diff options
Diffstat (limited to 'meta/recipes-devtools/qemu/qemu/0004-linux-user-Rewrite-target_shmat.patch')
| -rw-r--r-- | meta/recipes-devtools/qemu/qemu/0004-linux-user-Rewrite-target_shmat.patch | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/meta/recipes-devtools/qemu/qemu/0004-linux-user-Rewrite-target_shmat.patch b/meta/recipes-devtools/qemu/qemu/0004-linux-user-Rewrite-target_shmat.patch new file mode 100644 index 0000000000..88c3ed40b0 --- /dev/null +++ b/meta/recipes-devtools/qemu/qemu/0004-linux-user-Rewrite-target_shmat.patch @@ -0,0 +1,236 @@ +From cb48d5d1592e63ebd0d4a3e300ef98e38e6306d7 Mon Sep 17 00:00:00 2001 +From: Richard Henderson <richard.henderson@linaro.org> +Date: Wed, 28 Feb 2024 10:25:17 -1000 +Subject: [PATCH 4/5] linux-user: Rewrite target_shmat + +Handle combined host and guest alignment requirements. +Handle host and guest page size differences. +Handle SHM_EXEC. + +Upstream-Status: Submitted [https://www.mail-archive.com/qemu-devel@nongnu.org/msg1026793.html] + +Resolves: https://gitlab.com/qemu-project/qemu/-/issues/115 +Signed-off-by: Richard Henderson <richard.henderson@linaro.org> +Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org> +--- + linux-user/mmap.c | 166 +++++++++++++++++++++++++++++++++++++--------- + 1 file changed, 133 insertions(+), 33 deletions(-) + +diff --git a/linux-user/mmap.c b/linux-user/mmap.c +index 18fb3aaf7..6a2f649bb 100644 +--- a/linux-user/mmap.c ++++ b/linux-user/mmap.c +@@ -1062,69 +1062,161 @@ static inline abi_ulong target_shmlba(CPUArchState *cpu_env) + } + #endif + ++#if defined(__arm__) || defined(__mips__) || defined(__sparc__) ++#define HOST_FORCE_SHMLBA 1 ++#else ++#define HOST_FORCE_SHMLBA 0 ++#endif ++ + abi_ulong target_shmat(CPUArchState *cpu_env, int shmid, + abi_ulong shmaddr, int shmflg) + { + CPUState *cpu = env_cpu(cpu_env); +- abi_ulong raddr; + struct shmid_ds shm_info; + int ret; +- abi_ulong shmlba; ++ int h_pagesize; ++ int t_shmlba, h_shmlba, m_shmlba; ++ size_t t_len, h_len, m_len; + + /* shmat pointers are always untagged */ + +- /* find out the length of the shared memory segment */ ++ /* ++ * Because we can't use host shmat() unless the address is sufficiently ++ * aligned for the host, we'll need to check both. ++ * TODO: Could be fixed with softmmu. ++ */ ++ t_shmlba = target_shmlba(cpu_env); ++ h_pagesize = qemu_real_host_page_size(); ++ h_shmlba = (HOST_FORCE_SHMLBA ? SHMLBA : h_pagesize); ++ m_shmlba = MAX(t_shmlba, h_shmlba); ++ ++ if (shmaddr) { ++ if (shmaddr & (m_shmlba - 1)) { ++ if (shmflg & SHM_RND) { ++ /* ++ * The guest is allowing the kernel to round the address. ++ * Assume that the guest is ok with us rounding to the ++ * host required alignment too. Anyway if we don't, we'll ++ * get an error from the kernel. ++ */ ++ shmaddr &= ~(m_shmlba - 1); ++ if (shmaddr == 0 && (shmflg & SHM_REMAP)) { ++ return -TARGET_EINVAL; ++ } ++ } else { ++ int require = TARGET_PAGE_SIZE; ++#ifdef TARGET_FORCE_SHMLBA ++ require = t_shmlba; ++#endif ++ /* ++ * Include host required alignment, as otherwise we cannot ++ * use host shmat at all. ++ */ ++ require = MAX(require, h_shmlba); ++ if (shmaddr & (require - 1)) { ++ return -TARGET_EINVAL; ++ } ++ } ++ } ++ } else { ++ if (shmflg & SHM_REMAP) { ++ return -TARGET_EINVAL; ++ } ++ } ++ /* All rounding now manually concluded. */ ++ shmflg &= ~SHM_RND; ++ ++ /* Find out the length of the shared memory segment. */ + ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info)); + if (is_error(ret)) { + /* can't get length, bail out */ + return ret; + } ++ t_len = TARGET_PAGE_ALIGN(shm_info.shm_segsz); ++ h_len = ROUND_UP(shm_info.shm_segsz, h_pagesize); ++ m_len = MAX(t_len, h_len); + +- shmlba = target_shmlba(cpu_env); +- +- if (shmaddr & (shmlba - 1)) { +- if (shmflg & SHM_RND) { +- shmaddr &= ~(shmlba - 1); +- } else { +- return -TARGET_EINVAL; +- } +- } +- if (!guest_range_valid_untagged(shmaddr, shm_info.shm_segsz)) { ++ if (!guest_range_valid_untagged(shmaddr, m_len)) { + return -TARGET_EINVAL; + } + + WITH_MMAP_LOCK_GUARD() { +- void *host_raddr; ++ bool mapped = false; ++ void *want, *test; + abi_ulong last; + +- if (shmaddr) { +- host_raddr = shmat(shmid, (void *)g2h_untagged(shmaddr), shmflg); ++ if (!shmaddr) { ++ shmaddr = mmap_find_vma(0, m_len, m_shmlba); ++ if (shmaddr == -1) { ++ return -TARGET_ENOMEM; ++ } ++ mapped = !reserved_va; ++ } else if (shmflg & SHM_REMAP) { ++ /* ++ * If host page size > target page size, the host shmat may map ++ * more memory than the guest expects. Reject a mapping that ++ * would replace memory in the unexpected gap. ++ * TODO: Could be fixed with softmmu. ++ */ ++ if (t_len < h_len && ++ !page_check_range_empty(shmaddr + t_len, ++ shmaddr + h_len - 1)) { ++ return -TARGET_EINVAL; ++ } + } else { +- abi_ulong mmap_start; ++ if (!page_check_range_empty(shmaddr, shmaddr + m_len - 1)) { ++ return -TARGET_EINVAL; ++ } ++ } + +- /* In order to use the host shmat, we need to honor host SHMLBA. */ +- mmap_start = mmap_find_vma(0, shm_info.shm_segsz, +- MAX(SHMLBA, shmlba)); ++ /* All placement is now complete. */ ++ want = (void *)g2h_untagged(shmaddr); + +- if (mmap_start == -1) { +- return -TARGET_ENOMEM; ++ /* ++ * Map anonymous pages across the entire range, then remap with ++ * the shared memory. This is required for a number of corner ++ * cases for which host and guest page sizes differ. ++ */ ++ if (h_len != t_len) { ++ int mmap_p = PROT_READ | (shmflg & SHM_RDONLY ? 0 : PROT_WRITE); ++ int mmap_f = MAP_PRIVATE | MAP_ANONYMOUS ++ | (reserved_va || (shmflg & SHM_REMAP) ++ ? MAP_FIXED : MAP_FIXED_NOREPLACE); ++ ++ test = mmap(want, m_len, mmap_p, mmap_f, -1, 0); ++ if (unlikely(test != want)) { ++ /* shmat returns EINVAL not EEXIST like mmap. */ ++ ret = (test == MAP_FAILED && errno != EEXIST ++ ? get_errno(-1) : -TARGET_EINVAL); ++ if (mapped) { ++ do_munmap(want, m_len); ++ } ++ return ret; + } +- host_raddr = shmat(shmid, g2h_untagged(mmap_start), +- shmflg | SHM_REMAP); ++ mapped = true; + } + +- if (host_raddr == (void *)-1) { +- return get_errno(-1); ++ if (reserved_va || mapped) { ++ shmflg |= SHM_REMAP; ++ } ++ test = shmat(shmid, want, shmflg); ++ if (test == MAP_FAILED) { ++ ret = get_errno(-1); ++ if (mapped) { ++ do_munmap(want, m_len); ++ } ++ return ret; + } +- raddr = h2g(host_raddr); +- last = raddr + shm_info.shm_segsz - 1; ++ assert(test == want); + +- page_set_flags(raddr, last, ++ last = shmaddr + m_len - 1; ++ page_set_flags(shmaddr, last, + PAGE_VALID | PAGE_RESET | PAGE_READ | +- (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE)); ++ (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE) | ++ (shmflg & SHM_EXEC ? PAGE_EXEC : 0)); + +- shm_region_rm_complete(raddr, last); +- shm_region_add(raddr, last); ++ shm_region_rm_complete(shmaddr, last); ++ shm_region_add(shmaddr, last); + } + + /* +@@ -1138,7 +1230,15 @@ abi_ulong target_shmat(CPUArchState *cpu_env, int shmid, + tb_flush(cpu); + } + +- return raddr; ++ if (qemu_loglevel_mask(CPU_LOG_PAGE)) { ++ FILE *f = qemu_log_trylock(); ++ if (f) { ++ fprintf(f, "page layout changed following shmat\n"); ++ page_dump(f); ++ qemu_log_unlock(f); ++ } ++ } ++ return shmaddr; + } + + abi_long target_shmdt(abi_ulong shmaddr) +-- +2.34.1 + |