dm: fill region ID to dm-land ivshmem PCI config space

  1) region ID shall be configured by user via config tool.
  2) region ID is programmed to "Subsystem ID" of PCI config space.
  2) "Subsystem Vendor ID" is harded coded as 0x8086

  Parameters to configure dm-land IVSHMEM device example generated
  by config tool as below:
  `add_virtual_device   8 ivshmem hv:/shm_region_0,256,2`

Tracked-On: projectacrn#8566
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>
Reviewed-by: Jian Jun Chen <jian.jun.chen@intel.com>

devicemodel/hw/pci/ivshmem.c

@@ -53,6 +53,7 @@
 #define	IVSHMEM_DEVICE_ID	0x1110
 #define	IVSHMEM_CLASS		0x05
 #define	IVSHMEM_REV		0x01
+#define IVSHMEM_INTEL_SUBVENDOR_ID      0x8086U
 
 
 /* IVSHMEM MMIO Registers */
@@ -249,13 +250,13 @@ pci_ivshmem_read(struct vmctx *ctx, int vcpu, struct pci_vdev *dev,
 static int
 pci_ivshmem_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 {
-	uint32_t size;
-	char *tmp, *name, *orig;
+	uint32_t size, region_id = 0;
+	char *tmp, *name, *size_str, *orig;
 	struct pci_ivshmem_vdev *ivshmem_vdev = NULL;
 	bool is_hv_land;
 	int rc;
 
-	/* ivshmem device usage: "-s N,ivshmem,shm_name,shm_size" */
+	/* ivshmem device usage: "-s N,ivshmem,shm_name,shm_size,region_id" */
 	tmp = orig = strdup(opts);
 	if (!orig) {
 		pr_warn("No memory for strdup\n");
@@ -277,8 +278,9 @@ pci_ivshmem_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 		goto err;
 	}
 
-	if (dm_strtoui(tmp, &tmp, 10, &size) != 0) {
-		pr_warn("the shared memory size is incorrect, %s\n", tmp);
+	size_str = strsep(&tmp, ",");
+	if (dm_strtoui(size_str, &size_str, 10, &size) != 0) {
+		pr_warn("the shared memory size is incorrect, %s\n", size_str);
 		goto err;
 	}
 	size *= 0x100000; /* convert to megabytes */
@@ -289,6 +291,13 @@ pci_ivshmem_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 		goto err;
 	}
 
+	if (tmp) {
+		if (dm_strtoui(tmp, &tmp, 10, &region_id) != 0) {
+			pr_warn("shared memory region ID is incorrect, %s, 0 will used.\n", tmp);
+			region_id = 0;
+		}
+	}
+
 	ivshmem_vdev = calloc(1, sizeof(struct pci_ivshmem_vdev));
 	if (!ivshmem_vdev) {
 		pr_warn("failed to allocate ivshmem device\n");
@@ -304,6 +313,8 @@ pci_ivshmem_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
 	pci_set_cfgdata16(dev, PCIR_DEVICE, IVSHMEM_DEVICE_ID);
 	pci_set_cfgdata16(dev, PCIR_REVID, IVSHMEM_REV);
 	pci_set_cfgdata8(dev, PCIR_CLASS, IVSHMEM_CLASS);
+	pci_set_cfgdata16(dev, PCIR_SUBDEV_0, (uint16_t)region_id);
+	pci_set_cfgdata16(dev, PCIR_SUBVEND_0, IVSHMEM_INTEL_SUBVENDOR_ID);
 
 	pci_emul_alloc_bar(dev, IVSHMEM_MMIO_BAR, PCIBAR_MEM32, IVSHMEM_REG_SIZE);
 	pci_emul_alloc_bar(dev, IVSHMEM_MSIX_BAR, PCIBAR_MEM32, IVSHMEM_MSIX_PBA_SIZE);