acrn-dm: implement cpu_affinity command line argument

User has a chance to specify VCPU affinity through acrn-dm command line
argument. Examples of the command line:

3 PCPUs: 1/2/3
--cpu_affinity 1-3

5 PCPUs: 2/3/6/7/8
--cpu_affinity 2,3,6-8

8 PCPUs: 2/3/6/7/9/10/11/12
--cpu_affinity 2,3,6-7,9,10-12

The specified pCPUs must be included in the guest VM's statically
defined vm_config[].cpu_affinity_bitmap.

Tracked-On: #4616
Signed-off-by: Zide Chen <zide.chen@intel.com>

devicemodel/core/main.c

@@ -164,6 +164,7 @@ usage(int code)
 #endif
 		"       --vsbl: vsbl file path\n"
 		"       --ovmf: ovmf file path\n"
+		"       --pcpu_list: list of pCPUs assigned to this VM\n"
 		"       --part_info: guest partition info file path\n"
 		"       --enable_trusty: enable trusty for guest\n"
 		"       --debugexit: enable debug exit function\n"
@@ -718,6 +719,7 @@ sig_handler_term(int signo)
 enum {
 	CMD_OPT_VSBL = 1000,
 	CMD_OPT_OVMF,
+	CMD_OPT_PCPU_LIST,
 	CMD_OPT_PART_INFO,
 	CMD_OPT_TRUSTY_ENABLE,
 	CMD_OPT_VIRTIO_POLL_ENABLE,
@@ -757,6 +759,7 @@ static struct option long_options[] = {
 #endif
 	{"vsbl",		required_argument,	0, CMD_OPT_VSBL},
 	{"ovmf",		required_argument,	0, CMD_OPT_OVMF},
+	{"pcpu_list",		required_argument,	0, CMD_OPT_PCPU_LIST},
 	{"part_info",		required_argument,	0, CMD_OPT_PART_INFO},
 	{"enable_trusty",	no_argument,		0,
 					CMD_OPT_TRUSTY_ENABLE},
@@ -874,6 +877,10 @@ main(int argc, char *argv[])
 				errx(EX_USAGE, "invalid ovmf param %s", optarg);
 			skip_pci_mem64bar_workaround = true;
 			break;
+		case CMD_OPT_PCPU_LIST:
+			if (acrn_parse_pcpu_list(optarg) != 0)
+				errx(EX_USAGE, "invalid pcpu param %s", optarg);
+			break;
 		case CMD_OPT_PART_INFO:
 			if (acrn_parse_guest_part_info(optarg) != 0) {
 				errx(EX_USAGE,

devicemodel/core/vmmapi.c

@@ -85,6 +85,82 @@ check_api(int fd)
 }
 
 static int devfd = -1;
+static uint64_t cpu_affinity_bitmap = 0UL;
+
+static void add_one_pcpu(int pcpu_id)
+{
+	if (cpu_affinity_bitmap & (1UL << pcpu_id)) {
+		pr_err("%s: pcpu_id %d has been allocated to this VM.\n", __func__, pcpu_id);
+		return;
+	}
+
+	cpu_affinity_bitmap |= (1UL << pcpu_id);
+}
+
+/*
+ * example options:
+ *   --pcpu_list 1,2,3
+ *   --pcpu_list 1-3
+ *   --pcpu_list 1,3,4-6
+ *   --pcpu_list 1,3,4-6,9
+ */
+int acrn_parse_pcpu_list(char *opt)
+{
+	char *str, *cp;
+	int pcpu_id;
+	int pcpu_start, pcpu_end;
+
+	cp = strdup(opt);
+	if (!cp) {
+		pr_err("%s: strdup returns NULL\n", __func__);
+		return -1;
+	}
+
+	while (cp) {
+		str = strpbrk(cp, ",-");
+
+		/* no more entries delimited by ',' or '-' */
+		if (!str) {
+			if (!dm_strtoi(cp, NULL, 10, &pcpu_id)) {
+				add_one_pcpu(pcpu_id);
+				break;
+			}
+		}
+
+		if (*str == ',') {
+			/* after this, 'cp' points to the character after ',' */
+			str = strsep(&cp, ",");
+
+			/* parse the entry before ',' */
+			if (dm_strtoi(str, NULL, 10, &pcpu_id)) {
+				return -1;
+			}
+			add_one_pcpu(pcpu_id);
+		}
+
+		if (*str == '-') {
+			str = strsep(&cp, "-");
+
+			/* parse the entry before and after '-' respectively */
+			if (dm_strtoi(str, NULL, 10, &pcpu_start) || dm_strtoi(cp, NULL, 10, &pcpu_end)) {
+				return -1;
+			}
+
+			if (pcpu_end <= pcpu_start) {
+				return -1;
+			}
+
+			for (; pcpu_start <= pcpu_end; pcpu_start++) {
+				add_one_pcpu(pcpu_start);
+			}
+
+			/* skip the ',' after pcpu_end */
+			str = strsep(&cp, ",");
+		}
+	}
+
+	return 0;
+}
 
 struct vmctx *
 vm_create(const char *name, uint64_t req_buf, int *vcpu_num)
@@ -150,6 +226,9 @@ vm_create(const char *name, uint64_t req_buf, int *vcpu_num)
 		create_vm.vm_flag &= (~GUEST_FLAG_IO_COMPLETION_POLLING);
 	}
 
+	/* command line arguments specified CPU affinity could overwrite HV's static configuration */
+	create_vm.cpu_affinity = cpu_affinity_bitmap;
+
 	if (is_rtvm) {
 		create_vm.vm_flag |= GUEST_FLAG_RT;
 		create_vm.vm_flag |= GUEST_FLAG_IO_COMPLETION_POLLING;

devicemodel/include/vmmapi.h

@@ -134,6 +134,7 @@ int	vm_set_ptdev_intx_info(struct vmctx *ctx, uint16_t virt_bdf,
 int	vm_reset_ptdev_intx_info(struct vmctx *ctx, uint16_t virt_bdf,
 	uint16_t phys_bdf, int virt_pin, bool pic_pin);
 
+int	acrn_parse_pcpu_list(char *arg);
 int	vm_create_vcpu(struct vmctx *ctx, uint16_t vcpu_id);
 int	vm_set_vcpu_regs(struct vmctx *ctx, struct acrn_set_vcpu_regs *cpu_regs);