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accel/tcg: Move page_{get,set}_flags to user-exec.c

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This page tracking implementation is specific to user-only,
since the system softmmu version is in cputlb.c.  Move it
out of translate-all.c to user-exec.c.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-10-04 17:47:00 -07:00
parent 50d25c8aec
commit d941c086b8
3 changed files with 363 additions and 350 deletions
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17
accel/tcg/internal.h
View File

@ -33,6 +33,23 @@ typedef struct PageDesc {
#endif
} PageDesc;
/*
* In system mode we want L1_MAP to be based on ram offsets,
* while in user mode we want it to be based on virtual addresses.
*
* TODO: For user mode, see the caveat re host vs guest virtual
* address spaces near GUEST_ADDR_MAX.
*/
#if !defined(CONFIG_USER_ONLY)
#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS
# define L1_MAP_ADDR_SPACE_BITS HOST_LONG_BITS
#else
# define L1_MAP_ADDR_SPACE_BITS TARGET_PHYS_ADDR_SPACE_BITS
#endif
#else
# define L1_MAP_ADDR_SPACE_BITS MIN(HOST_LONG_BITS, TARGET_ABI_BITS)
#endif
/* Size of the L2 (and L3, etc) page tables. */
#define V_L2_BITS 10
#define V_L2_SIZE (1 << V_L2_BITS)

350
accel/tcg/translate-all.c
View File

@ -109,23 +109,6 @@ struct page_collection {
struct page_entry *max;
};
/*
* In system mode we want L1_MAP to be based on ram offsets,
* while in user mode we want it to be based on virtual addresses.
*
* TODO: For user mode, see the caveat re host vs guest virtual
* address spaces near GUEST_ADDR_MAX.
*/
#if !defined(CONFIG_USER_ONLY)
#if HOST_LONG_BITS < TARGET_PHYS_ADDR_SPACE_BITS
# define L1_MAP_ADDR_SPACE_BITS HOST_LONG_BITS
#else
# define L1_MAP_ADDR_SPACE_BITS TARGET_PHYS_ADDR_SPACE_BITS
#endif
#else
# define L1_MAP_ADDR_SPACE_BITS MIN(HOST_LONG_BITS, TARGET_ABI_BITS)
#endif
/* Make sure all possible CPU event bits fit in tb->trace_vcpu_dstate */
QEMU_BUILD_BUG_ON(CPU_TRACE_DSTATE_MAX_EVENTS >
sizeof_field(TranslationBlock, trace_vcpu_dstate)
@ -1170,339 +1153,6 @@ void cpu_interrupt(CPUState *cpu, int mask)
qatomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1);
}
/*
* Walks guest process memory "regions" one by one
* and calls callback function 'fn' for each region.
*/
struct walk_memory_regions_data {
walk_memory_regions_fn fn;
void *priv;
target_ulong start;
int prot;
};
static int walk_memory_regions_end(struct walk_memory_regions_data *data,
target_ulong end, int new_prot)
{
if (data->start != -1u) {
int rc = data->fn(data->priv, data->start, end, data->prot);
if (rc != 0) {
return rc;
}
}
data->start = (new_prot ? end : -1u);
data->prot = new_prot;
return 0;
}
static int walk_memory_regions_1(struct walk_memory_regions_data *data,
target_ulong base, int level, void **lp)
{
target_ulong pa;
int i, rc;
if (*lp == NULL) {
return walk_memory_regions_end(data, base, 0);
}
if (level == 0) {
PageDesc *pd = *lp;
for (i = 0; i < V_L2_SIZE; ++i) {
int prot = pd[i].flags;
pa = base | (i << TARGET_PAGE_BITS);
if (prot != data->prot) {
rc = walk_memory_regions_end(data, pa, prot);
if (rc != 0) {
return rc;
}
}
}
} else {
void **pp = *lp;
for (i = 0; i < V_L2_SIZE; ++i) {
pa = base | ((target_ulong)i <<
(TARGET_PAGE_BITS + V_L2_BITS * level));
rc = walk_memory_regions_1(data, pa, level - 1, pp + i);
if (rc != 0) {
return rc;
}
}
}
return 0;
}
int walk_memory_regions(void *priv, walk_memory_regions_fn fn)
{
struct walk_memory_regions_data data;
uintptr_t i, l1_sz = v_l1_size;
data.fn = fn;
data.priv = priv;
data.start = -1u;
data.prot = 0;
for (i = 0; i < l1_sz; i++) {
target_ulong base = i << (v_l1_shift + TARGET_PAGE_BITS);
int rc = walk_memory_regions_1(&data, base, v_l2_levels, l1_map + i);
if (rc != 0) {
