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[92.23.208.66]) by smtp.gmail.com with ESMTPSA id q10-20020a1ce90a000000b003fbb25da65bsm3337736wmc.30.2023.07.07.13.41.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Jul 2023 13:41:03 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: laurent@vivier.eu, mjt@tls.msk.ru, =?utf-8?q?Alex_Benn=C3=A9e?= Subject: [PATCH v2 10/24] linux-user: Split out target_to_host_prot Date: Fri, 7 Jul 2023 21:40:40 +0100 Message-Id: <20230707204054.8792-13-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230707204054.8792-1-richard.henderson@linaro.org> References: <20230707204054.8792-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::436; envelope-from=richard.henderson@linaro.org; helo=mail-wr1-x436.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Split out from validate_prot_to_pageflags, as there is not one single host_prot for the entire range. We need to adjust prot for every host page that overlaps multiple guest pages. Reviewed-by: Alex Bennée Signed-off-by: Richard Henderson --- linux-user/mmap.c | 77 +++++++++++++++++++++++++++-------------------- 1 file changed, 44 insertions(+), 33 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index b2e130e700..422583ed4f 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -68,24 +68,11 @@ void mmap_fork_end(int child) * Return 0 if the target prot bitmask is invalid, otherwise * the internal qemu page_flags (which will include PAGE_VALID). */ -static int validate_prot_to_pageflags(int *host_prot, int prot) +static int validate_prot_to_pageflags(int prot) { int valid = PROT_READ | PROT_WRITE | PROT_EXEC | TARGET_PROT_SEM; int page_flags = (prot & PAGE_BITS) | PAGE_VALID; - /* - * For the host, we need not pass anything except read/write/exec. - * While PROT_SEM is allowed by all hosts, it is also ignored, so - * don't bother transforming guest bit to host bit. Any other - * target-specific prot bits will not be understood by the host - * and will need to be encoded into page_flags for qemu emulation. - * - * Pages that are executable by the guest will never be executed - * by the host, but the host will need to be able to read them. - */ - *host_prot = (prot & (PROT_READ | PROT_WRITE)) - | (prot & PROT_EXEC ? PROT_READ : 0); - #ifdef TARGET_AARCH64 { ARMCPU *cpu = ARM_CPU(thread_cpu); @@ -113,18 +100,34 @@ static int validate_prot_to_pageflags(int *host_prot, int prot) return prot & ~valid ? 0 : page_flags; } +/* + * For the host, we need not pass anything except read/write/exec. + * While PROT_SEM is allowed by all hosts, it is also ignored, so + * don't bother transforming guest bit to host bit. Any other + * target-specific prot bits will not be understood by the host + * and will need to be encoded into page_flags for qemu emulation. + * + * Pages that are executable by the guest will never be executed + * by the host, but the host will need to be able to read them. + */ +static int target_to_host_prot(int prot) +{ + return (prot & (PROT_READ | PROT_WRITE)) | + (prot & PROT_EXEC ? PROT_READ : 0); +} + /* NOTE: all the constants are the HOST ones, but addresses are target. */ int target_mprotect(abi_ulong start, abi_ulong len, int target_prot) { abi_ulong end, host_start, host_end, addr; - int prot1, ret, page_flags, host_prot; + int prot1, ret, page_flags; trace_target_mprotect(start, len, target_prot); if ((start & ~TARGET_PAGE_MASK) != 0) { return -TARGET_EINVAL; } - page_flags = validate_prot_to_pageflags(&host_prot, target_prot); + page_flags = validate_prot_to_pageflags(target_prot); if (!page_flags) { return -TARGET_EINVAL; } @@ -142,7 +145,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int target_prot) host_end = HOST_PAGE_ALIGN(end); if (start > host_start) { /* handle host page containing start */ - prot1 = host_prot; + prot1 = target_prot; for (addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) { prot1 |= page_get_flags(addr); } @@ -153,19 +156,19 @@ int target_mprotect(abi_ulong start, abi_ulong len, int target_prot) end = host_end; } ret = mprotect(g2h_untagged(host_start), qemu_host_page_size, - prot1 & PAGE_BITS); + target_to_host_prot(prot1)); if (ret != 0) { goto error; } host_start += qemu_host_page_size; } if (end < host_end) { - prot1 = host_prot; + prot1 = target_prot; for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) { prot1 |= page_get_flags(addr); } ret = mprotect(g2h_untagged(host_end - qemu_host_page_size), - qemu_host_page_size, prot1 & PAGE_BITS); + qemu_host_page_size, target_to_host_prot(prot1)); if (ret != 0) { goto error; } @@ -174,8 +177,8 @@ int target_mprotect(abi_ulong start, abi_ulong len, int target_prot) /* handle the pages in the middle */ if (host_start < host_end) { - ret = mprotect(g2h_untagged(host_start), - host_end - host_start, host_prot); + ret = mprotect(g2h_untagged(host_start), host_end - host_start, + target_to_host_prot(target_prot)); if (ret != 0) { goto error; } @@ -211,7 +214,8 @@ static int mmap_frag(abi_ulong real_start, if (prot1 == 0) { /* no page was there, so we allocate one */ - void *p = mmap(host_start, qemu_host_page_size, prot, + void *p = mmap(host_start, qemu_host_page_size, + target_to_host_prot(prot), flags | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) { return -1; @@ -232,7 +236,8 @@ static int mmap_frag(abi_ulong real_start, /* adjust protection to be able to read */ if (!(prot1 & PROT_WRITE)) { - mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE); + mprotect(host_start, qemu_host_page_size, + target_to_host_prot(prot1) | PROT_WRITE); } /* read the corresponding file data */ @@ -242,11 +247,13 @@ static int mmap_frag(abi_ulong real_start, /* put final protection */ if (prot_new != (prot1 | PROT_WRITE)) { - mprotect(host_start, qemu_host_page_size, prot_new); + mprotect(host_start, qemu_host_page_size, + target_to_host_prot(prot_new)); } } else { if (prot_new != prot1) { - mprotect(host_start, qemu_host_page_size, prot_new); + mprotect(host_start, qemu_host_page_size, + target_to_host_prot(prot_new)); } if (prot_new & PROT_WRITE) { memset(g2h_untagged(start), 0, end - start); @@ -459,7 +466,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, { abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len, passthrough_start = -1, passthrough_end = -1; - int page_flags, host_prot; + int page_flags; mmap_lock(); trace_target_mmap(start, len, target_prot, flags, fd, offset); @@ -469,7 +476,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, goto fail; } - page_flags = validate_prot_to_pageflags(&host_prot, target_prot); + page_flags = validate_prot_to_pageflags(target_prot); if (!page_flags) { errno = EINVAL; goto fail; @@ -552,10 +559,12 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, if (!(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) { unsigned long host_start; + int host_prot; void *p; host_len = len + offset - host_offset; host_len = HOST_PAGE_ALIGN(host_len); + host_prot = target_to_host_prot(target_prot); /* * Note: we prefer to control the mapping address. It is @@ -612,6 +621,8 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, */ if (!(flags & MAP_ANONYMOUS) && (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) { + int host_prot = target_to_host_prot(target_prot); + /* * msync() won't work here, so we return an error if write is * possible while it is a shared mapping @@ -620,7 +631,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, errno = EINVAL; goto fail; } - retaddr = target_mmap(start, len, target_prot | PROT_WRITE, + retaddr = target_mmap(start, len, host_prot | PROT_WRITE, (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE)) | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); @@ -642,14 +653,14 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, if (real_end == real_start + qemu_host_page_size) { /* one single host page */ ret = mmap_frag(real_start, start, end, - host_prot, flags, fd, offset); + target_prot, flags, fd, offset); if (ret == -1) { goto fail; } goto the_end1; } ret = mmap_frag(real_start, start, real_start + qemu_host_page_size, - host_prot, flags, fd, offset); + target_prot, flags, fd, offset); if (ret == -1) { goto fail; } @@ -659,7 +670,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, if (end < real_end) { ret = mmap_frag(real_end - qemu_host_page_size, real_end - qemu_host_page_size, end, - host_prot, flags, fd, + target_prot, flags, fd, offset + real_end - qemu_host_page_size - start); if (ret == -1) { goto fail; @@ -677,7 +688,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot, offset1 = offset + real_start - start; } p = mmap(g2h_untagged(real_start), real_end - real_start, - host_prot, flags, fd, offset1); + target_to_host_prot(target_prot), flags, fd, offset1); if (p == MAP_FAILED) { goto fail; }