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linux-user: Move some mmap checks outside the lock

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Basic validation of operands does not require the lock.
Hoist them from target_mmap__locked back into target_mmap.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20240102015808.132373-18-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-01-02 12:57:52 +11:00
parent d558c395a9
commit e8cec51be0
1 changed files with 53 additions and 54 deletions
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107
linux-user/mmap.c
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@ -491,52 +491,14 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size, abi_ulong align)
} }
static abi_long target_mmap__locked(abi_ulong start, abi_ulong len, static abi_long target_mmap__locked(abi_ulong start, abi_ulong len,
int target_prot, int flags, int target_prot, int flags, int page_flags,
int fd, off_t offset) int fd, off_t offset)
{ {
int host_page_size = qemu_real_host_page_size(); int host_page_size = qemu_real_host_page_size();
abi_ulong ret, last, real_start, real_last, retaddr, host_len; abi_ulong ret, last, real_start, real_last, retaddr, host_len;
abi_ulong passthrough_start = -1, passthrough_last = 0; abi_ulong passthrough_start = -1, passthrough_last = 0;
int page_flags;
off_t host_offset; off_t host_offset;
if (!len) {
errno = EINVAL;
return -1;
}
page_flags = validate_prot_to_pageflags(target_prot);
if (!page_flags) {
errno = EINVAL;
return -1;
}
/* Also check for overflows... */
len = TARGET_PAGE_ALIGN(len);
if (!len) {
errno = ENOMEM;
return -1;
}
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
}
/*
* If we're mapping shared memory, ensure we generate code for parallel
* execution and flush old translations. This will work up to the level
* supported by the host -- anything that requires EXCP_ATOMIC will not
* be atomic with respect to an external process.
*/
if (flags & MAP_SHARED) {
CPUState *cpu = thread_cpu;
if (!(cpu->tcg_cflags & CF_PARALLEL)) {
cpu->tcg_cflags |= CF_PARALLEL;
tb_flush(cpu);
}
}
real_start = start & -host_page_size; real_start = start & -host_page_size;
host_offset = offset & -host_page_size; host_offset = offset & -host_page_size;
@ -616,23 +578,9 @@ static abi_long target_mmap__locked(abi_ulong start, abi_ulong len,
passthrough_start = start; passthrough_start = start;
passthrough_last = last; passthrough_last = last;
} else { } else {
if (start & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
}
last = start + len - 1; last = start + len - 1;
real_last = ROUND_UP(last, host_page_size) - 1; real_last = ROUND_UP(last, host_page_size) - 1;
/*
* Test if requested memory area fits target address space
* It can fail only on 64-bit host with 32-bit target.
* On any other target/host host mmap() handles this error correctly.
*/
if (last < start || !guest_range_valid_untagged(start, len)) {
errno = ENOMEM;
return -1;
}
if (flags & MAP_FIXED_NOREPLACE) { if (flags & MAP_FIXED_NOREPLACE) {
/* Validate that the chosen range is empty. */ /* Validate that the chosen range is empty. */
if (!page_check_range_empty(start, last)) { if (!page_check_range_empty(start, last)) {
@ -778,13 +726,64 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
int flags, int fd, off_t offset) int flags, int fd, off_t offset)
{ {
abi_long ret; abi_long ret;
int page_flags;
trace_target_mmap(start, len, target_prot, flags, fd, offset); trace_target_mmap(start, len, target_prot, flags, fd, offset);
if (!len) {
errno = EINVAL;
return -1;
}
page_flags = validate_prot_to_pageflags(target_prot);
if (!page_flags) {
errno = EINVAL;
return -1;
}
/* Also check for overflows... */
len = TARGET_PAGE_ALIGN(len);
if (!len || len != (size_t)len) {
errno = ENOMEM;
return -1;
}
if (offset & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
}
if (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE)) {
if (start & ~TARGET_PAGE_MASK) {
errno = EINVAL;
return -1;
}
if (!guest_range_valid_untagged(start, len)) {
errno = ENOMEM;
return -1;
}
}
mmap_lock(); mmap_lock();
ret = target_mmap__locked(start, len, target_prot, flags, fd, offset); ret = target_mmap__locked(start, len, target_prot, flags,
page_flags, fd, offset);
mmap_unlock(); mmap_unlock();
/*
* If we're mapping shared memory, ensure we generate code for parallel
* execution and flush old translations. This will work up to the level
* supported by the host -- anything that requires EXCP_ATOMIC will not
* be atomic with respect to an external process.
*/
if (ret != -1 && (flags & MAP_TYPE) != MAP_PRIVATE) {
CPUState *cpu = thread_cpu;
if (!(cpu->tcg_cflags & CF_PARALLEL)) {
cpu->tcg_cflags |= CF_PARALLEL;
tb_flush(cpu);
}
}
return ret; return ret;
} }