Bochs/bochs/cpu/access.cc
Stanislav Shwartsman eda28b95f4 unfortunately this change is rquired to make SMAP and SMEP features to work.
I observed ~5% emulation slowdown ... thinking about possible mitigations

this fixes TLB issue with SMAP and SMEP features.
these features introduce a new behavior when page can be inaccessible by System (CPL=0).
Current behavior is accessBits was not supporting it but legacy (from Bochs 2.3.6) was.
The wrong behavior can be observed if user access a user page and system access the same page later.
user access is fine and pass SMEP/SMA checks and stores the translation in TLB.
the system access will hit the TLB and nobody could detect that system cannot access that page.
2013-01-16 17:28:20 +00:00

515 lines
16 KiB
C++

/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2005-2010 The Bochs Project
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
//
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
bx_address bx_asize_mask[] = {
0xffff, // as16 (asize = '00)
0xffffffff, // as32 (asize = '01)
#if BX_SUPPORT_X86_64
BX_CONST64(0xffffffffffffffff), // as64 (asize = '10)
BX_CONST64(0xffffffffffffffff) // as64 (asize = '11)
#endif
};
bx_bool BX_CPP_AttrRegparmN(3)
BX_CPU_C::write_virtual_checks(bx_segment_reg_t *seg, Bit32u offset, unsigned length)
{
Bit32u upper_limit;
if (seg->cache.valid==0) {
BX_DEBUG(("write_virtual_checks(): segment descriptor not valid"));
return 0;
}
if (seg->cache.p == 0) { /* not present */
BX_ERROR(("write_virtual_checks(): segment not present"));
return 0;
}
length--;
switch (seg->cache.type) {
case 0: case 1: // read only
case 4: case 5: // read only, expand down
case 8: case 9: // execute only
case 10: case 11: // execute/read
case 12: case 13: // execute only, conforming
case 14: case 15: // execute/read-only, conforming
BX_ERROR(("write_virtual_checks(): no write access to seg"));
return 0;
case 2: case 3: /* read/write */
if (offset > (seg->cache.u.segment.limit_scaled - length)
|| length > seg->cache.u.segment.limit_scaled)
{
BX_ERROR(("write_virtual_checks(): write beyond limit, r/w"));
return 0;
}
if (seg->cache.u.segment.limit_scaled >= 31) {
// Mark cache as being OK type for succeeding read/writes. The limit
// checks still needs to be done though, but is more simple. We
// could probably also optimize that out with a flag for the case
// when limit is the maximum 32bit value. Limit should accomodate
// at least a dword, since we subtract from it in the simple
// limit check in other functions, and we don't want the value to roll.
// Only normal segments (not expand down) are handled this way.
seg->cache.valid |= SegAccessROK | SegAccessWOK;
}
break;
case 6: case 7: /* read/write, expand down */
if (seg->cache.u.segment.d_b)
upper_limit = 0xffffffff;
else
upper_limit = 0x0000ffff;
if (offset <= seg->cache.u.segment.limit_scaled ||
offset > upper_limit || (upper_limit - offset) < length)
{
BX_ERROR(("write_virtual_checks(): write beyond limit, r/w ED"));
return 0;
}
break;
default:
BX_PANIC(("write_virtual_checks(): unknown descriptor type=%d", seg->cache.type));
}
return 1;
}
bx_bool BX_CPP_AttrRegparmN(3)
BX_CPU_C::read_virtual_checks(bx_segment_reg_t *seg, Bit32u offset, unsigned length)
{
Bit32u upper_limit;
if (seg->cache.valid==0) {
BX_DEBUG(("read_virtual_checks(): segment descriptor not valid"));
return 0;
}
if (seg->cache.p == 0) { /* not present */
BX_ERROR(("read_virtual_checks(): segment not present"));
return 0;
}
length--;
switch (seg->cache.type) {
case 0: case 1: /* read only */
case 2: case 3: /* read/write */
case 10: case 11: /* execute/read */
case 14: case 15: /* execute/read-only, conforming */
if (offset > (seg->cache.u.segment.limit_scaled - length)
|| length > seg->cache.u.segment.limit_scaled)
{
BX_ERROR(("read_virtual_checks(): read beyond limit"));
return 0;
}
if (seg->cache.u.segment.limit_scaled >= 31) {
// Mark cache as being OK type for succeeding reads. See notes for
// write checks; similar code.