return rc;
}
}
return walk_memory_regions_end(&data, 0, 0);
}
static int dump_region(void *priv, target_ulong start,
target_ulong end, unsigned long prot)
{
FILE *f = (FILE *)priv;
(void) fprintf(f, TARGET_FMT_lx"-"TARGET_FMT_lx
" "TARGET_FMT_lx" %c%c%c\n",
start, end, end - start,
((prot & PAGE_READ) ? 'r' : '-'),
((prot & PAGE_WRITE) ? 'w' : '-'),
((prot & PAGE_EXEC) ? 'x' : '-'));
return 0;
}
/* dump memory mappings */
void page_dump(FILE *f)
{
const int length = sizeof(target_ulong) * 2;
(void) fprintf(f, "%-*s %-*s %-*s %s\n",
length, "start", length, "end", length, "size", "prot");
walk_memory_regions(f, dump_region);
}
int page_get_flags(target_ulong address)
{
PageDesc *p;
p = page_find(address >> TARGET_PAGE_BITS);
if (!p) {
return 0;
}
return p->flags;
}
/*
* Allow the target to decide if PAGE_TARGET_[12] may be reset.
* By default, they are not kept.
*/
#ifndef PAGE_TARGET_STICKY
#define PAGE_TARGET_STICKY 0
#endif
#define PAGE_STICKY (PAGE_ANON | PAGE_PASSTHROUGH | PAGE_TARGET_STICKY)
/* Modify the flags of a page and invalidate the code if necessary.
The flag PAGE_WRITE_ORG is positioned automatically depending
on PAGE_WRITE. The mmap_lock should already be held. */
void page_set_flags(target_ulong start, target_ulong end, int flags)
{
target_ulong addr, len;
bool reset, inval_tb = false;
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
a missing call to h2g_valid. */
assert(end - 1 <= GUEST_ADDR_MAX);
assert(start < end);
/* Only set PAGE_ANON with new mappings. */
assert(!(flags & PAGE_ANON) || (flags & PAGE_RESET));
assert_memory_lock();
start = start & TARGET_PAGE_MASK;
end = TARGET_PAGE_ALIGN(end);
if (flags & PAGE_WRITE) {
flags |= PAGE_WRITE_ORG;
}
reset = !(flags & PAGE_VALID) || (flags & PAGE_RESET);
if (reset) {
page_reset_target_data(start, end);
}
flags &= ~PAGE_RESET;
for (addr = start, len = end - start;
len != 0;
len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
PageDesc *p = page_find_alloc(addr >> TARGET_PAGE_BITS, true);
/*
* If the page was executable, but is reset, or is no longer
* executable, or has become writable, then invalidate any code.
*/
if ((p->flags & PAGE_EXEC)
&& (reset ||
!(flags & PAGE_EXEC) ||
(flags & ~p->flags & PAGE_WRITE))) {
inval_tb = true;
}
/* Using mprotect on a page does not change sticky bits. */
p->flags = (reset ? 0 : p->flags & PAGE_STICKY) | flags;
}
if (inval_tb) {
tb_invalidate_phys_range(start, end);
}
}
int page_check_range(target_ulong start, target_ulong len, int flags)
{
PageDesc *p;
target_ulong end;
target_ulong addr;
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
a missing call to h2g_valid. */
if (TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS) {
assert(start < ((target_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
}
if (len == 0) {
return 0;
}
if (start + len - 1 < start) {
/* We've wrapped around. */
return -1;
}
/* must do before we loose bits in the next step */
end = TARGET_PAGE_ALIGN(start + len);
start = start & TARGET_PAGE_MASK;
for (addr = start, len = end - start;
len != 0;
len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
if (!p) {
return -1;
}
if (!(p->flags & PAGE_VALID)) {
return -1;
}
if ((flags & PAGE_READ) && !(p->flags & PAGE_READ)) {
return -1;
}
if (flags & PAGE_WRITE) {
if (!(p->flags & PAGE_WRITE_ORG)) {
return -1;
}
/* unprotect the page if it was put read-only because it
contains translated code */
if (!(p->flags & PAGE_WRITE)) {
if (!page_unprotect(addr, 0)) {
return -1;
}
}
}
}
return 0;
}
void page_protect(tb_page_addr_t page_addr)
{
target_ulong addr;
PageDesc *p;
int prot;
p = page_find(page_addr >> TARGET_PAGE_BITS);
if (p && (p->flags & PAGE_WRITE)) {
/*
* Force the host page as non writable (writes will have a page fault +
* mprotect overhead).
