[PATCH 0/3] Support getting p2pdma_distance

[PATCH 0/3] Support getting p2pdma_distance

[Julia Zhang]

To implement dGPU prime feature, virtgpu needs to import/export buffer
between virtio iGPU and passthrough dGPU. Before that, virtgpu has to
checkout p2pdma_distance. But calling function pci_p2pdma_distance in guest
VM will only get virtual p2pdma_distance instead of real physical
p2pdma_distance.

This series is to support handling the new virtgpu command from the guest
VM to get the physical p2pdma_distance of two PCI devices of guest VM.

Julia Zhang (3):
  virtio-gpu: set hostaddr for virtio iGPU
  pci: introduce a function to get PCIDevice
  virtio-gpu: add a new command to calculate p2pdma_distance

 hw/display/virtio-gpu-virgl.c               | 47 +++++++++++++++++++++
 hw/display/virtio-gpu.c                     |  6 +++
 hw/i386/xen/xen-hvm.c                       |  6 +++
 hw/pci/pci.c                                | 22 ++++++++++
 hw/xen/xen_pt.c                             | 10 ++---
 hw/xen/xen_pt.h                             |  1 -
 include/hw/pci/pci.h                        |  2 +
 include/hw/pci/pci_device.h                 |  1 +
 include/hw/virtio/virtio-gpu-bswap.h        | 12 ++++++
 include/hw/virtio/virtio-gpu.h              |  2 +
 include/hw/xen/xen.h                        |  3 ++
 include/standard-headers/linux/virtio_gpu.h | 19 +++++++++
 12 files changed, 125 insertions(+), 6 deletions(-)

-- 
2.34.1

[PATCH 1/3] virtio-gpu: set hostaddr for virtio iGPU

[Julia Zhang]

Get physical pci notation from hvm file and set hostaddr for virtio
iGPU. 

Signed-off-by: Julia Zhang <julia.zhang@amd.com>
---
 hw/display/virtio-gpu.c        |  6 ++++++
 hw/xen/xen_pt.c                | 10 +++++-----
 hw/xen/xen_pt.h                |  1 -
 include/hw/pci/pci_device.h    |  1 +
 include/hw/virtio/virtio-gpu.h |  2 ++
 5 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index c0570ef856..d68b64ac22 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -26,6 +26,7 @@
 #include "hw/virtio/virtio-gpu-bswap.h"
 #include "hw/virtio/virtio-gpu-pixman.h"
 #include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/virtio-pci.h"
 #include "hw/qdev-properties.h"
 #include "qemu/log.h"
 #include "qemu/memfd.h"
@@ -1458,6 +1459,8 @@ void virtio_gpu_device_realize(DeviceState *qdev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
     VirtIOGPU *g = VIRTIO_GPU(qdev);
+    BusState *qbus = BUS(qdev_get_parent_bus(qdev));
+    VirtIOPCIProxy *proxy = VIRTIO_PCI(qbus->parent);
 
     if (virtio_gpu_blob_enabled(g->parent_obj.conf)) {
         if (!virtio_gpu_rutabaga_enabled(g->parent_obj.conf) &&
@@ -1508,6 +1511,8 @@ void virtio_gpu_device_realize(DeviceState *qdev, Error **errp)
     QTAILQ_INIT(&g->reslist);
     QTAILQ_INIT(&g->cmdq);
     QTAILQ_INIT(&g->fenceq);
+
+    proxy->pci_dev.hostaddr = g->parent_obj.conf.hostaddr;
 }
 
 static void virtio_gpu_device_unrealize(DeviceState *qdev)
@@ -1669,6 +1674,7 @@ static Property virtio_gpu_properties[] = {
                     VIRTIO_GPU_FLAG_BLOB_ENABLED, false),
     DEFINE_PROP_SIZE("hostmem", VirtIOGPU, parent_obj.conf.hostmem, 0),
     DEFINE_PROP_UINT8("x-scanout-vmstate-version", VirtIOGPU, scanout_vmstate_version, 2),
+    DEFINE_PROP_PCI_HOST_DEVADDR("hostaddr", VirtIOGPU, parent_obj.conf.hostaddr),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index c0042b3515..8e5ff09b66 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -828,9 +828,9 @@ static void xen_pt_realize(PCIDevice *d, Error **errp)
 
     /* register real device */
     XEN_PT_LOG(d, "Assigning real physical device %02x:%02x.%d"
-               " to devfn 0x%x\n",
+               " to devfn 0x%x, %02x:%02x.%d\n",
                s->hostaddr.bus, s->hostaddr.slot, s->hostaddr.function,
-               s->dev.devfn);
+               s->dev.devfn, pci_bus_num(pci_get_bus(&s->dev)), PCI_SLOT(s->dev.devfn), PCI_FUNC(s->dev.devfn));
 
     s->is_virtfn = s->real_device.is_virtfn;
     if (s->is_virtfn) {
@@ -991,7 +991,7 @@ static void xen_pt_unregister_device(PCIDevice *d)
 }
 
