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linux-user: Remove can_passthrough_madvise 

Use page_check_range instead, which uses the interval tree
instead of checking each page individually.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230707204054.8792-26-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-07-07 21:40:53 +01:00
parent bef6f008b9
commit ecb796db03
1 changed files with 3 additions and 21 deletions
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24
linux-user/mmap.c
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@ -898,23 +898,6 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
return new_addr;
}
static bool can_passthrough_madvise(abi_ulong start, abi_ulong end)
{
ulong addr;
if ((start | end) & ~qemu_host_page_mask) {
return false;
}
for (addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
if (!(page_get_flags(addr) & PAGE_PASSTHROUGH)) {
return false;
}
}
return true;
}
abi_long target_madvise(abi_ulong start, abi_ulong len_in, int advice)
{
abi_ulong len, end;
@ -964,9 +947,8 @@ abi_long target_madvise(abi_ulong start, abi_ulong len_in, int advice)
*
* A straight passthrough for those may not be safe because qemu sometimes
* turns private file-backed mappings into anonymous mappings.
* can_passthrough_madvise() helps to check if a passthrough is possible by
* comparing mappings that are known to have the same semantics in the host
* and the guest. In this case passthrough is safe.
* If all guest pages have PAGE_PASSTHROUGH set, mappings have the
* same semantics for the host as for the guest.
*
* We pass through MADV_WIPEONFORK and MADV_KEEPONFORK if possible and
* return failure if not.
@ -984,7 +966,7 @@ abi_long target_madvise(abi_ulong start, abi_ulong len_in, int advice)
ret = -EINVAL;
/* fall through */
case MADV_DONTNEED:
if (can_passthrough_madvise(start, end)) {
if (page_check_range(start, len, PAGE_PASSTHROUGH)) {
ret = get_errno(madvise(g2h_untagged(start), len, advice));
if ((advice == MADV_DONTNEED) && (ret == 0)) {
page_reset_target_data(start, start + len - 1);