*/
page_addr &= qemu_host_page_mask;
prot = 0;
for (addr = page_addr; addr < page_addr + qemu_host_page_size;
addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
if (!p) {
continue;
}
prot |= p->flags;
p->flags &= ~PAGE_WRITE;
}
mprotect(g2h_untagged(page_addr), qemu_host_page_size,
(prot & PAGE_BITS) & ~PAGE_WRITE);
}
}
/* called from signal handler: invalidate the code and unprotect the
* page. Return 0 if the fault was not handled, 1 if it was handled,
* and 2 if it was handled but the caller must cause the TB to be
* immediately exited. (We can only return 2 if the 'pc' argument is
* non-zero.)
*/
int page_unprotect(target_ulong address, uintptr_t pc)
{
unsigned int prot;
bool current_tb_invalidated;
PageDesc *p;
target_ulong host_start, host_end, addr;
/* Technically this isn't safe inside a signal handler. However we
know this only ever happens in a synchronous SEGV handler, so in
practice it seems to be ok. */
mmap_lock();
p = page_find(address >> TARGET_PAGE_BITS);
if (!p) {
mmap_unlock();
return 0;
}
/* if the page was really writable, then we change its
protection back to writable */
if (p->flags & PAGE_WRITE_ORG) {
current_tb_invalidated = false;
if (p->flags & PAGE_WRITE) {
/* If the page is actually marked WRITE then assume this is because
* this thread raced with another one which got here first and
* set the page to PAGE_WRITE and did the TB invalidate for us.
*/
#ifdef TARGET_HAS_PRECISE_SMC
TranslationBlock *current_tb = tcg_tb_lookup(pc);
if (current_tb) {
current_tb_invalidated = tb_cflags(current_tb) & CF_INVALID;
}
#endif
} else {
host_start = address & qemu_host_page_mask;
host_end = host_start + qemu_host_page_size;
prot = 0;
for (addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
p->flags |= PAGE_WRITE;
prot |= p->flags;
/* and since the content will be modified, we must invalidate
the corresponding translated code. */
current_tb_invalidated |=
tb_invalidate_phys_page_unwind(addr, pc);
}
mprotect((void *)g2h_untagged(host_start), qemu_host_page_size,
prot & PAGE_BITS);
}
mmap_unlock();
/* If current TB was invalidated return to main loop */
return current_tb_invalidated ? 2 : 1;
}
mmap_unlock();
return 0;
}
#endif /* CONFIG_USER_ONLY */
/*

346
accel/tcg/user-exec.c
View File

@ -135,6 +135,352 @@ bool handle_sigsegv_accerr_write(CPUState *cpu, sigset_t *old_set,
}
}
/*
* Walks guest process memory "regions" one by one
* and calls callback function 'fn' for each region.
