ref: 37e0d4ab29c8483aab727b76effaec009b650153
dir: /sys/src/cmd/vmx/x86.c/
#include <u.h>
#include <libc.h>
#include <thread.h>
#include "dat.h"
#include "fns.h"
#include "x86.h"
typedef struct VMemReq VMemReq;
struct VMemReq {
QLock;
uintptr va, len;
void *buf;
uintptr rc;
int wr;
};
static uintptr
translateflat(uintptr va, uintptr *pa, int *perm)
{
if(sizeof(uintptr) != 4 && va >> 32 != 0) return 0;
*pa = va;
if(va == 0)
return 0xFFFFFFFFUL;
if(perm != 0) *perm = -1;
return -va;
}
static uintptr
translate32(uintptr va, uintptr *pa, int *perm)
{
void *pd, *pt;
u32int pde, pte;
if(sizeof(uintptr) != 4 && va >> 32 != 0) return -1;
pd = gptr(rget("cr3") & ~0xfff, 4096);
if(pd == nil) return 0;
pde = GET32(pd, (va >> 22) * 4);
if(perm != nil) *perm = pde;
if((pde & 1) == 0) return 0;
if((pde & 0x80) != 0 && (rget("cr4real") & Cr4Pse) != 0){
*pa = pde & 0xffc00000 | (uintptr)(pde & 0x3fe000) << 19 | va & 0x3fffff;
return 0x400000 - (va & 0x3fffff);
}
pt = gptr(pde & ~0xfff, 4096);
if(pt == nil) return 0;
pte = GET32(pt, va >> 10 & 0xffc);
if((pte & 1) == 0) return 0;
if(perm != nil) *perm &= pte;
*pa = pte & ~0xfff | va & 0xfff;
return 0x1000 - (va & 0xfff);
}
static uintptr
translatepae(uintptr, uintptr *, int *)
{
vmerror("PAE translation not implemented");
return 0;
}
static uintptr
translate64(uintptr, uintptr *, int *)
{
vmerror("long mode translation not implemented");
return 0;
}
static uintptr (*
translator(void))(uintptr, uintptr *, int *)
{
uintptr cr0, cr4, efer;
cr0 = rget("cr0real");
if((cr0 & Cr0Pg) == 0)
return translateflat;
efer = rget("efer");
if((efer & EferLme) != 0)
return translate64;
cr4 = rget("cr4real");
if((cr4 & Cr4Pae) != 0)
return translatepae;
return translate32;
}
static void
vmemread0(void *aux)
{
VMemReq *req;
uintptr va, pa, n, ok, pok;
void *v;
uintptr (*trans)(uintptr, uintptr *, int *);
uchar *p;
int wr;
req = aux;
va = req->va;
n = req->len;
p = req->buf;
wr = req->wr;
trans = translator();
while(n > 0){
ok = trans(va, &pa, nil);
if(ok == 0) break;
if(ok > n) ok = n;
v = gptr(pa, 1);
if(v == nil) break;
pok = gavail(v);
if(ok > pok) ok = pok;
if(wr)
memmove(v, p, ok);
else
memmove(p, v, ok);
n -= ok;
p += ok;
va += ok;
}
req->rc = req->len - n;
qunlock(req);
}
uintptr
vmemread(void *buf, uintptr len, uintptr va)
{
VMemReq req;
memset(&req, 0, sizeof(VMemReq));
req.wr = 0;
req.buf = buf;
req.len = len;
req.va = va;
qlock(&req);
sendnotif(vmemread0, &req);
qlock(&req);
return req.rc;
}
uintptr
vmemwrite(void *buf, uintptr len, uintptr va)
{
VMemReq req;
memset(&req, 0, sizeof(VMemReq));
req.wr = 1;
req.buf = buf;
req.len = len;
req.va = va;
qlock(&req);
sendnotif(vmemread0, &req);
qlock(&req);
return req.rc;
}
int
x86access(int seg, uintptr addr0, int asz, uvlong *val, int sz, int acc, TLB *tlb)
{
int cpl;
static char *baser[] = {"csbase", "dsbase", "esbase", "fsbase", "gsbase", "ssbase"};
