[PATCH 3/3] virtio-gpu: add a new command to get p2pdma_distance

[Julia Zhang <julia.zhang@xxxxxxx>]

To implement passthrough dGPU prime in guest, virtio-gpu need to check
p2pdma_distance of two GPUs. This adds a new command for guest to pass
virtual pci notations of two pci devices to host and send xen privcmd to
calculate physical p2pdma_distance.

Signed-off-by: Julia Zhang <julia.zhang@xxxxxxx>
---
 hw/display/virtio-gpu-virgl.c               | 47 +++++++++++++++++++++
 hw/i386/xen/xen-hvm.c                       |  6 +++
 include/hw/virtio/virtio-gpu-bswap.h        | 12 ++++++
 include/hw/xen/xen.h                        |  3 ++
 include/standard-headers/linux/virtio_gpu.h | 19 +++++++++
 5 files changed, 87 insertions(+)

diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index 07faeb1834..eb9b193ade 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -16,6 +16,12 @@
 #include "qemu/iov.h"
 #include "trace.h"
 #include "hw/virtio/virtio.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/virtio/virtio-pci.h"
+#include "hw/virtio/virtio-bus.h"
+#include "hw/xen/xen.h"
+
 #include "hw/virtio/virtio-gpu.h"
 #include "hw/virtio/virtio-gpu-bswap.h"
 #include "hw/virtio/virtio-gpu-pixman.h"
@@ -188,6 +194,44 @@ virtio_gpu_virgl_unmap_resource_blob(VirtIOGPU *g,
 
     return 0;
 }
+
+static void virgl_cmd_p2pdma_distance(VirtIOGPU *g,
+                                     struct virtio_gpu_ctrl_command *cmd)
+{
+    struct virtio_gpu_device_p2pdma_distance cmd_p;
+    struct virtio_gpu_resp_distance resp;
+    PCIDevice *client = NULL, *provider = NULL;
+    int ret;
+
+    VIRTIO_GPU_FILL_CMD(cmd_p);
+    virtio_gpu_p2pdma_distance_bswap(&cmd_p);
+
+    ret = pci_qdev_get_device(cmd_p.provider_bus, cmd_p.provider_slot, 
cmd_p.provider_func, &provider);
+
+    if (ret) {
+           qemu_log_mask(LOG_GUEST_ERROR, "%s: virgl get physical device 
error: %s\n",
+                         __func__, strerror(-ret));
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+        return;
+    }
+
+    ret = pci_qdev_get_device(cmd_p.client_bus, cmd_p.client_slot, 
cmd_p.client_func, &client);
+    if (ret) {
+           qemu_log_mask(LOG_GUEST_ERROR, "%s: virgl get physical device 
error: %s\n",
+                         __func__, strerror(-ret));
+        cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER;
+        return;
+    }
+
+    int distance = xen_p2pdma_distance(provider->hostaddr.bus, 
provider->hostaddr.slot,
+                                      
provider->hostaddr.function,client->hostaddr.bus,
+                                      client->hostaddr.slot, 
client->hostaddr.function);
+
+    memset(&resp, 0, sizeof(resp));
+    resp.hdr.type = VIRTIO_GPU_RESP_OK_P2PDMA_DISTANCE;
+    resp.distance = distance;
+    virtio_gpu_ctrl_response(g, cmd, &resp.hdr, sizeof(resp));
+}
 #endif
 
 static void virgl_cmd_create_resource_2d(VirtIOGPU *g,
@@ -913,6 +957,9 @@ void virtio_gpu_virgl_process_cmd(VirtIOGPU *g,
     case VIRTIO_GPU_CMD_SUBMIT_3D:
         virgl_cmd_submit_3d(g, cmd);
         break;
+    case VIRTIO_GPU_CMD_P2PDMA_DISTANCE:
+       virgl_cmd_p2pdma_distance(g, cmd);
+       break;
     case VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D:
         virgl_cmd_transfer_to_host_2d(g, cmd);
         break;
diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index d3df488c48..c8dd27dad7 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -604,6 +604,12 @@ static bool xen_check_stubdomain(struct xs_handle *xsh)
     return is_stubdom;
 }
 
