[RFC v1 3/4] qemu: patch guest DSDT for GPU memory

[ankita]

From: Ankit Agrawal <ankita@nvidia.com>

To add the memory in the guest as NUMA nodes, it needs the PXM node index
and the total count of nodes associated with the memory. The range of
proximity domains are communicated to the VM as part of the guest ACPI
using the nvidia,gpu-mem-pxm-start and nvidia,gpu-mem-pxm-count DSD
properties. These value respectively represent the staring proximity
domain id and the count. Kernel modules can then fetch this information
and determine the numa node ID using pxm_to_node().

Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
---
 hw/pci-host/gpex-acpi.c | 71 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/hw/pci-host/gpex-acpi.c b/hw/pci-host/gpex-acpi.c
index 7c7316bc96..36873889c1 100644
--- a/hw/pci-host/gpex-acpi.c
+++ b/hw/pci-host/gpex-acpi.c
@@ -49,6 +49,74 @@ static void acpi_dsdt_add_pci_route_table(Aml *dev, uint32_t 
irq)
     }
 }
 
+static void acpi_dsdt_add_gpu(Aml *dev, int32_t devfn,
+                             uint64_t gpu_mem_pxm_start,
+                             uint64_t gpu_mem_pxm_count)
+{
+    Aml *dev_gpu = aml_device("GPU%X", PCI_SLOT(devfn));
+    Aml *pkg = aml_package(2);
+    Aml *pkg1 = aml_package(2);
+    Aml *pkg2 = aml_package(2);
+    Aml *dev_pkg = aml_package(2);
+    Aml *UUID;
+
+    aml_append(dev_gpu, aml_name_decl("_ADR", aml_int(PCI_SLOT(devfn) << 16)));
+
+    aml_append(pkg1, aml_string("nvidia,gpu-mem-pxm-start"));
+    aml_append(pkg1, aml_int(gpu_mem_pxm_start));
+
+    aml_append(pkg2, aml_string("nvidia,gpu-mem-pxm-count"));
+    aml_append(pkg2, aml_int(gpu_mem_pxm_count));
+
+    aml_append(pkg, pkg1);
+    aml_append(pkg, pkg2);
+
+    UUID = aml_touuid("DAFFD814-6EBA-4D8C-8A91-BC9BBF4AA301");
+    aml_append(dev_pkg, UUID);
+    aml_append(dev_pkg, pkg);
+
+    aml_append(dev_gpu, aml_name_decl("_DSD", dev_pkg));
+    aml_append(dev, dev_gpu);
+}
+
+static void find_hbm_device(PCIBus *bus, PCIDevice *pdev,
+                            void *opaque)
+{
+    Aml *dev = (Aml *)opaque;
+    uint32_t vendor_id = pci_default_read_config(pdev, PCI_VENDOR_ID, 2);
+
+    if (bus == NULL) {
+        return;
+    }
+
+    if (vendor_id == PCI_VENDOR_ID_NVIDIA &&
+        pdev->has_coherent_memory) {
+        Object *po = OBJECT(pdev);
+
+        if (po == NULL) {
+            return;
+        }
+
+        uint64_t pxm_start
+           = object_property_get_uint(po, "gpu_mem_pxm_start", NULL);
+        uint64_t pxm_count
+           = object_property_get_uint(po, "gpu_mem_pxm_count", NULL);
+
+        acpi_dsdt_add_gpu(dev, pdev->devfn, pxm_start, pxm_count);
+    }
+}
+
+static void acpi_dsdt_find_and_add_gpu(PCIBus *bus, Aml *dev)
+{
+    if (bus == NULL) {
+        return;
+    }
+
+    pci_for_each_device_reverse(bus, pci_bus_num(bus),
+                                find_hbm_device, dev);
+
+}
+
 static void acpi_dsdt_add_pci_osc(Aml *dev)
 {
     Aml *method, *UUID, *ifctx, *ifctx1, *elsectx, *buf;
@@ -207,7 +275,10 @@ void acpi_dsdt_add_gpex(Aml *scope, struct GPEXConfig *cfg)
 
     acpi_dsdt_add_pci_route_table(dev, cfg->irq);
 
+    acpi_dsdt_find_and_add_gpu(cfg->bus, dev);
+
     method = aml_method("_CBA", 0, AML_NOTSERIALIZED);
+
     aml_append(method, aml_return(aml_int(cfg->ecam.base)));
     aml_append(dev, method);
 
-- 
2.17.1