text: /*
   * Copyright (c) 2008, 2013 Citrix Systems, Inc.
   * Copyright (c) 2012 Spectra Logic Corporation
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include <sys/param.h>
  #include <sys/bus.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/proc.h>
  #include <sys/smp.h>
  #include <sys/systm.h>
  
  #include <vm/vm.h>
  #include <vm/pmap.h>
  
  #include <dev/pci/pcivar.h>
  
  #include <machine/cpufunc.h>
  #include <machine/cpu.h>
  #include <machine/smp.h>
  
  #include <x86/apicreg.h>
  
  #include <xen/xen-os.h>
  #include <xen/features.h>
  #include <xen/gnttab.h>
  #include <xen/hypervisor.h>
  #include <xen/hvm.h>
  #include <xen/xen_intr.h>
  
  #include <xen/interface/hvm/params.h>
  #include <xen/interface/vcpu.h>
  
  /*--------------------------- Forward Declarations ---------------------------*/
  static void xen_hvm_cpu_init(void);
  
  /*-------------------------------- Local Types -------------------------------*/
  enum xen_hvm_init_type {
  	XEN_HVM_INIT_COLD,
  	XEN_HVM_INIT_CANCELLED_SUSPEND,
  	XEN_HVM_INIT_RESUME
  };
  
  /*-------------------------------- Global Data -------------------------------*/
  enum xen_domain_type xen_domain_type = XEN_NATIVE;
  
  #ifdef SMP
  struct cpu_ops xen_hvm_cpu_ops = {
  	.cpu_init	= xen_hvm_cpu_init,
  	.cpu_resume	= xen_hvm_cpu_init
  };
  #endif
  
  static MALLOC_DEFINE(M_XENHVM, "xen_hvm", "Xen HVM PV Support");
  
  /**
   * If non-zero, the hypervisor has been configured to use a direct
   * IDT event callback for interrupt injection.
   */
  int xen_vector_callback_enabled;
  
  /*------------------------------- Per-CPU Data -------------------------------*/
  DPCPU_DEFINE(struct vcpu_info, vcpu_local_info);
  DPCPU_DEFINE(struct vcpu_info *, vcpu_info);
  
  /*------------------ Hypervisor Access Shared Memory Regions -----------------*/
  shared_info_t *HYPERVISOR_shared_info;
  start_info_t *HYPERVISOR_start_info;
  
  
  /*------------------------------ Sysctl tunables -----------------------------*/
  int xen_disable_pv_disks = 0;
  int xen_disable_pv_nics = 0;
  TUNABLE_INT("hw.xen.disable_pv_disks", &xen_disable_pv_disks);
  TUNABLE_INT("hw.xen.disable_pv_nics", &xen_disable_pv_nics);
  
  /*---------------------- XEN Hypervisor Probe and Setup ----------------------*/
  static uint32_t
  xen_hvm_cpuid_base(void)
  {
  	uint32_t base, regs[4];
  
  	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
  		do_cpuid(base, regs);
  		if (!memcmp("XenVMMXenVMM", &regs[1], 12)
  		    && (regs[0] - base) >= 2)
  			return (base);
  	}
  	return (0);
  }
  
  /*
   * Allocate and fill in the hypcall page.
   */
  static int
  xen_hvm_init_hypercall_stubs(enum xen_hvm_init_type init_type)
  {
  	uint32_t base, regs[4];
  	int i;
  
  	if (xen_pv_domain()) {
  		/* hypercall page is already set in the PV case */
  		return (0);
  	}
  
  	base = xen_hvm_cpuid_base();
  	if (base == 0)
  		return (ENXIO);
  
  	if (init_type == XEN_HVM_INIT_COLD) {
  		int major, minor;
  
  		do_cpuid(base + 1, regs);
  
  		major = regs[0] >> 16;
  		minor = regs[0] & 0xffff;
  		printf("XEN: Hypervisor version %d.%d detected.\n", major,
  			minor);
  
  		if (((major < 4) || (major == 4 && minor <= 5)) &&
  		    msix_disable_migration == -1) {
  			/*
  			 * Xen hypervisors prior to 4.6.0 do not properly
  			 * handle updates to enabled MSI-X table entries,
  			 * so disable MSI-X interrupt migration in that
  			 * case.
  			 */
  			if (bootverbose)
  				printf(
  "Disabling MSI-X interrupt migration due to Xen hypervisor bug.\n"
  "Set machdep.msix_disable_migration=0 to forcefully enable it.\n");
  			msix_disable_migration = 1;
  		}
  	}
  