*/
struct walk_memory_regions_data {
walk_memory_regions_fn fn;
void *priv;
target_ulong start;
int prot;
};
static int walk_memory_regions_end(struct walk_memory_regions_data *data,
target_ulong end, int new_prot)
{
if (data->start != -1u) {
int rc = data->fn(data->priv, data->start, end, data->prot);
if (rc != 0) {
return rc;
}
}
data->start = (new_prot ? end : -1u);
data->prot = new_prot;
return 0;
}
static int walk_memory_regions_1(struct walk_memory_regions_data *data,
target_ulong base, int level, void **lp)
{
target_ulong pa;
int i, rc;
if (*lp == NULL) {
return walk_memory_regions_end(data, base, 0);
}
if (level == 0) {
PageDesc *pd = *lp;
for (i = 0; i < V_L2_SIZE; ++i) {
int prot = pd[i].flags;
pa = base | (i << TARGET_PAGE_BITS);
if (prot != data->prot) {
rc = walk_memory_regions_end(data, pa, prot);
if (rc != 0) {
return rc;
}
}
}
} else {
void **pp = *lp;
for (i = 0; i < V_L2_SIZE; ++i) {
pa = base | ((target_ulong)i <<
(TARGET_PAGE_BITS + V_L2_BITS * level));
rc = walk_memory_regions_1(data, pa, level - 1, pp + i);
if (rc != 0) {
return rc;
}
}
}
return 0;
}
int walk_memory_regions(void *priv, walk_memory_regions_fn fn)
{
struct walk_memory_regions_data data;
uintptr_t i, l1_sz = v_l1_size;
data.fn = fn;
data.priv = priv;
data.start = -1u;
data.prot = 0;
for (i = 0; i < l1_sz; i++) {
target_ulong base = i << (v_l1_shift + TARGET_PAGE_BITS);
int rc = walk_memory_regions_1(&data, base, v_l2_levels, l1_map + i);
if (rc != 0) {
return rc;
}
}
return walk_memory_regions_end(&data, 0, 0);
}
static int dump_region(void *priv, target_ulong start,
target_ulong end, unsigned long prot)
{
FILE *f = (FILE *)priv;
(void) fprintf(f, TARGET_FMT_lx"-"TARGET_FMT_lx
" "TARGET_FMT_lx" %c%c%c\n",
start, end, end - start,
((prot & PAGE_READ) ? 'r' : '-'),
((prot & PAGE_WRITE) ? 'w' : '-'),
((prot & PAGE_EXEC) ? 'x' : '-'));
return 0;
}
/* dump memory mappings */
void page_dump(FILE *f)
{
const int length = sizeof(target_ulong) * 2;
(void) fprintf(f, "%-*s %-*s %-*s %s\n",
length, "start", length, "end", length, "size", "prot");
walk_memory_regions(f, dump_region);
}
int page_get_flags(target_ulong address)
{
PageDesc *p;
p = page_find(address >> TARGET_PAGE_BITS);
if (!p) {
return 0;
}
return p->flags;
}
/*
* Allow the target to decide if PAGE_TARGET_[12] may be reset.
* By default, they are not kept.
*/
#ifndef PAGE_TARGET_STICKY
#define PAGE_TARGET_STICKY 0
#endif
#define PAGE_STICKY (PAGE_ANON | PAGE_PASSTHROUGH | PAGE_TARGET_STICKY)
/*
* Modify the flags of a page and invalidate the code if necessary.
* The flag PAGE_WRITE_ORG is positioned automatically depending
* on PAGE_WRITE. The mmap_lock should already be held.
*/
void page_set_flags(target_ulong start, target_ulong end, int flags)
{
target_ulong addr, len;
bool reset, inval_tb = false;
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
a missing call to h2g_valid. */
assert(end - 1 <= GUEST_ADDR_MAX);
assert(start < end);
/* Only set PAGE_ANON with new mappings. */
assert(!(flags & PAGE_ANON) || (flags & PAGE_RESET));
assert_memory_lock();
start = start & TARGET_PAGE_MASK;
end = TARGET_PAGE_ALIGN(end);
if (flags & PAGE_WRITE) {
flags |= PAGE_WRITE_ORG;
}
reset = !(flags & PAGE_VALID) || (flags & PAGE_RESET);
if (reset) {
page_reset_target_data(start, end);
}
flags &= ~PAGE_RESET;
for (addr = start, len = end - start;
len != 0;
len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
PageDesc *p = page_find_alloc(addr >> TARGET_PAGE_BITS, true);
/*
* If the page was executable, but is reset, or is no longer
* executable, or has become writable, then invalidate any code.
*/
if ((p->flags & PAGE_EXEC)
&& (reset ||
!(flags & PAGE_EXEC) ||
(flags & ~p->flags & PAGE_WRITE))) {
inval_tb = true;
}
/* Using mprotect on a page does not change sticky bits. */
p->flags = (reset ? 0 : p->flags & PAGE_STICKY) | flags;
}
if (inval_tb) {
tb_invalidate_phys_range(start, end);
}
}
int page_check_range(target_ulong start, target_ulong len, int flags)
{
PageDesc *p;
target_ulong end;
target_ulong addr;
/*
* This function should never be called with addresses outside the
* guest address space. If this assert fires, it probably indicates
* a missing call to h2g_valid.
