[Qemu-devel] kqemu port to FreeBSD 5.x + qemu patch

[Pierre Beyssac <pb@freebsd.org>]

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Hello,

I have written a kqemu wrapper for FreeBSD 5.x (attached). It seems
to work (I've had no crash at all) but it's alpha quality and it
currently lacks working kqemu_free_page() and kqemu_vfree() hooks
(which were never called by kqemu-mid-i386.o in my tests).

I would be interested in any comments. It's substantially different
from the code posted here by Antony T Curtis.

I have also attached a patch to qemu/osdep.c to replace the mmaped
"swap" file with a MAP_ANON area; using a file is unnecessary under
FreeBSD; perhaps it's been done this way due to Linux peculiarities,
but I don't see why. The patch doesn't help performance noticeably
but it saves some precious disk or ramdisk space.
-- 
A: Yes.					  Pierre Beyssac pb@freebsd.org
>Q: Are you sure?
>>A: Because it reverses the logical flow of conversation.
>>>Q: Why is top posting annoying in email?

[-- Attachment #2: kmod-freebsd.c --]
[-- Type: text/plain, Size: 7367 bytes --]

/* $Id: kmod-freebsd.c,v 1.3 2005/03/23 17:53:24 pb Exp $ */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/ioccom.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <machine/vmparam.h>
#include <machine/stdarg.h>

#define __KERNEL__

#include "kqemu.h"

MALLOC_DECLARE(M_KQEMU);
MALLOC_DEFINE(M_KQEMU, "kqemu", "kqemu buffers");

#define	USER_BASE	0x1000

/* quick and dirty convert a physical address to a virtual address */
static vm_offset_t pa_to_va(vm_paddr_t pa, vm_offset_t beg, vm_offset_t end)
{
    struct vmspace *vm = curproc->p_vmspace;
    vm_offset_t va;
    pmap_t pmap;
    pmap = vm_map_pmap(&vm->vm_map);
    for (va = beg; va != end; va += PAGE_SIZE)
	if (pa == pmap_extract(pmap, va))
	    return va;
    printf("pa_to_va failed: pa=%08x\n", pa);
    return -1;
}

/* lock the page at virtual address 'user_addr' and return its
   physical page index. Return -1 if error */
unsigned long CDECL kqemu_lock_user_page(unsigned long user_addr)
{
    struct vmspace *vm = curproc->p_vmspace;
    vm_offset_t va = user_addr;
    vm_paddr_t pa = 0;
    int ret;
    pmap_t pmap;
    ret = vm_map_wire(&vm->vm_map, va, va+PAGE_SIZE, VM_MAP_WIRE_USER);
    if (ret != KERN_SUCCESS) {
	printf("kqemu_lock_user_page(%08lx) failed, ret=%d\n", user_addr, ret);
	return -1;
    }
    pmap = vm_map_pmap(&vm->vm_map);
    pa = pmap_extract(pmap, va);
    // printf("kqemu_lock_user_page(%08lx) va=%08x pa=%08x\n", user_addr, va, pa);
    return pa >> PAGE_SHIFT;
}

void CDECL kqemu_unlock_user_page(unsigned long page_index)
{
    struct vmspace *vm = curproc->p_vmspace;
    vm_offset_t va;
    int ret;
    // printf("kqemu_unlock_user_page(%08lx)\n", page_index);
    va = pa_to_va(page_index << PAGE_SHIFT, USER_BASE, KERNBASE);
    ret = vm_map_unwire(&vm->vm_map, va, va+PAGE_SIZE, VM_MAP_WIRE_USER);
    if (ret != KERN_SUCCESS) {
	printf("kqemu_unlock_user_page(%08lx) failed, ret=%d\n", page_index, ret);
    }
}

