minix/kernel/arch/i386/arch_do_vmctl.c
Tomas Hruby f51eea4b32 Changed pagefault delivery to VM
this patch changes the way pagefaults are delivered to VM. It adopts
the same model as the out-of-quantum messages sent by kernel to a
scheduler.

- everytime a userspace pagefault occurs, kernel creates a message
  which is sent to VM on behalf of the faulting process

- the process is blocked on delivery to VM in the standard IPC code
  instead of waiting in a spacial in-kernel queue (stack) and is not
  runnable until VM tell kernel that the pagefault is resolved and is
  free to clear the RTS_PAGEFAULT flag.

- VM does not need call kernel and poll the pagefault information
  which saves many (1/2?) calls and kernel calls that return "no more
  data"

- VM notification by kernel does not need to use signals

- each entry in proc table is by 12 bytes smaller (~3k save)
2010-04-26 23:21:26 +00:00

72 lines
1.6 KiB
C

/* The kernel call implemented in this file:
* m_type: SYS_VMCTL
*
* The parameters for this kernel call are:
* SVMCTL_WHO which process
* SVMCTL_PARAM set this setting (VMCTL_*)
* SVMCTL_VALUE to this value
*/
#include "kernel/system.h"
#include <minix/type.h>
#include "proto.h"
extern u8_t *vm_pagedirs;
/*===========================================================================*
* arch_do_vmctl *
*===========================================================================*/
PUBLIC int arch_do_vmctl(m_ptr, p)
register message *m_ptr; /* pointer to request message */
struct proc *p;
{
switch(m_ptr->SVMCTL_PARAM) {
case VMCTL_I386_GETCR3:
/* Get process CR3. */
m_ptr->SVMCTL_VALUE = p->p_seg.p_cr3;
return OK;
case VMCTL_I386_SETCR3:
/* Set process CR3. */
if(m_ptr->SVMCTL_VALUE) {
p->p_seg.p_cr3 = m_ptr->SVMCTL_VALUE;
p->p_misc_flags |= MF_FULLVM;
} else {
p->p_seg.p_cr3 = 0;
p->p_misc_flags &= ~MF_FULLVM;
}
RTS_UNSET(p, RTS_VMINHIBIT);
return OK;
case VMCTL_INCSP:
/* Increase process SP. */
p->p_reg.sp += m_ptr->SVMCTL_VALUE;
return OK;
case VMCTL_I386_KERNELLIMIT:
{
int r;
/* VM wants kernel to increase its segment. */
r = prot_set_kern_seg_limit(m_ptr->SVMCTL_VALUE);
return r;
}
case VMCTL_I386_PAGEDIRS:
{
vm_pagedirs = (u8_t *) m_ptr->SVMCTL_VALUE;
return OK;
}
case VMCTL_I386_FREEPDE:
{
i386_freepde(m_ptr->SVMCTL_VALUE);
return OK;
}
case VMCTL_FLUSHTLB:
{
reload_cr3();
return OK;
}
}
printf("arch_do_vmctl: strange param %d\n", m_ptr->SVMCTL_PARAM);
return EINVAL;
}