*/
if (TARGET_ABI_BITS > L1_MAP_ADDR_SPACE_BITS) {
assert(start < ((target_ulong)1 << L1_MAP_ADDR_SPACE_BITS));
}
if (len == 0) {
return 0;
}
if (start + len - 1 < start) {
/* We've wrapped around. */
return -1;
}
/* must do before we loose bits in the next step */
end = TARGET_PAGE_ALIGN(start + len);
start = start & TARGET_PAGE_MASK;
for (addr = start, len = end - start;
len != 0;
len -= TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
if (!p) {
return -1;
}
if (!(p->flags & PAGE_VALID)) {
return -1;
}
if ((flags & PAGE_READ) && !(p->flags & PAGE_READ)) {
return -1;
}
if (flags & PAGE_WRITE) {
if (!(p->flags & PAGE_WRITE_ORG)) {
return -1;
}
/* unprotect the page if it was put read-only because it
contains translated code */
if (!(p->flags & PAGE_WRITE)) {
if (!page_unprotect(addr, 0)) {
return -1;
}
}
}
}
return 0;
}
void page_protect(tb_page_addr_t page_addr)
{
target_ulong addr;
PageDesc *p;
int prot;
p = page_find(page_addr >> TARGET_PAGE_BITS);
if (p && (p->flags & PAGE_WRITE)) {
/*
* Force the host page as non writable (writes will have a page fault +
* mprotect overhead).
*/
page_addr &= qemu_host_page_mask;
prot = 0;
for (addr = page_addr; addr < page_addr + qemu_host_page_size;
addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
if (!p) {
continue;
}
prot |= p->flags;
p->flags &= ~PAGE_WRITE;
}
mprotect(g2h_untagged(page_addr), qemu_host_page_size,
(prot & PAGE_BITS) & ~PAGE_WRITE);
}
}
/*
* Called from signal handler: invalidate the code and unprotect the
* page. Return 0 if the fault was not handled, 1 if it was handled,
* and 2 if it was handled but the caller must cause the TB to be
* immediately exited. (We can only return 2 if the 'pc' argument is
* non-zero.)
*/
int page_unprotect(target_ulong address, uintptr_t pc)
{
unsigned int prot;
bool current_tb_invalidated;
PageDesc *p;
target_ulong host_start, host_end, addr;
/*
* Technically this isn't safe inside a signal handler. However we
* know this only ever happens in a synchronous SEGV handler, so in
* practice it seems to be ok.
*/
mmap_lock();
p = page_find(address >> TARGET_PAGE_BITS);
if (!p) {
mmap_unlock();
return 0;
}
/*
* If the page was really writable, then we change its
* protection back to writable.
*/
if (p->flags & PAGE_WRITE_ORG) {
current_tb_invalidated = false;
if (p->flags & PAGE_WRITE) {
/*
* If the page is actually marked WRITE then assume this is because
* this thread raced with another one which got here first and
* set the page to PAGE_WRITE and did the TB invalidate for us.
*/
#ifdef TARGET_HAS_PRECISE_SMC
TranslationBlock *current_tb = tcg_tb_lookup(pc);
if (current_tb) {
current_tb_invalidated = tb_cflags(current_tb) & CF_INVALID;
}
#endif
} else {
host_start = address & qemu_host_page_mask;
host_end = host_start + qemu_host_page_size;
prot = 0;
for (addr = host_start; addr < host_end; addr += TARGET_PAGE_SIZE) {
p = page_find(addr >> TARGET_PAGE_BITS);
p->flags |= PAGE_WRITE;
prot |= p->flags;
/*
* Since the content will be modified, we must invalidate
* the corresponding translated code.
*/
current_tb_invalidated |=
tb_invalidate_phys_page_unwind(addr, pc);
}
mprotect((void *)g2h_untagged(host_start), qemu_host_page_size,
prot & PAGE_BITS);
}
mmap_unlock();
/* If current TB was invalidated return to main loop */
return current_tb_invalidated ? 2 : 1;
}
mmap_unlock();
return 0;
}
static int probe_access_internal(CPUArchState *env, target_ulong addr,
int fault_size, MMUAccessType access_type,
bool nonfault, uintptr_t ra)