/*
* x86 exception helpers
*
* 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 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/exec-all.h"
#include "qemu/log.h"
#include "sysemu/sysemu.h"
#include "exec/helper-proto.h"
void helper_raise_interrupt(CPUX86State *env, int intno, int next_eip_addend)
{
raise_interrupt(env, intno, 1, 0, next_eip_addend);
}
void helper_raise_exception(CPUX86State *env, int exception_index)
{
raise_exception(env, exception_index);
}
/*
* Check nested exceptions and change to double or triple fault if
* needed. It should only be called, if this is not an interrupt.
* Returns the new exception number.
*/
static int check_exception(CPUX86State *env, int intno, int *error_code,
uintptr_t retaddr)
{
int first_contributory = env->old_exception == 0 ||
(env->old_exception >= 10 &&
env->old_exception <= 13);
int second_contributory = intno == 0 ||
(intno >= 10 && intno <= 13);
qemu_log_mask(CPU_LOG_INT, "check_exception old: 0x%x new 0x%x\n",
env->old_exception, intno);
#if !defined(CONFIG_USER_ONLY)
if (env->old_exception == EXCP08_DBLE) {
if (env->hflags & HF_SVMI_MASK) {
cpu_vmexit(env, SVM_EXIT_SHUTDOWN, 0, retaddr); /* does not return */
}
qemu_log_mask(CPU_LOG_RESET, "Triple fault\n");
qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
return EXCP_HLT;
}
#endif
if ((first_contributory && second_contributory)
|| (env->old_exception == EXCP0E_PAGE &&
(second_contributory || (intno == EXCP0E_PAGE)))) {
intno = EXCP08_DBLE;
*error_code = 0;
}
if (second_contributory || (intno == EXCP0E_PAGE) ||
(intno == EXCP08_DBLE)) {
env->old_exception = intno;
}
return intno;
}
/*
* Signal an interruption. It is executed in the main CPU loop.
* is_int is TRUE if coming from the int instruction. next_eip is the
* env->eip value AFTER the interrupt instruction. It is only relevant if
* is_int is TRUE.
*/
static void QEMU_NORETURN raise_interrupt2(CPUX86State *env, int intno,
int is_int, int error_code,
int next_eip_addend,
uintptr_t retaddr)
{
CPUState *cs = CPU(x86_env_get_cpu(env));
if (!is_int) {
cpu_svm_check_intercept_param(env, SVM_EXIT_EXCP_BASE + intno,
error_code, retaddr);
intno = check_exception(env, intno, &error_code, retaddr);
} else {
cpu_svm_check_intercept_param(env, SVM_EXIT_SWINT, 0, retaddr);
}
cs->exception_index = intno;
env->error_code = error_code;
env->exception_is_int = is_int;
env->exception_next_eip = env->eip + next_eip_addend;
cpu_loop_exit_restore(cs, retaddr);
}
/* shortcuts to generate exceptions */
void QEMU_NORETURN raise_interrupt(CPUX86State *env, int intno, int is_int,
int error_code, int next_eip_addend)
{
raise_interrupt2(env, intno, is_int, error_code, next_eip_addend, 0);
}
void raise_exception_err(CPUX86State *env, int exception_index,
int error_code)
{
raise_interrupt2(env, exception_index, 0, error_code, 0, 0);
}
void raise_exception_err_ra(CPUX86State *env, int exception_index,
int error_code, uintptr_t retaddr)
{
raise_interrupt2(env, exception_index, 0, error_code, 0, retaddr);
}
void raise_exception(CPUX86State *env, int exception_index)
{
raise_interrupt2(env, exception_index, 0, 0, 0, 0);
}
void raise_exception_ra(CPUX86State *env, int exception_index, uintptr_t retaddr)
{
raise_interrupt2(env, exception_index, 0, 0, 0, retaddr);
}
#if defined(CONFIG_USER_ONLY)
int x86_cpu_handle_mmu_fault(CPUState *cs, vaddr addr,
int is_write, int mmu_idx)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
/* user mode only emulation */
is_write &= 1;
env->cr[2] = addr;
env->error_code = (is_write << PG_ERROR_W_BIT);
env->error_code |= PG_ERROR_U_MASK;
cs->exception_index = EXCP0E_PAGE;