 static Property xen_pci_passthrough_properties[] = {
-    DEFINE_PROP_PCI_HOST_DEVADDR("hostaddr", XenPCIPassthroughState, hostaddr),
+    DEFINE_PROP_PCI_HOST_DEVADDR("hostaddr", XenPCIPassthroughState, dev.hostaddr),
     DEFINE_PROP_BOOL("permissive", XenPCIPassthroughState, permissive, false),
     DEFINE_PROP_END_OF_LIST(),
 };
@@ -1022,8 +1022,8 @@ static void xen_igd_clear_slot(DeviceState *qdev, Error **errp)
     PCIBus *pci_bus = pci_get_bus(pci_dev);
 
     xen_host_pci_device_get(&s->real_device,
-                            s->hostaddr.domain, s->hostaddr.bus,
-                            s->hostaddr.slot, s->hostaddr.function,
+                            s->dev.hostaddr.domain, s->dev.hostaddr.bus,
+                            s->dev.hostaddr.slot, s->dev.hostaddr.function,
                             errp);
     if (*errp) {
         error_append_hint(errp, "Failed to \"open\" the real pci device");
diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
index 095a0f0365..f61a134ff5 100644
--- a/hw/xen/xen_pt.h
+++ b/hw/xen/xen_pt.h
@@ -233,7 +233,6 @@ typedef struct XenPTMSIX {
 struct XenPCIPassthroughState {
     PCIDevice dev;
 
-    PCIHostDeviceAddress hostaddr;
     bool is_virtfn;
     bool permissive;
     bool permissive_warned;
diff --git a/include/hw/pci/pci_device.h b/include/hw/pci/pci_device.h
index 8eaf0d58bb..b7acf3822d 100644
--- a/include/hw/pci/pci_device.h
+++ b/include/hw/pci/pci_device.h
@@ -56,6 +56,7 @@ typedef struct PCIReqIDCache PCIReqIDCache;
 
 struct PCIDevice {
     DeviceState qdev;
+    PCIHostDeviceAddress hostaddr;
     bool partially_hotplugged;
     bool has_power;
 
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index 553799b8cc..e385794a06 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -24,6 +24,7 @@
 #include "standard-headers/linux/virtio_gpu.h"
 #include "standard-headers/linux/virtio_ids.h"
 #include "qom/object.h"
+#include "hw/pci/pci.h"
 
 #define TYPE_VIRTIO_GPU_BASE "virtio-gpu-base"
 OBJECT_DECLARE_TYPE(VirtIOGPUBase, VirtIOGPUBaseClass,
@@ -125,6 +126,7 @@ struct virtio_gpu_base_conf {
     uint32_t xres;
     uint32_t yres;
     uint64_t hostmem;
+    PCIHostDeviceAddress hostaddr;
 };
 
 struct virtio_gpu_ctrl_command {
-- 
2.34.1

[PATCH 2/3] pci: introduce a function to get PCIDevice

[Julia Zhang]

Introduce a helper function to get PCIDevice from qdev pci notation.

Signed-off-by: Julia Zhang <julia.zhang@amd.com>
---
 hw/pci/pci.c         | 22 ++++++++++++++++++++++
 include/hw/pci/pci.h |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 1416ae202c..95806ead4f 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2617,6 +2617,28 @@ static int pci_qdev_find_recursive(PCIBus *bus,
     return -EINVAL;
 }
 
+int pci_qdev_get_device(uint32_t virt_bus, uint32_t virt_slot, uint32_t virt_func,
+			PCIDevice **pci_dev)
+{
+    PCIHostState *host_bridge;
+    PCIDevice *d;
+    int devfn;
+    int rc = -ENODEV;
+
+    QLIST_FOREACH(host_bridge, &pci_host_bridges, next) {
+        for(devfn = 0; devfn < ARRAY_SIZE(host_bridge->bus->devices); devfn++) {
+	    d = host_bridge->bus->devices[devfn];
+	    if (d && d->devfn == PCI_DEVFN(virt_slot, virt_func) &&
+		pci_bus_num(pci_get_bus(d)) == virt_bus) {
+		*pci_dev = d;
+		rc = 0;
+		break;
+	    }
+	}
+    }
+    return rc;
+}
+
 int pci_qdev_find_device(const char *id, PCIDevice **pdev)
 {
     PCIHostState *host_bridge;
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 463d9984b3..1b493ab95e 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -366,6 +366,8 @@ const char *pci_root_bus_path(PCIDevice *dev);
 bool pci_bus_bypass_iommu(PCIBus *bus);
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn);
 int pci_qdev_find_device(const char *id, PCIDevice **pdev);
+int pci_qdev_get_device(uint32_t virt_bus, uint32_t virt_slot,
+			uint32_t virt_func, PCIDevice **pci_dev);
 void pci_bus_get_w64_range(PCIBus *bus, Range *range);
 
 void pci_device_deassert_intx(PCIDevice *dev);
-- 
2.34.1

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

[Julia Zhang]

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@amd.com>
---
 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

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

[Michael S. Tsirkin]

On Sat, Dec 07, 2024 at 06:55:40PM +0800, Julia Zhang wrote:
> 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

This is not how we change this header.
you need a spec patch, an UAPI change to be accepted into linux.

-- 
MST