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mirror_qemu/target/i386/tcg/sysemu/excp_helper.c

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/*
* x86 exception helpers - sysemu code
*
* Copyright (c) 2003 Fabrice Bellard
*
* 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 2.1 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, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/cpu_ldst.h"
#include "exec/exec-all.h"
#include "tcg/helper-tcg.h"
typedef struct TranslateParams {
target_ulong addr;
target_ulong cr3;
int pg_mode;
int mmu_idx;
int ptw_idx;
MMUAccessType access_type;
} TranslateParams;
typedef struct TranslateResult {
hwaddr paddr;
int prot;
int page_size;
} TranslateResult;
typedef enum TranslateFaultStage2 {
S2_NONE,
S2_GPA,
S2_GPT,
} TranslateFaultStage2;
typedef struct TranslateFault {
int exception_index;
int error_code;
target_ulong cr2;
TranslateFaultStage2 stage2;
} TranslateFault;
typedef struct PTETranslate {
CPUX86State *env;
TranslateFault *err;
int ptw_idx;
void *haddr;
hwaddr gaddr;
} PTETranslate;
static bool ptw_translate(PTETranslate *inout, hwaddr addr)
{
CPUTLBEntryFull *full;
int flags;
inout->gaddr = addr;
flags = probe_access_full(inout->env, addr, 0, MMU_DATA_STORE,
inout->ptw_idx, true, &inout->haddr, &full, 0);
if (unlikely(flags & TLB_INVALID_MASK)) {
TranslateFault *err = inout->err;
assert(inout->ptw_idx == MMU_NESTED_IDX);
*err = (TranslateFault){
.error_code = inout->env->error_code,
.cr2 = addr,
.stage2 = S2_GPT,
};
return false;
}
return true;
}
static inline uint32_t ptw_ldl(const PTETranslate *in)
{
if (likely(in->haddr)) {
return ldl_p(in->haddr);
}
return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0);
}
static inline uint64_t ptw_ldq(const PTETranslate *in)
{
if (likely(in->haddr)) {
return ldq_p(in->haddr);
}
return cpu_ldq_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0);
}
/*
* Note that we can use a 32-bit cmpxchg for all page table entries,
* even 64-bit ones, because PG_PRESENT_MASK, PG_ACCESSED_MASK and
* PG_DIRTY_MASK are all in the low 32 bits.
*/
static bool ptw_setl_slow(const PTETranslate *in, uint32_t old, uint32_t new)
{
uint32_t cmp;
/* Does x86 really perform a rmw cycle on mmio for ptw? */
start_exclusive();
cmp = cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0);
if (cmp == old) {
cpu_stl_mmuidx_ra(in->env, in->gaddr, new, in->ptw_idx, 0);
}
end_exclusive();
return cmp == old;
}
static inline bool ptw_setl(const PTETranslate *in, uint32_t old, uint32_t set)
{
if (set & ~old) {
uint32_t new = old | set;
if (likely(in->haddr)) {
old = cpu_to_le32(old);
new = cpu_to_le32(new);
return qatomic_cmpxchg((uint32_t *)in->haddr, old, new) == old;
}
return ptw_setl_slow(in, old, new);
}
return true;
}
static bool mmu_translate(CPUX86State *env, const TranslateParams *in,
TranslateResult *out, TranslateFault *err)
{
const int32_t a20_mask = x86_get_a20_mask(env);
const target_ulong addr = in->addr;
const int pg_mode = in->pg_mode;
const bool is_user = (in->mmu_idx == MMU_USER_IDX);
const MMUAccessType access_type = in->access_type;
uint64_t ptep, pte, rsvd_mask;
PTETranslate pte_trans = {
.env = env,
.err = err,
.ptw_idx = in->ptw_idx,
};
