Add IOCTL to support haxm max vcpu value query

core/include/config.h

@@ -66,12 +66,13 @@ struct config_t {
     int no_msr_pass_through;
 };
 
-#define HAX_MAX_VCPUS 16
 
 #ifdef HAX_PLATFORM_NETBSD
-// TODO: Handle 64 VMs
+// TODO: Handle 64 VMs and 64 VCPUs
+#define HAX_MAX_VCPUS 16
 #define HAX_MAX_VMS 8
 #else
+#define HAX_MAX_VCPUS 64
 // Matches the number of bits in vm_mid_bits (see vm.c)
 #define HAX_MAX_VMS 64
 #endif

include/darwin/hax_interface_mac.h

@@ -41,6 +41,7 @@
 #define HAX_IOCTL_DESTROY_VM _IOW(0, 0x22, uint32_t)
 #define HAX_IOCTL_CAPABILITY _IOR(0, 0x23, struct hax_capabilityinfo)
 #define HAX_IOCTL_SET_MEMLIMIT _IOWR(0, 0x24, struct hax_set_memlimit)
+#define HAX_IOCTL_CAP_MAX_VCPU _IOR(0, 0x25, uint32_t)
 
 // Only for backward compatibility with old Qemu.
 #define HAX_VM_IOCTL_VCPU_CREATE_ORIG _IOR(0, 0x80, int)

include/linux/hax_interface_linux.h

@@ -42,6 +42,7 @@
 #define HAX_IOCTL_DESTROY_VM _IOW(0, 0x22, uint32_t)
 #define HAX_IOCTL_CAPABILITY _IOR(0, 0x23, struct hax_capabilityinfo)
 #define HAX_IOCTL_SET_MEMLIMIT _IOWR(0, 0x24, struct hax_set_memlimit)
+#define HAX_IOCTL_CAP_MAX_VCPU _IOR(0, 0x25, uint32_t)
 
 // Only for backward compatibility with old Qemu.
 #define HAX_VM_IOCTL_VCPU_CREATE_ORIG _IOR(0, 0x80, int)

include/netbsd/hax_interface_netbsd.h

@@ -45,6 +45,7 @@
 #define HAX_IOCTL_DESTROY_VM _IOW(0, 0x22, uint32_t)
 #define HAX_IOCTL_CAPABILITY _IOR(0, 0x23, struct hax_capabilityinfo)
 #define HAX_IOCTL_SET_MEMLIMIT _IOWR(0, 0x24, struct hax_set_memlimit)
+#define HAX_IOCTL_CAP_MAX_VCPU _IOR(0, 0x25, uint32_t)
 
 // Only for backward compatibility with old Qemu.
 #define HAX_VM_IOCTL_VCPU_CREATE_ORIG _IOR(0, 0x80, int)

platforms/darwin/com_intel_hax_ui.c

@@ -29,6 +29,7 @@
  */
 
 #include "com_intel_hax.h"
+#include "../../core/include/config.h"
 
 #include <libkern/version.h>
 #include <sys/proc.h>
@@ -596,7 +597,10 @@ static int hax_ioctl(dev_t dev, u_long cmd, caddr_t data, int flag,
             *((uint32_t *)data) = vm_id;
             break;
         }
-
+        case HAX_IOCTL_CAP_MAX_VCPU: {
+            *((uint32_t *)data) = HAX_MAX_VCPUS;
+            break;
+        }
         default: {
             handle_unknown_ioctl(dev, cmd, p);
             ret = -ENOSYS;

platforms/linux/components.c

@@ -653,6 +653,7 @@ static long hax_vm_ioctl(struct file *filp, unsigned int cmd,
     default:
         // TODO: Print information about the process that sent the ioctl.
         hax_log(HAX_LOGE, "Unknown VM IOCTL 0x%lx\n", cmd);
+        ret = -ENOSYS;
         break;
     }
     hax_put_vm(cvm);

platforms/linux/hax_entry.c

@@ -39,6 +39,7 @@
 #include "../../include/hax_interface.h"
 #include "../../include/hax_release_ver.h"
 #include "../../core/include/hax_core_interface.h"
+#include "../../core/include/config.h"
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Kryptos Logic");
@@ -106,7 +107,18 @@ static long hax_dev_ioctl(struct file *filp, unsigned int cmd,
             return -EFAULT;
         break;
     }
+    case HAX_IOCTL_CAP_MAX_VCPU: {
+        int max_vcpu = HAX_MAX_VCPUS;
+
+        if (copy_to_user(argp, &max_vcpu, sizeof(max_vcpu)))
+            return -EFAULT;
+
+        break;
+    }
+
     default:
+        hax_log(HAX_LOGE, "Invalid HAX IOCTL 0x%lx\n", cmd);
+        ret = -ENOSYS;
         break;
     }
     return ret;

platforms/netbsd/hax_entry_hax.c

@@ -116,6 +116,10 @@ int hax_ioctl(dev_t self __unused, u_long cmd, void *data, int flag,
         *((uint32_t *)data) = vm_id;
         break;
     }
+    case HAX_IOCTL_CAP_MAX_VCPU: {
+        *((uint32_t *)data) = HAX_MAX_VCPUS;
+        break;
+    }
     default:
         hax_log(HAX_LOGE, "Unknown ioctl %#lx, pid=%d ('%s')\n", cmd,
                 l->l_proc->p_pid, l->l_proc->p_comm);

platforms/windows/hax_entry.c

@@ -35,6 +35,7 @@
 #include <string.h>
 
 #include "hax_win.h"
+#include "../../core/include/config.h"
 
 // vcpu.h
 int vcpu_takeoff(struct vcpu_t *vcpu);
@@ -714,6 +715,15 @@ NTSTATUS HaxDeviceControl(PDEVICE_OBJECT DeviceObject,
             infret = sizeof(uint32_t);
             ret = STATUS_SUCCESS;
             break;
+        case HAX_IOCTL_CAP_MAX_VCPU:
+            if (outBufLength < sizeof(uint32_t)) {
+                ret = STATUS_BUFFER_TOO_SMALL;
+                goto done;
+            }
+            *((uint32_t *)outBuf) = HAX_MAX_VCPUS;
+            infret = sizeof(uint32_t);
+            ret = STATUS_SUCCESS;
+            break;
         default:
             ret = STATUS_INVALID_DEVICE_REQUEST;
             hax_log(HAX_LOGE, "Invalid hax ioctl %x\n",

platforms/windows/hax_entry.h

@@ -120,6 +120,8 @@ extern PDRIVER_OBJECT HaxDriverObject;
         CTL_CODE(HAX_DEVICE_TYPE, 0x910, METHOD_BUFFERED, FILE_ANY_ACCESS)
 #define HAX_IOCTL_SET_MEMLIMIT \
         CTL_CODE(HAX_DEVICE_TYPE, 0x911, METHOD_BUFFERED, FILE_ANY_ACCESS)
+#define HAX_IOCTL_CAP_MAX_VCPU \
+        CTL_CODE(HAX_DEVICE_TYPE, 0x917, METHOD_BUFFERED, FILE_ANY_ACCESS)
 
 #define HAX_VM_IOCTL_VCPU_CREATE \
         CTL_CODE(HAX_DEVICE_TYPE, 0x902, METHOD_BUFFERED, FILE_ANY_ACCESS)