env->exception_is_int = 0;
env->exception_next_eip = -1;
return 1;
}
#else
/* return value:
* -1 = cannot handle fault
* 0 = nothing more to do
* 1 = generate PF fault
*/
int x86_cpu_handle_mmu_fault(CPUState *cs, vaddr addr,
int is_write1, int mmu_idx)
{
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
uint64_t ptep, pte;
int32_t a20_mask;
target_ulong pde_addr, pte_addr;
int error_code = 0;
int is_dirty, prot, page_size, is_write, is_user;
hwaddr paddr;
uint64_t rsvd_mask = PG_HI_RSVD_MASK;
uint32_t page_offset;
target_ulong vaddr;
is_user = mmu_idx == MMU_USER_IDX;
#if defined(DEBUG_MMU)
printf("MMU fault: addr=%" VADDR_PRIx " w=%d u=%d eip=" TARGET_FMT_lx "\n",
addr, is_write1, is_user, env->eip);
#endif
is_write = is_write1 & 1;
a20_mask = x86_get_a20_mask(env);
if (!(env->cr[0] & CR0_PG_MASK)) {
pte = addr;
#ifdef TARGET_X86_64
if (!(env->hflags & HF_LMA_MASK)) {
/* Without long mode we can only address 32bits in real mode */
pte = (uint32_t)pte;
}
#endif
prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
page_size = 4096;
goto do_mapping;
}
if (!(env->efer & MSR_EFER_NXE)) {
rsvd_mask |= PG_NX_MASK;
}
if (env->cr[4] & CR4_PAE_MASK) {
uint64_t pde, pdpe;
target_ulong pdpe_addr;
#ifdef TARGET_X86_64
if (env->hflags & HF_LMA_MASK) {
bool la57 = env->cr[4] & CR4_LA57_MASK;
uint64_t pml5e_addr, pml5e;
uint64_t pml4e_addr, pml4e;
int32_t sext;
/* test virtual address sign extension */
sext = la57 ? (int64_t)addr >> 56 : (int64_t)addr >> 47;
if (sext != 0 && sext != -1) {
env->error_code = 0;
cs->exception_index = EXCP0D_GPF;
return 1;
}
if (la57) {
pml5e_addr = ((env->cr[3] & ~0xfff) +
(((addr >> 48) & 0x1ff) << 3)) & a20_mask;
pml5e = x86_ldq_phys(cs, pml5e_addr);
if (!(pml5e & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pml5e & (rsvd_mask | PG_PSE_MASK)) {
goto do_fault_rsvd;
}
if (!(pml5e & PG_ACCESSED_MASK)) {
pml5e |= PG_ACCESSED_MASK;
x86_stl_phys_notdirty(cs, pml5e_addr, pml5e);
}
ptep = pml5e ^ PG_NX_MASK;
} else {
pml5e = env->cr[3];
ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK;
}
pml4e_addr = ((pml5e & PG_ADDRESS_MASK) +
(((addr >> 39) & 0x1ff) << 3)) & a20_mask;
pml4e = x86_ldq_phys(cs, pml4e_addr);
if (!(pml4e & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pml4e & (rsvd_mask | PG_PSE_MASK)) {
goto do_fault_rsvd;
}
if (!(pml4e & PG_ACCESSED_MASK)) {
pml4e |= PG_ACCESSED_MASK;
x86_stl_phys_notdirty(cs, pml4e_addr, pml4e);
}
ptep &= pml4e ^ PG_NX_MASK;
pdpe_addr = ((pml4e & PG_ADDRESS_MASK) + (((addr >> 30) & 0x1ff) << 3)) &
a20_mask;
pdpe = x86_ldq_phys(cs, pdpe_addr);
if (!(pdpe & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pdpe & rsvd_mask) {
goto do_fault_rsvd;
}
ptep &= pdpe ^ PG_NX_MASK;
if (!(pdpe & PG_ACCESSED_MASK)) {
pdpe |= PG_ACCESSED_MASK;
x86_stl_phys_notdirty(cs, pdpe_addr, pdpe);
}
if (pdpe & PG_PSE_MASK) {
/* 1 GB page */
page_size = 1024 * 1024 * 1024;
pte_addr = pdpe_addr;
pte = pdpe;
goto do_check_protect;
}
} else
#endif
{
/* XXX: load them when cr3 is loaded ? */
pdpe_addr = ((env->cr[3] & ~0x1f) + ((addr >> 27) & 0x18)) &
a20_mask;
pdpe = x86_ldq_phys(cs, pdpe_addr);
if (!(pdpe & PG_PRESENT_MASK)) {
goto do_fault;
}
rsvd_mask |= PG_HI_USER_MASK;
if (pdpe & (rsvd_mask | PG_NX_MASK)) {
goto do_fault_rsvd;
}
ptep = PG_NX_MASK | PG_USER_MASK | PG_RW_MASK;
}
pde_addr = ((pdpe & PG_ADDRESS_MASK) + (((addr >> 21) & 0x1ff) << 3)) &
a20_mask;
pde = x86_ldq_phys(cs, pde_addr);
if (!(pde & PG_PRESENT_MASK)) {
goto do_fault;
}
if (pde & rsvd_mask) {
goto do_fault_rsvd;
}
ptep &= pde ^ PG_NX_MASK;
if (pde & PG_PSE_MASK) {
/* 2 MB page */
page_size = 2048 * 1024;