hwaddr pte_addr, paddr;
uint32_t pkr;
int page_size;
int error_code;
restart_all:
rsvd_mask = ~MAKE_64BIT_MASK(0, env_archcpu(env)->phys_bits);
rsvd_mask &= PG_ADDRESS_MASK;
if (!(pg_mode & PG_MODE_NXE)) {
rsvd_mask |= PG_NX_MASK;
}
if (pg_mode & PG_MODE_PAE) {
#ifdef TARGET_X86_64
if (pg_mode & PG_MODE_LMA) {
if (pg_mode & PG_MODE_LA57) {
/*
* Page table level 5
*/
pte_addr = ((in->cr3 & ~0xfff) +
(((addr >> 48) & 0x1ff) << 3)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
restart_5:
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & (rsvd_mask | PG_PSE_MASK)) {
goto do_fault_rsvd;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_5;
}
ptep = pte ^ PG_NX_MASK;
} else {
pte = in->cr3;
ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK;
}
/*
* Page table level 4
*/
pte_addr = ((pte & PG_ADDRESS_MASK) +
(((addr >> 39) & 0x1ff) << 3)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
restart_4:
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & (rsvd_mask | PG_PSE_MASK)) {
goto do_fault_rsvd;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_4;
}
ptep &= pte ^ PG_NX_MASK;
/*
* Page table level 3
*/
pte_addr = ((pte & PG_ADDRESS_MASK) +
(((addr >> 30) & 0x1ff) << 3)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
restart_3_lma:
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & rsvd_mask) {
goto do_fault_rsvd;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_3_lma;
}
ptep &= pte ^ PG_NX_MASK;
if (pte & PG_PSE_MASK) {
/* 1 GB page */
page_size = 1024 * 1024 * 1024;
goto do_check_protect;
}
} else
#endif
{
/*
* Page table level 3
*/
pte_addr = ((in->cr3 & ~0x1f) + ((addr >> 27) & 0x18)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
rsvd_mask |= PG_HI_USER_MASK;
restart_3_nolma:
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & (rsvd_mask | PG_NX_MASK)) {
goto do_fault_rsvd;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_3_nolma;
}
ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK;
}
/*
* Page table level 2
*/
pte_addr = ((pte & PG_ADDRESS_MASK) +
(((addr >> 21) & 0x1ff) << 3)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
restart_2_pae:
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & rsvd_mask) {
goto do_fault_rsvd;
}
if (pte & PG_PSE_MASK) {
/* 2 MB page */
page_size = 2048 * 1024;
ptep &= pte ^ PG_NX_MASK;
goto do_check_protect;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_2_pae;
}
ptep &= pte ^ PG_NX_MASK;
/*
* Page table level 1
*/
pte_addr = ((pte & PG_ADDRESS_MASK) +
(((addr >> 12) & 0x1ff) << 3)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
pte = ptw_ldq(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pte & rsvd_mask) {
goto do_fault_rsvd;
}
/* combine pde and pte nx, user and rw protections */
ptep &= pte ^ PG_NX_MASK;
page_size = 4096;
} else {
/*
* Page table level 2
*/
pte_addr = ((in->cr3 & ~0xfff) + ((addr >> 20) & 0xffc)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
restart_2_nopae:
pte = ptw_ldl(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
ptep = pte | PG_NX_MASK;
/* if PSE bit is set, then we use a 4MB page */
if ((pte & PG_PSE_MASK) && (pg_mode & PG_MODE_PSE)) {
page_size = 4096 * 1024;
/*
* Bits 20-13 provide bits 39-32 of the address, bit 21 is reserved.