seg->cache.valid |= SegAccessROK;
}
break;
case 4: case 5: /* read only, expand down */
case 6: case 7: /* read/write, expand down */
if (seg->cache.u.segment.d_b)
upper_limit = 0xffffffff;
else
upper_limit = 0x0000ffff;
if (offset <= seg->cache.u.segment.limit_scaled ||
offset > upper_limit || (upper_limit - offset) < length)
{
BX_ERROR(("read_virtual_checks(): read beyond limit ED"));
return 0;
}
break;
case 8: case 9: /* execute only */
case 12: case 13: /* execute only, conforming */
/* can't read or write an execute-only segment */
BX_ERROR(("read_virtual_checks(): execute only"));
return 0;
default:
BX_PANIC(("read_virtual_checks(): unknown descriptor type=%d", seg->cache.type));
}
return 1;
}
bx_bool BX_CPP_AttrRegparmN(3)
BX_CPU_C::execute_virtual_checks(bx_segment_reg_t *seg, Bit32u offset, unsigned length)
{
Bit32u upper_limit;
if (seg->cache.valid==0) {
BX_DEBUG(("execute_virtual_checks(): segment descriptor not valid"));
return 0;
}
if (seg->cache.p == 0) { /* not present */
BX_ERROR(("execute_virtual_checks(): segment not present"));
return 0;
}
length--;
switch (seg->cache.type) {
case 0: case 1: /* read only */
case 2: case 3: /* read/write */
case 10: case 11: /* execute/read */
case 14: case 15: /* execute/read-only, conforming */
if (offset > (seg->cache.u.segment.limit_scaled - length)
|| length > seg->cache.u.segment.limit_scaled)
{
BX_ERROR(("execute_virtual_checks(): read beyond limit"));
return 0;
}
if (seg->cache.u.segment.limit_scaled >= 31) {
// Mark cache as being OK type for succeeding reads. See notes for
// write checks; similar code.
seg->cache.valid |= SegAccessROK;
}
break;
case 8: case 9: /* execute only */
case 12: case 13: /* execute only, conforming */
if (offset > (seg->cache.u.segment.limit_scaled - length)
|| length > seg->cache.u.segment.limit_scaled)
{
BX_ERROR(("execute_virtual_checks(): read beyond limit execute only"));
return 0;
}
break;
case 4: case 5: /* read only, expand down */
case 6: case 7: /* read/write, expand down */
if (seg->cache.u.segment.d_b)
upper_limit = 0xffffffff;
else
upper_limit = 0x0000ffff;
if (offset <= seg->cache.u.segment.limit_scaled ||
offset > upper_limit || (upper_limit - offset) < length)
{
BX_ERROR(("execute_virtual_checks(): read beyond limit ED"));
return 0;
}
break;
default:
BX_PANIC(("execute_virtual_checks(): unknown descriptor type=%d", seg->cache.type));
}
return 1;
}
const char *BX_CPU_C::strseg(bx_segment_reg_t *seg)
{
if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES]) return("ES");
else if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS]) return("CS");
else if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS]) return("SS");
else if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS]) return("DS");
else if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS]) return("FS");
else if (seg == &BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS]) return("GS");
else {
BX_PANIC(("undefined segment passed to strseg()!"));
return("??");
}
}
int BX_CPU_C::int_number(unsigned s)
{
if (s == BX_SEG_REG_SS)
return BX_SS_EXCEPTION;
else
return BX_GP_EXCEPTION;
}
Bit8u BX_CPP_AttrRegparmN(1)
BX_CPU_C::system_read_byte(bx_address laddr)
{
Bit8u data;
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 0);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us read access
// from this CPL.
if (tlbEntry->accessBits & 0x01) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit8u *hostAddr = (Bit8u*) (hostPageAddr | pageOffset);
data = *hostAddr;
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, (tlbEntry->ppf | pageOffset), 1, 0, BX_READ, (Bit8u*) &data);
return data;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr)) {
BX_ERROR(("system_read_byte(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_read_linear(laddr, 1, 0, BX_READ, (void *) &data);
return data;
}
Bit16u BX_CPP_AttrRegparmN(1)
BX_CPU_C::system_read_word(bx_address laddr)
{
Bit16u data;
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 1);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us read access
// from this CPL.
if (tlbEntry->accessBits & 0x01) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit16u *hostAddr = (Bit16u*) (hostPageAddr | pageOffset);
ReadHostWordFromLittleEndian(hostAddr, data);
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, (tlbEntry->ppf | pageOffset), 2, 0, BX_READ, (Bit8u*) &data);
return data;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr) || ! IsCanonical(laddr+1)) {
BX_ERROR(("system_read_word(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_read_linear(laddr, 2, 0, BX_READ, (void *) &data);
return data;
}
Bit32u BX_CPP_AttrRegparmN(1)
BX_CPU_C::system_read_dword(bx_address laddr)
{
Bit32u data;
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 3);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us read access
// from this CPL.