pte_addr = pde_addr;
pte = pde;
goto do_check_protect;
}
/* 4 KB page */
if (!(pde & PG_ACCESSED_MASK)) {
pde |= PG_ACCESSED_MASK;
x86_stl_phys_notdirty(cs, pde_addr, pde);
}
pte_addr = ((pde & PG_ADDRESS_MASK) + (((addr >> 12) & 0x1ff) << 3)) &
a20_mask;
pte = x86_ldq_phys(cs, pte_addr);
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 {
uint32_t pde;
/* page directory entry */
pde_addr = ((env->cr[3] & ~0xfff) + ((addr >> 20) & 0xffc)) &
a20_mask;
pde = x86_ldl_phys(cs, pde_addr);
if (!(pde & PG_PRESENT_MASK)) {
goto do_fault;
}
ptep = pde | PG_NX_MASK;
/* if PSE bit is set, then we use a 4MB page */
if ((pde & PG_PSE_MASK) && (env->cr[4] & CR4_PSE_MASK)) {
page_size = 4096 * 1024;
pte_addr = pde_addr;
/* 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 = pde | ((pde & 0x1fe000LL) << (32 - 13));
rsvd_mask = 0x200000;
goto do_check_protect_pse36;
}
if (!(pde & PG_ACCESSED_MASK)) {
pde |= PG_ACCESSED_MASK;
x86_stl_phys_notdirty(cs, pde_addr, pde);
}
/* page directory entry */
pte_addr = ((pde & ~0xfff) + ((addr >> 10) & 0xffc)) &
a20_mask;
pte = x86_ldl_phys(cs, pte_addr);
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;
}
prot = 0;
if (mmu_idx != MMU_KSMAP_IDX || !(ptep & PG_USER_MASK)) {
prot |= PAGE_READ;
if ((ptep & PG_RW_MASK) || (!is_user && !(env->cr[0] & CR0_WP_MASK))) {
prot |= PAGE_WRITE;
}
}
if (!(ptep & PG_NX_MASK) &&
(mmu_idx == MMU_USER_IDX ||
!((env->cr[4] & CR4_SMEP_MASK) && (ptep & PG_USER_MASK)))) {
prot |= PAGE_EXEC;
}
if ((env->cr[4] & CR4_PKE_MASK) && (env->hflags & HF_LMA_MASK) &&
(ptep & PG_USER_MASK) && env->pkru) {
uint32_t pk = (pte & PG_PKRU_MASK) >> PG_PKRU_BIT;
uint32_t pkru_ad = (env->pkru >> pk * 2) & 1;
uint32_t pkru_wd = (env->pkru >> pk * 2) & 2;
uint32_t pkru_prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
if (pkru_ad) {
pkru_prot &= ~(PAGE_READ | PAGE_WRITE);
} else if (pkru_wd && (is_user || env->cr[0] & CR0_WP_MASK)) {
pkru_prot &= ~PAGE_WRITE;
}
prot &= pkru_prot;
if ((pkru_prot & (1 << is_write1)) == 0) {
assert(is_write1 != 2);
error_code |= PG_ERROR_PK_MASK;
goto do_fault_protect;
}
}
if ((prot & (1 << is_write1)) == 0) {
goto do_fault_protect;
}
/* yes, it can! */
is_dirty = is_write && !(pte & PG_DIRTY_MASK);
if (!(pte & PG_ACCESSED_MASK) || is_dirty) {
pte |= PG_ACCESSED_MASK;
if (is_dirty) {
pte |= PG_DIRTY_MASK;
}
x86_stl_phys_notdirty(cs, pte_addr, pte);
}
if (!(pte & PG_DIRTY_MASK)) {
/* only set write access if already dirty... otherwise wait
for dirty access */
assert(!is_write);
prot &= ~PAGE_WRITE;
}
do_mapping:
pte = pte & a20_mask;
/* align to page_size */
pte &= PG_ADDRESS_MASK & ~(page_size - 1);
/* Even if 4MB pages, we map only one 4KB page in the cache to
avoid filling it too fast */
vaddr = addr & TARGET_PAGE_MASK;
page_offset = vaddr & (page_size - 1);
paddr = pte + page_offset;
assert(prot & (1 << is_write1));
tlb_set_page_with_attrs(cs, vaddr, paddr, cpu_get_mem_attrs(env),
prot, mmu_idx, page_size);
return 0;
do_fault_rsvd:
error_code |= PG_ERROR_RSVD_MASK;
do_fault_protect:
error_code |= PG_ERROR_P_MASK;
do_fault:
error_code |= (is_write << PG_ERROR_W_BIT);
if (is_user)
error_code |= PG_ERROR_U_MASK;
if (is_write1 == 2 &&
(((env->efer & MSR_EFER_NXE) &&
(env->cr[4] & CR4_PAE_MASK)) ||
(env->cr[4] & CR4_SMEP_MASK)))
error_code |= PG_ERROR_I_D_MASK;
if (env->intercept_exceptions & (1 << EXCP0E_PAGE)) {
/* cr2 is not modified in case of exceptions */
x86_stq_phys(cs,
env->vm_vmcb + offsetof(struct vmcb, control.exit_info_2),
addr);
} else {
env->cr[2] = addr;
}
env->error_code = error_code;
cs->exception_index = EXCP0E_PAGE;
return 1;
}
#endif