* Leave bits 20-13 in place for setting accessed/dirty bits below.
*/
pte = (uint32_t)pte | ((pte & 0x1fe000LL) << (32 - 13));
rsvd_mask = 0x200000;
goto do_check_protect_pse36;
}
if (!ptw_setl(&pte_trans, pte, PG_ACCESSED_MASK)) {
goto restart_2_nopae;
}
/*
* Page table level 1
*/
pte_addr = ((pte & ~0xfffu) + ((addr >> 10) & 0xffc)) & a20_mask;
if (!ptw_translate(&pte_trans, pte_addr)) {
return false;
}
pte = ptw_ldl(&pte_trans);
if (!(pte & PG_PRESENT_MASK)) {
goto do_fault;
}
/* combine pde and pte user and rw protections */
ptep &= pte | PG_NX_MASK;
page_size = 4096;
rsvd_mask = 0;
}
do_check_protect:
rsvd_mask |= (page_size - 1) & PG_ADDRESS_MASK & ~PG_PSE_PAT_MASK;
do_check_protect_pse36:
if (pte & rsvd_mask) {
goto do_fault_rsvd;
}
ptep ^= PG_NX_MASK;
/* can the page can be put in the TLB? prot will tell us */
if (is_user && !(ptep & PG_USER_MASK)) {
goto do_fault_protect;
}
int prot = 0;
if (in->mmu_idx != MMU_KSMAP_IDX || !(ptep & PG_USER_MASK)) {
prot |= PAGE_READ;
if ((ptep & PG_RW_MASK) || !(is_user || (pg_mode & PG_MODE_WP))) {
prot |= PAGE_WRITE;
}
}
if (!(ptep & PG_NX_MASK) &&
(is_user ||
!((pg_mode & PG_MODE_SMEP) && (ptep & PG_USER_MASK)))) {
prot |= PAGE_EXEC;
}
if (ptep & PG_USER_MASK) {
pkr = pg_mode & PG_MODE_PKE ? env->pkru : 0;
} else {
pkr = pg_mode & PG_MODE_PKS ? env->pkrs : 0;
}
if (pkr) {
uint32_t pk = (pte & PG_PKRU_MASK) >> PG_PKRU_BIT;
uint32_t pkr_ad = (pkr >> pk * 2) & 1;
uint32_t pkr_wd = (pkr >> pk * 2) & 2;
uint32_t pkr_prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
if (pkr_ad) {
pkr_prot &= ~(PAGE_READ | PAGE_WRITE);
} else if (pkr_wd && (is_user || (pg_mode & PG_MODE_WP))) {
pkr_prot &= ~PAGE_WRITE;
}
if ((pkr_prot & (1 << access_type)) == 0) {
goto do_fault_pk_protect;
}
prot &= pkr_prot;
}
if ((prot & (1 << access_type)) == 0) {
goto do_fault_protect;
}
/* yes, it can! */
{
uint32_t set = PG_ACCESSED_MASK;
if (access_type == MMU_DATA_STORE) {
set |= PG_DIRTY_MASK;
} else if (!(pte & PG_DIRTY_MASK)) {
/*
* Only set write access if already dirty...
* otherwise wait for dirty access.
*/
prot &= ~PAGE_WRITE;
}
if (!ptw_setl(&pte_trans, pte, set)) {
/*
* We can arrive here from any of 3 levels and 2 formats.
* The only safe thing is to restart the entire lookup.
*/
goto restart_all;
}
}
/* align to page_size */
paddr = (pte & a20_mask & PG_ADDRESS_MASK & ~(page_size - 1))
| (addr & (page_size - 1));
if (in->ptw_idx == MMU_NESTED_IDX) {
CPUTLBEntryFull *full;
int flags, nested_page_size;
flags = probe_access_full(env, paddr, 0, access_type,
MMU_NESTED_IDX, true,
&pte_trans.haddr, &full, 0);
if (unlikely(flags & TLB_INVALID_MASK)) {
*err = (TranslateFault){
.error_code = env->error_code,
.cr2 = paddr,
.stage2 = S2_GPA,
};
return false;
}
/* Merge stage1 & stage2 protection bits. */
prot &= full->prot;
/* Re-verify resulting protection. */
if ((prot & (1 << access_type)) == 0) {
goto do_fault_protect;
}
/* Merge stage1 & stage2 addresses to final physical address. */
nested_page_size = 1 << full->lg_page_size;
paddr = (full->phys_addr & ~(nested_page_size - 1))
| (paddr & (nested_page_size - 1));
/*
* Use the larger of stage1 & stage2 page sizes, so that
* invalidation works.
