Williamson <alex.williamson@redhat.com>]

QEMU provides two fw_cfg files to support IGD.  The first holds the
OpRegion data which holds the Video BIOS Table (VBT).  This needs to
be copied into reserved memory and the address stored in the ASL
Storage register of the device at 0xFC offset in PCI config space.
The OpRegion is generally 8KB.  This file is named "etc/igd-opregion".

The second file tells us the required size of the stolen memory space
for the device.  This space requires 1MB alignment and is generally
either 1MB to 8MB depending on hardware config, but may be hundreds of
MB for user specified stolen memory.  The base address of the reserved
memory allocated for this is written back to the Base Data of Stolen
Memory register (BDSM) at PCI config offset 0x5C on the device.  This
file is named "etc/igd-bdsm-size".

QEMU documents these fw_cfg entries in docs/igd-assign.txt.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

v6: fw_cfg BDSM entry now holds an 8-byte size integer as suggested
    by Gerd.  Also renamed to etc/igd-bdsm-size.  Filter based on bdf
    to only make use of this for the Intel VGA device at address
    00:02.0, not that QEMU should attach this to anything else.

As always, comments appreciated.  I expect this will be on hold
pending the QEMU support:

http://thread.gmane.org/gmane.comp.emulators.kvm.devel/152123

If there's a better way to sync these projects, please let me know.
Thanks,

Alex

 src/fw/pciinit.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
index 35d9902..08221e6 100644
--- a/src/fw/pciinit.c
+++ b/src/fw/pciinit.c
@@ -287,6 +287,50 @@ static void ich9_smbus_setup(struct pci_device *dev, void *arg)
     ich9_smbus_enable(dev->bdf);
 }
 
+static void intel_igd_setup(struct pci_device *dev, void *arg)
+{
+    struct romfile_s *opregion = romfile_find("etc/igd-opregion");
+    u64 bdsm_size = le64_to_cpu(romfile_loadint("etc/igd-bdsm-size", 0));
+    void *addr;
+    u16 bdf = dev->bdf;
+
+    /* Apply OpRegion to any Intel VGA device, more than one is undefined */
+    if (opregion && opregion->size) {
+        addr = memalign_high(PAGE_SIZE, opregion->size);
+        if (!addr) {
+            warn_noalloc();
+            return;
+        }
+
+        if (opregion->copy(opregion, addr, opregion->size) < 0) {
+            free(addr);
+            return;
+        }
+
+        pci_config_writel(bdf, 0xFC, cpu_to_le32((u32)addr));
+
+        dprintf(1, "Intel IGD OpRegion enabled at 0x%08x, size %dKB, dev "
+                "%02x:%02x.%x\n", (u32)addr, opregion->size >> 10,
+                pci_bdf_to_bus(bdf), pci_bdf_to_dev(bdf), pci_bdf_to_fn(bdf));
+    }
+
+    /* Apply BDSM only to Intel VGA at 00:02.0 */
+    if (bdsm_size && (bdf == pci_to_bdf(0, 2, 0))) {
+        addr = memalign_tmphigh(1024 * 1024, bdsm_size);
+        if (!addr) {
+            warn_noalloc();
+            return;
+        }
+
+        e820_add((u32)addr, bdsm_size, E820_RESERVED);
+
+        pci_config_writel(bdf, 0x5C, cpu_to_le32((u32)addr));
+
+        dprintf(1, "Intel IGD BDSM enabled at 0x%08x, size %lldMB, dev "
+                "00:02.0\n", (u32)addr, bdsm_size >> 20);
+    }
+}
+
 static const struct pci_device_id pci_device_tbl[] = {
     /* PIIX3/PIIX4 PCI to ISA bridge */
     PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371SB_0,
@@ -320,6 +364,10 @@ static const struct pci_device_id pci_device_tbl[] = {
     PCI_DEVICE_CLASS(PCI_VENDOR_ID_APPLE, 0x0017, 0xff00, apple_macio_setup),
     PCI_DEVICE_CLASS(PCI_VENDOR_ID_APPLE, 0x0022, 0xff00, apple_macio_setup),
 
+    /* Intel IGD OpRegion setup */
+    PCI_DEVICE_CLASS(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA,
+                     intel_igd_setup),
+
     PCI_DEVICE_END,
 };