/*
 * Allocate a new page. The page must be mapped in the kernel space.
 * Return the page_index or -1 if error.
 */
unsigned long CDECL kqemu_alloc_zeroed_page(void)
{
    pmap_t pmap;
    vm_offset_t va;
    vm_paddr_t pa;

    va = kmem_alloc(kernel_map, PAGE_SIZE);
    if (va == 0) {
	printf("kqemu_alloc_zeroed_page: NULL\n");
	return -1;
    }
    pmap = vm_map_pmap(kernel_map);
    pa = pmap_extract(pmap, va);
    // printf("kqemu_alloc_zeroed_page: %08x\n", pa);
    return pa >> PAGE_SHIFT;
}

void CDECL kqemu_free_page(unsigned long page_index)
{
    printf("kqemu_free_page(%08lx)\n", page_index);
}

/* return kernel address of the physical page page_index */
void *CDECL kqemu_page_kaddr(unsigned long page_index)
{
    vm_offset_t va;
    va = pa_to_va(page_index << PAGE_SHIFT, KERNBASE, 0);
    if (va != -1) {
	printf("kqemu_page_kaddr(%08lx)=%08x\n", page_index, va);
	return (void *)va;
    }
    printf("kqemu_page_kaddr(%08lx)=NOT FOUND\n", page_index);
    return NULL;
}

/* contraint: each page of the vmalloced area must be in the first 4
   GB of physical memory */
void * CDECL kqemu_vmalloc(unsigned int size)
{
    struct vmspace *vm = curproc->p_vmspace;
    vm_offset_t va = USER_BASE;
    int rv;
    if (size % PAGE_SIZE != 0) {
	printf("kqemu_vmalloc(%d) not a multiple of page size\n", size);
	return NULL;
    }
    rv = vm_map_find(&vm->vm_map, NULL, 0, &va, size, 1,
		     VM_PROT_ALL, VM_PROT_ALL, 0);
    if (rv != KERN_SUCCESS) {
	printf("kqemu_vmalloc(%d) failed rv=%d\n", size, rv);
	return NULL;
    }
    printf("kqemu_vmalloc(%d): %08x\n", size, va);
    return (void *)va;
}

void CDECL kqemu_vfree(void *ptr)
{
    printf("kqemu_vfree(%p)\n", ptr);
}

/* return the physical page index for a given virtual page */
unsigned long CDECL kqemu_vmalloc_to_phys(const void *vaddr)
{
    struct vmspace *vm = curproc->p_vmspace;
    vm_paddr_t pa;
    pmap_t pmap;

    pmap = vm_map_pmap(&vm->vm_map);
    pa = pmap_extract(pmap, (vm_offset_t)vaddr);
    if (pa == 0) {
	printf("kqemu_vmalloc_to_phys(%p)->error\n", vaddr);
	return -1;
    }
    printf("kqemu_vmalloc_to_phys(%p)->%08x\n", vaddr, pa);
    return pa >> PAGE_SHIFT;
}

/* return TRUE if a signal is pending (i.e. the guest must stop
   execution) */
int CDECL kqemu_schedule(void)
{
    // printf("kqemu_schedule\n");
    mtx_lock_spin(&sched_lock);
    mi_switch(SW_VOL, NULL);
    mtx_unlock_spin(&sched_lock);
    return SIGPENDING(curthread);
}

static char log_buf[4096];

void CDECL kqemu_log(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(log_buf, sizeof(log_buf), fmt, ap);
    printf("kqemu: %s", log_buf);
    va_end(ap);
}

struct kqemu_instance { 
    //    struct semaphore sem;  
    struct kqemu_state *state;
};

static d_close_t kqemu_close;
static d_open_t kqemu_open;
static d_ioctl_t kqemu_ioctl;

static struct cdevsw kqemu_cdevsw = {
	.d_version =	D_VERSION,
	.d_flags =	D_NEEDGIANT,
	.d_open =	kqemu_open,
	.d_ioctl =	kqemu_ioctl,
	.d_close =	kqemu_close,
	.d_name =	"kqemu"
};

/* For use with make_dev(9)/destroy_dev(9). */
static struct cdev *kqemu_dev;

/* ARGSUSED */
static int
kqemu_open(struct cdev *dev, int flags, int fmt __unused,
    struct thread *td)
{
    struct kqemu_instance *ks;
    ks = malloc(sizeof(struct kqemu_instance), M_KQEMU, M_WAITOK);
    if (ks == NULL) {
	printf("malloc failed\n");
	return ENOMEM;
    }
    ks->state = NULL;
    dev->si_drv1 = ks;
    return 0;
}