*/
if (nested_page_size > page_size) {
page_size = nested_page_size;
}
}
out->paddr = paddr;
out->prot = prot;
out->page_size = page_size;
return true;
do_fault_rsvd:
error_code = PG_ERROR_RSVD_MASK;
goto do_fault_cont;
do_fault_protect:
error_code = PG_ERROR_P_MASK;
goto do_fault_cont;
do_fault_pk_protect:
assert(access_type != MMU_INST_FETCH);
error_code = PG_ERROR_PK_MASK | PG_ERROR_P_MASK;
goto do_fault_cont;
do_fault:
error_code = 0;
do_fault_cont:
if (is_user) {
error_code |= PG_ERROR_U_MASK;
}
switch (access_type) {
case MMU_DATA_LOAD:
break;
case MMU_DATA_STORE:
error_code |= PG_ERROR_W_MASK;
break;
case MMU_INST_FETCH:
if (pg_mode & (PG_MODE_NXE | PG_MODE_SMEP)) {
error_code |= PG_ERROR_I_D_MASK;
}
break;
}
*err = (TranslateFault){
.exception_index = EXCP0E_PAGE,
.error_code = error_code,
.cr2 = addr,
};
return false;
}
static G_NORETURN void raise_stage2(CPUX86State *env, TranslateFault *err,
uintptr_t retaddr)
{
uint64_t exit_info_1 = err->error_code;
switch (err->stage2) {
case S2_GPT:
exit_info_1 |= SVM_NPTEXIT_GPT;
break;
case S2_GPA:
exit_info_1 |= SVM_NPTEXIT_GPA;
break;
default:
g_assert_not_reached();
}
x86_stq_phys(env_cpu(env),
env->vm_vmcb + offsetof(struct vmcb, control.exit_info_2),
err->cr2);
cpu_vmexit(env, SVM_EXIT_NPF, exit_info_1, retaddr);
}
static bool get_physical_address(CPUX86State *env, vaddr addr,
MMUAccessType access_type, int mmu_idx,
TranslateResult *out, TranslateFault *err)
{
TranslateParams in;
bool use_stage2 = env->hflags2 & HF2_NPT_MASK;
in.addr = addr;
in.access_type = access_type;
switch (mmu_idx) {
case MMU_PHYS_IDX:
break;
case MMU_NESTED_IDX:
if (likely(use_stage2)) {
in.cr3 = env->nested_cr3;
in.pg_mode = env->nested_pg_mode;
in.mmu_idx = MMU_USER_IDX;
in.ptw_idx = MMU_PHYS_IDX;
if (!mmu_translate(env, &in, out, err)) {
err->stage2 = S2_GPA;
return false;
}
return true;
}
break;
default:
if (likely(env->cr[0] & CR0_PG_MASK)) {
in.cr3 = env->cr[3];
in.mmu_idx = mmu_idx;
in.ptw_idx = use_stage2 ? MMU_NESTED_IDX : MMU_PHYS_IDX;
in.pg_mode = get_pg_mode(env);
if (in.pg_mode & PG_MODE_LMA) {
/* test virtual address sign extension */
int shift = in.pg_mode & PG_MODE_LA57 ? 56 : 47;
int64_t sext = (int64_t)addr >> shift;
if (sext != 0 && sext != -1) {
*err = (TranslateFault){
.exception_index = EXCP0D_GPF,
.cr2 = addr,
};
return false;
}
}
return mmu_translate(env, &in, out, err);
}
break;
}
/* Translation disabled. */
out->paddr = addr & x86_get_a20_mask(env);
#ifdef TARGET_X86_64
if (!(env->hflags & HF_LMA_MASK)) {
/* Without long mode we can only address 32bits in real mode */
out->paddr = (uint32_t)out->paddr;
}
#endif
out->prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
out->page_size = TARGET_PAGE_SIZE;
return true;
}
bool x86_cpu_tlb_fill(CPUState *cs, vaddr addr, int size,
MMUAccessType access_type, int mmu_idx,
bool probe, uintptr_t retaddr)
{
CPUX86State *env = cpu_env(cs);
TranslateResult out;
TranslateFault err;
if (get_physical_address(env, addr, access_type, mmu_idx, &out, &err)) {
/*
* Even if 4MB pages, we map only one 4KB page in the cache to
* avoid filling it too fast.
*/
assert(out.prot & (1 << access_type));
tlb_set_page_with_attrs(cs, addr & TARGET_PAGE_MASK,
out.paddr & TARGET_PAGE_MASK,
cpu_get_mem_attrs(env),
out.prot, mmu_idx, out.page_size);
return true;
}
if (probe) {
/* This will be used if recursing for stage2 translation. */
env->error_code = err.error_code;
return false;
}
if (err.stage2 != S2_NONE) {
raise_stage2(env, &err, retaddr);
}
if (env->intercept_exceptions & (1 << err.exception_index)) {
/* cr2 is not modified in case of exceptions */
x86_stq_phys(cs, env->vm_vmcb +
offsetof(struct vmcb, control.exit_info_2),
err.cr2);
} else {
env->cr[2] = err.cr2;
}
raise_exception_err_ra(env, err.exception_index, err.error_code, retaddr);
}
G_NORETURN void x86_cpu_do_unaligned_access(CPUState *cs, vaddr vaddr,
MMUAccessType access_type,
int mmu_idx, uintptr_t retaddr)
{
X86CPU *cpu = X86_CPU(cs);
handle_unaligned_access(&cpu->env, vaddr, access_type, retaddr);
}
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