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[PATCH for-8.0 11/11] linux-user/arm: Take more care allocating commpage
From: |
Richard Henderson |
Subject: |
[PATCH for-8.0 11/11] linux-user/arm: Take more care allocating commpage |
Date: |
Wed, 22 Mar 2023 08:07:44 -0700 |
User setting of -R reserved_va can lead to an assertion
failure in page_set_flags. Sanity check the value of
reserved_va and print an error message instead. Do not
allocate a commpage at all for m-profile cpus.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/elfload.c | 37 +++++++++++++++++++++++++++----------
1 file changed, 27 insertions(+), 10 deletions(-)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index b068676340..0529430b1d 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -422,12 +422,32 @@ enum {
static bool init_guest_commpage(void)
{
- abi_ptr commpage = HI_COMMPAGE & -qemu_host_page_size;
- void *want = g2h_untagged(commpage);
- void *addr = mmap(want, qemu_host_page_size, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+ ARMCPU *cpu = ARM_CPU(thread_cpu);
+ abi_ptr want = HI_COMMPAGE & TARGET_PAGE_MASK;
+ abi_ptr addr;
- if (addr == MAP_FAILED) {
+ /*
+ * M-profile allocates maximum of 2GB address space, so can never
+ * allocate the commpage. Skip it.
+ */
+ if (arm_feature(&cpu->env, ARM_FEATURE_M)) {
+ return true;
+ }
+
+ /*
+ * If reserved_va does not cover the commpage, we get an assert
+ * in page_set_flags. Produce an intelligent error instead.
+ */
+ if (reserved_va != 0 && want + TARGET_PAGE_SIZE - 1 > reserved_va) {
+ error_report("Allocating guest commpage: -R 0x%" PRIx64 " too small",
+ (uint64_t)reserved_va + 1);
+ exit(EXIT_FAILURE);
+ }
+
+ addr = target_mmap(want, TARGET_PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
+
+ if (addr == -1) {
perror("Allocating guest commpage");
exit(EXIT_FAILURE);
}
@@ -436,15 +456,12 @@ static bool init_guest_commpage(void)
}
/* Set kernel helper versions; rest of page is 0. */
- __put_user(5, (uint32_t *)g2h_untagged(0xffff0ffcu));
+ put_user_u32(5, 0xffff0ffcu);
- if (mprotect(addr, qemu_host_page_size, PROT_READ)) {
+ if (target_mprotect(addr, qemu_host_page_size, PROT_READ | PROT_EXEC)) {
perror("Protecting guest commpage");
exit(EXIT_FAILURE);
}
-
- page_set_flags(commpage, commpage | ~qemu_host_page_mask,
- PAGE_READ | PAGE_EXEC | PAGE_VALID);
return true;
}
--
2.34.1
- [PATCH for-8.0 00/11] tcg patch queue, Richard Henderson, 2023/03/22
- [PATCH for-8.0 02/11] tcg: use QTree instead of GTree, Richard Henderson, 2023/03/22
- [PATCH for-8.0 03/11] linux-user: Diagnose misaligned -R size, Richard Henderson, 2023/03/22
- [PATCH for-8.0 01/11] util: import GTree as QTree, Richard Henderson, 2023/03/22
- [PATCH for-8.0 04/11] include/exec: Change reserved_va semantics to last byte, Richard Henderson, 2023/03/22
- [PATCH for-8.0 05/11] accel/tcg: Pass last not end to page_set_flags, Richard Henderson, 2023/03/22
- [PATCH for-8.0 07/11] accel/tcg: Pass last not end to PAGE_FOR_EACH_TB, Richard Henderson, 2023/03/22
- [PATCH for-8.0 11/11] linux-user/arm: Take more care allocating commpage,
Richard Henderson <=
- [PATCH for-8.0 10/11] accel/tcg: Pass last not end to tb_invalidate_phys_range, Richard Henderson, 2023/03/22
- [PATCH for-8.0 09/11] accel/tcg: Pass last not end to tb_invalidate_phys_page_range__locked, Richard Henderson, 2023/03/22
- [PATCH for-8.0 06/11] accel/tcg: Pass last not end to page_reset_target_data, Richard Henderson, 2023/03/22
- [PATCH for-8.0 08/11] accel/tcg: Pass last not end to page_collection_lock, Richard Henderson, 2023/03/22
- Re: [PATCH for-8.0 00/11] tcg patch queue, Richard Henderson, 2023/03/26