if (tlbEntry->accessBits & 0x01) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit32u *hostAddr = (Bit32u*) (hostPageAddr | pageOffset);
ReadHostDWordFromLittleEndian(hostAddr, data);
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, (tlbEntry->ppf | pageOffset), 4, 0, BX_READ, (Bit8u*) &data);
return data;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr) || ! IsCanonical(laddr+3)) {
BX_ERROR(("system_read_dword(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_read_linear(laddr, 4, 0, BX_READ, (void *) &data);
return data;
}
Bit64u BX_CPP_AttrRegparmN(1)
BX_CPU_C::system_read_qword(bx_address laddr)
{
Bit64u data;
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 7);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us read access
// from this CPL.
if (tlbEntry->accessBits & 0x01) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit64u *hostAddr = (Bit64u*) (hostPageAddr | pageOffset);
ReadHostQWordFromLittleEndian(hostAddr, data);
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, (tlbEntry->ppf | pageOffset), 8, 0, BX_READ, (Bit8u*) &data);
return data;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr) || ! IsCanonical(laddr+7)) {
BX_ERROR(("system_read_qword(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_read_linear(laddr, 8, 0, BX_READ, (void *) &data);
return data;
}
void BX_CPP_AttrRegparmN(2)
BX_CPU_C::system_write_byte(bx_address laddr, Bit8u data)
{
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 0);
Bit32u lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us write access
// from this CPL.
if (tlbEntry->accessBits & 0x04) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
bx_phy_address pAddr = tlbEntry->ppf | pageOffset;
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, pAddr, 1, 0, BX_WRITE, (Bit8u*) &data);
Bit8u *hostAddr = (Bit8u*) (hostPageAddr | pageOffset);
pageWriteStampTable.decWriteStamp(pAddr, 1);
*hostAddr = data;
return;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr)) {
BX_ERROR(("system_write_byte(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_write_linear(laddr, 1, 0, (void *) &data);
}
void BX_CPP_AttrRegparmN(2)
BX_CPU_C::system_write_word(bx_address laddr, Bit16u data)
{
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 1);
Bit32u lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us write access
// from this CPL.
if (tlbEntry->accessBits & 0x04) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
bx_phy_address pAddr = tlbEntry->ppf | pageOffset;
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, pAddr, 2, 0, BX_WRITE, (Bit8u*) &data);
Bit16u *hostAddr = (Bit16u*) (hostPageAddr | pageOffset);
pageWriteStampTable.decWriteStamp(pAddr, 2);
WriteHostWordToLittleEndian(hostAddr, data);
return;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr) || ! IsCanonical(laddr+1)) {
BX_ERROR(("system_write_word(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_write_linear(laddr, 2, 0, (void *) &data);
}
void BX_CPP_AttrRegparmN(2)
BX_CPU_C::system_write_dword(bx_address laddr, Bit32u data)
{
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 3);
Bit32u lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us write access
// from this CPL.
if (tlbEntry->accessBits & 0x04) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
bx_phy_address pAddr = tlbEntry->ppf | pageOffset;
BX_NOTIFY_LIN_MEMORY_ACCESS(laddr, pAddr, 4, 0, BX_WRITE, (Bit8u*) &data);
Bit32u *hostAddr = (Bit32u*) (hostPageAddr | pageOffset);
pageWriteStampTable.decWriteStamp(pAddr, 4);
WriteHostDWordToLittleEndian(hostAddr, data);
return;
}
}
#if BX_SUPPORT_X86_64
if (! IsCanonical(laddr) || ! IsCanonical(laddr+3)) {
BX_ERROR(("system_write_dword(): canonical failure"));
exception(BX_GP_EXCEPTION, 0);
}
#endif
access_write_linear(laddr, 4, 0, (void *) &data);
}
Bit8u* BX_CPP_AttrRegparmN(2)
BX_CPU_C::v2h_read_byte(bx_address laddr, bx_bool user)
{
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 0);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf) {
// See if the TLB entry privilege level allows us read access
// from this CPL.
if (tlbEntry->accessBits & (0x01 << user)) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit8u *hostAddr = (Bit8u*) (hostPageAddr | pageOffset);
return hostAddr;
}
}
return 0;
}
Bit8u* BX_CPP_AttrRegparmN(2)
BX_CPU_C::v2h_write_byte(bx_address laddr, bx_bool user)
{
unsigned tlbIndex = BX_TLB_INDEX_OF(laddr, 0);
bx_address lpf = LPFOf(laddr);
bx_TLB_entry *tlbEntry = &BX_CPU_THIS_PTR TLB.entry[tlbIndex];
if (tlbEntry->lpf == lpf)
{
// See if the TLB entry privilege level allows us write access
// from this CPL.
if (tlbEntry->accessBits & (0x04 << user)) {
bx_hostpageaddr_t hostPageAddr = tlbEntry->hostPageAddr;
Bit32u pageOffset = PAGE_OFFSET(laddr);
Bit8u *hostAddr = (Bit8u*) (hostPageAddr | pageOffset);
pageWriteStampTable.decWriteStamp(tlbEntry->ppf);
return hostAddr;
}
}
return 0;
}