/* ARGSUSED */
static int
kqemu_ioctl(struct cdev *dev, u_long cmd, caddr_t addr, 
    int flags __unused, struct thread *td)
{
    int error = 0;
    int ret;
    struct kqemu_instance *ks = dev->si_drv1;
    struct kqemu_state *s = ks->state;

    switch(cmd) {
    case KQEMU_INIT: {
	struct kqemu_init d1, *d = &d1;
	if (s != NULL) {
	    error = EIO;
	    break;
	}
	d1 = *(struct kqemu_init *)addr;
	printf("ram_base=%p ram_size=%ld\n", d1.ram_base, d1.ram_size);
	s = kqemu_init(d, 16000);
	if (s == NULL) {
	    error = ENOMEM;
	    break;
	}
	ks->state = s;
	break;
    }
    case KQEMU_EXEC: {
	struct kqemu_cpu_state *ctx;
	if (s == NULL) {
	    error = EIO;
	    break;
	}
	ctx = kqemu_get_cpu_state(s);
	*ctx = *(struct kqemu_cpu_state *)addr;
	DROP_GIANT();
	ret = kqemu_exec(s);
	PICKUP_GIANT();
	td->td_retval[0] = ret;
	*(struct kqemu_cpu_state *)addr = *ctx;
	break;
    }
    case KQEMU_GET_VERSION:
	*(int *)addr = KQEMU_VERSION;
	break;
    default:
	error = EINVAL;
    }
    return error;
}

/* ARGSUSED */
static int
kqemu_close(struct cdev *dev __unused, int flags, int fmt __unused,
    struct thread *td)
{
	return 0;
}

/* ARGSUSED */
static int
kqemu_modevent(module_t mod __unused, int type, void *data __unused)
{
    int error = 0;

    switch (type) {
    case MOD_LOAD:
	printf("kqemu version 0x%08x\n", KQEMU_VERSION);
	kqemu_dev = make_dev(&kqemu_cdevsw, 0,
			     UID_ROOT, GID_WHEEL, 0666, "kqemu");
	break;
    case MOD_UNLOAD:
	destroy_dev(kqemu_dev);
	break;
    case MOD_SHUTDOWN:
	break;
    default:
	error = EOPNOTSUPP;
	break;
    }
    return (error);
}

DEV_MODULE(kqemu, kqemu_modevent, NULL);
MODULE_VERSION(kqemu, 1);

[-- Attachment #3: Makefile --]
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# $Id: Makefile,v 1.1.1.1 2005/03/23 12:29:35 pb Exp $
KMOD=	kqemu
SRCS=	kmod-freebsd.c
OBJS=	kqemu-mod-i386.o

.include <bsd.kmod.mk>

[-- Attachment #4: patch-osdep.c --]
[-- Type: text/plain, Size: 820 bytes --]

--- osdep.c.orig	Mon Feb 21 21:10:36 2005
+++ osdep.c	Wed Mar 23 18:10:33 2005
@@ -321,6 +321,7 @@
     char phys_ram_file[1024];
     void *ptr;
 
+#if 0
     if (phys_ram_fd < 0) {
         tmpdir = getenv("QEMU_TMPDIR");
         if (!tmpdir)
@@ -349,12 +350,20 @@
         }
         unlink(phys_ram_file);
     }
+#endif
     size = (size + 4095) & ~4095;
+#if 0
     ftruncate(phys_ram_fd, phys_ram_size + size);
     ptr = mmap(NULL, 
                size, 
                PROT_WRITE | PROT_READ, MAP_SHARED, 
                phys_ram_fd, phys_ram_size);
+#else
+    ptr = mmap(NULL, 
+               size, 
+               PROT_WRITE | PROT_READ, MAP_PRIVATE|MAP_ANON, 
+               -1, 0);
+#endif
     if (ptr == MAP_FAILED) {
         fprintf(stderr, "Could not map physical memory\n");
         exit(1);