  	/*
  	 * Find the hypercall pages.
  	 */
  	do_cpuid(base + 2, regs);
  
  	for (i = 0; i < regs[0]; i++)
  		wrmsr(regs[1], vtophys(&hypercall_page + i * PAGE_SIZE) + i);
  
  	return (0);
  }
  
  static void
  xen_hvm_init_shared_info_page(void)
  {
  	struct xen_add_to_physmap xatp;
  
  	if (xen_pv_domain()) {
  		/*
  		 * Already setup in the PV case, shared_info is passed inside
  		 * of the start_info struct at start of day.
  		 */
  		return;
  	}
  
  	if (HYPERVISOR_shared_info == NULL) {
  		HYPERVISOR_shared_info = malloc(PAGE_SIZE, M_XENHVM, M_NOWAIT);
  		if (HYPERVISOR_shared_info == NULL)
  			panic("Unable to allocate Xen shared info page");
  	}
  
  	xatp.domid = DOMID_SELF;
  	xatp.idx = 0;
  	xatp.space = XENMAPSPACE_shared_info;
  	xatp.gpfn = vtophys(HYPERVISOR_shared_info) >> PAGE_SHIFT;
  	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
  		panic("HYPERVISOR_memory_op failed");
  }
  
  /*
   * Tell the hypervisor how to contact us for event channel callbacks.
   */
  void
  xen_hvm_set_callback(device_t dev)
  {
  	struct xen_hvm_param xhp;
  	int irq;
  
  	if (xen_vector_callback_enabled)
  		return;
  
  	xhp.domid = DOMID_SELF;
  	xhp.index = HVM_PARAM_CALLBACK_IRQ;
  	if (xen_feature(XENFEAT_hvm_callback_vector) != 0) {
  		int error;
  
  		xhp.value = HVM_CALLBACK_VECTOR(IDT_EVTCHN);
  		error = HYPERVISOR_hvm_op(HVMOP_set_param, &xhp);
  		if (error == 0) {
  			xen_vector_callback_enabled = 1;
  			return;
  		}
  		printf("Xen HVM callback vector registration failed (%d). "
  		    "Falling back to emulated device interrupt\n", error);
  	}
  	xen_vector_callback_enabled = 0;
  	if (dev == NULL) {
  		/*
  		 * Called from early boot or resume.
  		 * xenpci will invoke us again later.
  		 */
  		return;
  	}
  
  	irq = pci_get_irq(dev);
  	if (irq < 16) {
  		xhp.value = HVM_CALLBACK_GSI(irq);
  	} else {
  		u_int slot;
  		u_int pin;
  
  		slot = pci_get_slot(dev);
  		pin = pci_get_intpin(dev) - 1;
  		xhp.value = HVM_CALLBACK_PCI_INTX(slot, pin);
  	}
  
  	if (HYPERVISOR_hvm_op(HVMOP_set_param, &xhp) != 0)
  		panic("Can't set evtchn callback");
  }
  
  #define	XEN_MAGIC_IOPORT 0x10
  enum {
  	XMI_MAGIC			 = 0x49d2,
  	XMI_UNPLUG_IDE_DISKS		 = 0x01,
  	XMI_UNPLUG_NICS			 = 0x02,
  	XMI_UNPLUG_IDE_EXCEPT_PRI_MASTER = 0x04
  };
  
  static void
  xen_hvm_disable_emulated_devices(void)
  {
  	u_short disable_devs = 0;
  
  	if (xen_pv_domain()) {
  		/*
  		 * No emulated devices in the PV case, so no need to unplug
  		 * anything.
  		 */
  		if (xen_disable_pv_disks != 0 || xen_disable_pv_nics != 0)
  			printf("PV devices cannot be disabled in PV guests\n");
  		return;
  	}
  
  	if (inw(XEN_MAGIC_IOPORT) != XMI_MAGIC)
  		return;
  
  	if (xen_disable_pv_disks == 0) {
  		if (bootverbose)
  			printf("XEN: disabling emulated disks\n");
  		disable_devs |= XMI_UNPLUG_IDE_DISKS;
  	}
  	if (xen_disable_pv_nics == 0) {
  		if (bootverbose)
  			printf("XEN: disabling emulated nics\n");
  		disable_devs |= XMI_UNPLUG_NICS;
  	}
  
  	if (disable_devs != 0)
  		outw(XEN_MAGIC_IOPORT, disable_devs);
  }
  
  static void
  xen_hvm_init(enum xen_hvm_init_type init_type)
  {
  	int error;
  	int i;
  
  	if (init_type == XEN_HVM_INIT_CANCELLED_SUSPEND)
  		return;
  
  	error = xen_hvm_init_hypercall_stubs(init_type);
  
  	switch (init_type) {
  	case XEN_HVM_INIT_COLD:
  		if (error != 0)
  			return;
  
