vmm_mem.c

/*-
 * Copyright (c) 2011 NetApp, Inc.
 * Copyright (c) 2015 xhyve developers
 * 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 NETAPP, INC ``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 NETAPP, INC 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.
 *
 * $FreeBSD$
 */

#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <Hypervisor/hv.h>
#include <Hypervisor/hv_vmx.h>
#include <xhyve/support/misc.h>
#include <xhyve/vmm/vmm_mem.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/sysctl.h>

/* According to the mono project
   https://github.com/mono/mono/commit/a502768b3a24f4251de6a48ba78a27c898968e63
   using MAP_JIT causes problems with older macOS versions so we should use it
   on Mojave or later. */

static int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_JIT;

#define OSRELEASE "kern.osrelease"
#define OSRELEASE_MOJAVE 18

static long
vmm_get_kern_osrelease()
{
	char *s;
	size_t len;
	long v;
	if (sysctlbyname(OSRELEASE, NULL, &len, NULL, 0)) {
		xhyve_abort("vmm_get_kern_osrelease failed to query sysctl kern.osrelease\n");
	}
	s = malloc(len);
	if (!s) {
		xhyve_abort("vmm_get_kern_osrelease failed to allocate memory for kern.osrelease\n");
	}
	if (sysctlbyname(OSRELEASE, s, &len, NULL, 0)){
		xhyve_abort("vmm_get_kern_osrelease failed to query sysctl kern.osrelease\n");
	}
	v = strtol(s, NULL, 10);
	if ((v == 0) && (errno != 0)) {
		xhyve_abort("vmm_get_kern_osrelease failed to parse sysctl kern.osrelease value\n");
	}
	return v;
}

int
vmm_mem_init(void)
{
	if (vmm_get_kern_osrelease() < OSRELEASE_MOJAVE) {
		fprintf(stderr, "Detected macOS older than Mojave, cannot use MAP_JIT\n");
		mmap_flags &= ~MAP_JIT;
	}
	return (0);
}


void *
vmm_mem_alloc(uint64_t gpa, size_t size)
{
	void *object;

	object = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, mmap_flags, -1, 0);
	if (object == MAP_FAILED) {
		xhyve_abort("vmm_mem_alloc failed in mmap\n");
	}

	if (hv_vm_map(object, gpa, size,
		HV_MEMORY_READ | HV_MEMORY_WRITE | HV_MEMORY_EXEC))
	{
		xhyve_abort("hv_vm_map failed\n");
	}

	return object;
}

void
vmm_mem_free(uint64_t gpa, size_t size, void *object)
{
	hv_vm_unmap(gpa, size);
	free(object);
}

void
vmm_mem_protect(uint64_t gpa, size_t size) {
	hv_vm_protect(gpa, size, 0);
}

void
vmm_mem_unprotect(uint64_t gpa, size_t size) {
	hv_vm_protect(gpa, size, (HV_MEMORY_READ | HV_MEMORY_WRITE | HV_MEMORY_EXEC));
}