static char *limitr[] = {"cslimit", "dslimit", "eslimit", "fslimit", "gslimit", "sslimit"};
static char *permr[] = {"csperm", "dsperm", "esperm", "fsperm", "gsperm", "ssperm"};
u32int limit, perm;
uintptr addr, base, szmax;
int pperm, wp, i;
uintptr pa[8], pav;
uintptr l;
uchar *ptr;
switch(asz){
case 2: addr0 = (u16int)addr0; break;
case 4: addr0 = (u32int)addr0; break;
case 8: break;
default:
vmerror("invalid asz=%d in x86access", asz);
assert(0);
}
assert(seg < SEGMAX && (uint)acc <= ACCX);
addr = addr0;
if(tlb != nil && tlb->asz == asz && tlb->seg == seg && tlb->acc == acc && addr >= tlb->start && addr + sz >= addr && addr + sz < tlb->end){
ptr = tlb->base + addr;
goto fast;
}
if(sizeof(uintptr) == 8 && asz == 8){
if(seg == SEGFS || seg == SEGGS)
addr += rget(baser[seg]);
if((u16int)((addr >> 48) + 1) > 1){
gpf:
vmdebug("gpf");
postexc("#gp", 0);
return -1;
}
if((vlong)addr >= 0)
szmax = (1ULL<<48) - addr;
else
szmax = -addr;
}else{
limit = rget(limitr[seg]);
perm = rget(permr[seg]);
if((perm & 0xc) == 0x4){
if((u32int)(addr + sz - 1) < addr || addr <= limit)
goto limfault;
szmax = (u32int)-addr;
}else{
if((u64int)addr + sz - 1 >= limit){
limfault:
vmdebug("limit fault");
postexc(seg == SEGSS ? "#ss" : "#gp", 0);
return -1;
}
szmax = limit - addr + 1;
}
if((perm & 0x10080) != 0x80)
goto gpf;
switch(acc){
case ACCR: if((perm & 0xa) == 8) goto gpf; break;
case ACCW: if((perm & 0xa) != 2) goto gpf; break;
case ACCX: if((perm & 8) == 0) goto gpf; break;
}
base = rget(baser[seg]);
addr = (u32int)(addr + base);
}
cpl = rget("cs") & 3;
wp = (rget("cr0real") & 1<<16) != 0;
for(i = 0; i < sz; ){
l = translator()(addr+i, &pav, &pperm);
if(l == 0){
pf:
vmdebug("page fault @ %#p", addr+i);
postexc("#pf", pperm & 1 | (acc == ACCW) << 1 | (cpl == 3) << 2 | (acc == ACCX) << 4);
rset("cr2", addr+i);
return -1;
}
if((cpl == 3 || wp) && acc == ACCW && (pperm & 2) == 0)
goto pf;
if(cpl == 3 && (pperm & 4) == 0)
goto pf;
if(i == 0 && l < szmax) szmax = l;
while(i < sz && l-- > 0)
pa[i++] = pav++;
}
if(szmax >= sz){
ptr = gptr(pa[0], sz);
if(ptr == nil) goto slow;
if(tlb != nil){
l = gavail(ptr);
if(l < szmax) szmax = l;
tlb->asz = asz;
tlb->seg = seg;
tlb->acc = acc;
tlb->start = addr0;
tlb->end = addr0 + szmax;
tlb->base = ptr - addr0;
}
fast:
if(acc == ACCW)
switch(sz){
case 1: PUT8(ptr, 0, *val); break;
case 2: PUT16(ptr, 0, *val); break;
case 4: PUT32(ptr, 0, *val); break;
case 8: PUT64(ptr, 0, *val); break;
}
else
switch(sz){
case 1: *val = GET8(ptr, 0); break;
case 2: *val = GET16(ptr, 0); break;
case 4: *val = GET32(ptr, 0); break;
case 8: *val = GET64(ptr, 0); break;
}
}else{
slow:
if(acc != ACCW)
*val = 0;
for(i = 0; i < sz; i++){
ptr = gptr(pa[i], 1);
if(ptr == nil)
vmerror("x86access: access to unmapped address %#p", pa[i]);
else if(acc == ACCW)
*ptr = GET8(val, i);
else
PUT8(val, i, *ptr);
}
}
return 0;
}