+int xen_p2pdma_distance(uint32_t bus, uint32_t slot, uint32_t func,
+                       uint32_t c_bus, uint32_t c_slot, uint32_t c_func)
+{
+       return xc_physdev_p2pdma_distance(xen_xc, bus, slot, func, c_bus, 
c_slot, c_func);
+}
+
 void xen_hvm_init_pc(PCMachineState *pcms, MemoryRegion **ram_memory)
 {
     MachineState *ms = MACHINE(pcms);
diff --git a/include/hw/virtio/virtio-gpu-bswap.h 
b/include/hw/virtio/virtio-gpu-bswap.h
index dd1975e2d4..b5c0c0adcd 100644
--- a/include/hw/virtio/virtio-gpu-bswap.h
+++ b/include/hw/virtio/virtio-gpu-bswap.h
@@ -78,6 +78,18 @@ virtio_gpu_map_blob_bswap(struct 
virtio_gpu_resource_map_blob *mblob)
     le64_to_cpus(&mblob->offset);
 }
 
+static inline void
+virtio_gpu_p2pdma_distance_bswap(struct virtio_gpu_device_p2pdma_distance 
*p2p_dist)
+{
+    virtio_gpu_ctrl_hdr_bswap(&p2p_dist->hdr);
+    le32_to_cpus(&p2p_dist->provider_bus);
+    le32_to_cpus(&p2p_dist->provider_slot);
+    le32_to_cpus(&p2p_dist->provider_func);
+    le32_to_cpus(&p2p_dist->client_bus);
+    le32_to_cpus(&p2p_dist->client_bus);
+    le32_to_cpus(&p2p_dist->client_bus);
+}
+
 static inline void
 virtio_gpu_unmap_blob_bswap(struct virtio_gpu_resource_unmap_blob *ublob)
 {
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index ecb89ecfc1..fe1d628327 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -48,4 +48,7 @@ qemu_irq *xen_interrupt_controller_init(void);
 
 void xen_register_framebuffer(struct MemoryRegion *mr);
 
+int xen_p2pdma_distance(uint32_t bus, uint32_t slot, uint32_t func,
+                       uint32_t c_bus, uint32_t c_slot, uint32_t c_func);
+
 #endif /* QEMU_HW_XEN_H */
diff --git a/include/standard-headers/linux/virtio_gpu.h 
b/include/standard-headers/linux/virtio_gpu.h
index 6459fdb9fb..2e55dcc2fe 100644
--- a/include/standard-headers/linux/virtio_gpu.h
+++ b/include/standard-headers/linux/virtio_gpu.h
@@ -95,6 +95,7 @@ enum virtio_gpu_ctrl_type {
        VIRTIO_GPU_CMD_SUBMIT_3D,
        VIRTIO_GPU_CMD_RESOURCE_MAP_BLOB,
        VIRTIO_GPU_CMD_RESOURCE_UNMAP_BLOB,
+       VIRTIO_GPU_CMD_P2PDMA_DISTANCE,
 
        /* cursor commands */
        VIRTIO_GPU_CMD_UPDATE_CURSOR = 0x0300,
@@ -108,6 +109,7 @@ enum virtio_gpu_ctrl_type {
        VIRTIO_GPU_RESP_OK_EDID,
        VIRTIO_GPU_RESP_OK_RESOURCE_UUID,
        VIRTIO_GPU_RESP_OK_MAP_INFO,
+       VIRTIO_GPU_RESP_OK_P2PDMA_DISTANCE,
 
        /* error responses */
        VIRTIO_GPU_RESP_ERR_UNSPEC = 0x1200,
@@ -429,6 +431,23 @@ struct virtio_gpu_set_scanout_blob {
        uint32_t offsets[4];
 };
 
+/* VIRTIO_GPU_CMD_P2PDMA_DISTANCE */
+struct virtio_gpu_device_p2pdma_distance {
+       struct virtio_gpu_ctrl_hdr hdr;
+       __le32 provider_bus;
+       __le32 provider_slot;
+       __le32 provider_func;
+       __le32 client_bus;
+       __le32 client_slot;
+       __le32 client_func;
+};
+
+/* VIRTIO_GPU_RESP_DISTANCE */
+struct virtio_gpu_resp_distance {
+       struct virtio_gpu_ctrl_hdr hdr;
+       __le32 distance;
+};
+
 /* VIRTIO_GPU_CMD_RESOURCE_MAP_BLOB */
 struct virtio_gpu_resource_map_blob {
        struct virtio_gpu_ctrl_hdr hdr;
-- 
2.34.1