  		/*
  		 * If xen_domain_type is not set at this point
  		 * it means we are inside a (PV)HVM guest, because
  		 * for PVH the guest type is set much earlier
  		 * (see hammer_time_xen).
  		 */
  		if (!xen_domain()) {
  			xen_domain_type = XEN_HVM_DOMAIN;
  			vm_guest = VM_GUEST_XEN;
  		}
  
  		setup_xen_features();
  #ifdef SMP
  		cpu_ops = xen_hvm_cpu_ops;
  #endif
  		break;
  	case XEN_HVM_INIT_RESUME:
  		if (error != 0)
  			panic("Unable to init Xen hypercall stubs on resume");
  
  		/* Clear stale vcpu_info. */
  		CPU_FOREACH(i)
  			DPCPU_ID_SET(i, vcpu_info, NULL);
  		break;
  	default:
  		panic("Unsupported HVM initialization type");
  	}
  
  	xen_vector_callback_enabled = 0;
  	xen_hvm_set_callback(NULL);
  
  	/*
  	 * On (PV)HVM domains we need to request the hypervisor to
  	 * fill the shared info page, for PVH guest the shared_info page
  	 * is passed inside the start_info struct and is already set, so this
  	 * functions are no-ops.
  	 */
  	xen_hvm_init_shared_info_page();
  	xen_hvm_disable_emulated_devices();
  } 
  
  void
  xen_hvm_suspend(void)
  {
  }
  
  void
  xen_hvm_resume(bool suspend_cancelled)
  {
  
  	xen_hvm_init(suspend_cancelled ?
  	    XEN_HVM_INIT_CANCELLED_SUSPEND : XEN_HVM_INIT_RESUME);
  
  	/* Register vcpu_info area for CPU#0. */
  	xen_hvm_cpu_init();
  }
   
  static void
  xen_hvm_sysinit(void *arg __unused)
  {
  	xen_hvm_init(XEN_HVM_INIT_COLD);
  }
  
  static void
  xen_set_vcpu_id(void)
  {
  	struct pcpu *pc;
  	int i;
  
  	if (!xen_hvm_domain())
  		return;
  
  	/* Set vcpu_id to acpi_id */
  	CPU_FOREACH(i) {
  		pc = pcpu_find(i);
  		pc->pc_vcpu_id = pc->pc_acpi_id;
  		if (bootverbose)
  			printf("XEN: CPU %u has VCPU ID %u\n",
  			       i, pc->pc_vcpu_id);
  	}
  }
  
  static void
  xen_hvm_cpu_init(void)
  {
  	struct vcpu_register_vcpu_info info;
  	struct vcpu_info *vcpu_info;
  	int cpu, rc;
  
  	if (!xen_domain())
  		return;
  
  	if (DPCPU_GET(vcpu_info) != NULL) {
  		/*
  		 * vcpu_info is already set.  We're resuming
  		 * from a failed migration and our pre-suspend
  		 * configuration is still valid.
  		 */
  		return;
  	}
  
  	vcpu_info = DPCPU_PTR(vcpu_local_info);
  	cpu = PCPU_GET(vcpu_id);
  	info.mfn = vtophys(vcpu_info) >> PAGE_SHIFT;
  	info.offset = vtophys(vcpu_info) - trunc_page(vtophys(vcpu_info));
  
  	rc = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
  	if (rc != 0)
  		DPCPU_SET(vcpu_info, &HYPERVISOR_shared_info->vcpu_info[cpu]);
  	else
  		DPCPU_SET(vcpu_info, vcpu_info);
  }
  
  SYSINIT(xen_hvm_init, SI_SUB_HYPERVISOR, SI_ORDER_FIRST, xen_hvm_sysinit, NULL);
  SYSINIT(xen_hvm_cpu_init, SI_SUB_INTR, SI_ORDER_FIRST, xen_hvm_cpu_init, NULL);
  SYSINIT(xen_set_vcpu_id, SI_SUB_CPU, SI_ORDER_ANY, xen_set_vcpu_id, NULL);
  