From patchwork Thu Sep 14 03:51:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoyao Li X-Patchwork-Id: 13384378 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 20CE6CA0ECE for ; Thu, 14 Sep 2023 03:53:45 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qgdPJ-000837-0B; Wed, 13 Sep 2023 23:52:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgdP9-0007dp-2d for qemu-devel@nongnu.org; Wed, 13 Sep 2023 23:52:36 -0400 Received: from mgamail.intel.com ([134.134.136.24]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qgdP6-0000r7-Ko for qemu-devel@nongnu.org; Wed, 13 Sep 2023 23:52:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694663552; x=1726199552; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=P7JD5Z/Zea9/ImjYPBZjZe+vU1JZG61vgXwgTLUb5Js=; b=g2D/R85zhhIMkPTEeRC7h9Sdl+FtU6IeP6v2fK0yrDR3iyDOCBis5w7Z zDX0npoIcP/0MqlxaTZfw99EBuS2cTE5RAFHgO6qpIA5+Gh78vDnVDFIF 0eON0ClbcPUSPBiyLj4NuNIS+rXZ/jZ7rZpNkkdIH9VVHspZ1TdSDWl34 ydeB+mpNLNpIrJHxnIVXL7f3IH7qeRbtz4oA04U5fQC7j7yZS08LBdKuO hhwvolvCSqK+IrUq+WMUqhUsDR/IgpO/kpks7zhUN2kMkaK+v2hzdhmly epP8FkwpqgBKZRG1GBuoiPgEldXgd9fAp/Lzjc3RCv6HIU2dBtTYQFwAz A==; X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="381528503" X-IronPort-AV: E=Sophos;i="6.02,144,1688454000"; d="scan'208";a="381528503" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Sep 2023 20:52:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="814500659" X-IronPort-AV: E=Sophos;i="6.02,144,1688454000"; d="scan'208";a="814500659" Received: from lxy-clx-4s.sh.intel.com ([10.239.48.52]) by fmsmga004.fm.intel.com with ESMTP; 13 Sep 2023 20:52:27 -0700 From: Xiaoyao Li To: Paolo Bonzini , David Hildenbrand , Igor Mammedov , "Michael S. Tsirkin" , Marcel Apfelbaum , Richard Henderson , Peter Xu , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Cornelia Huck , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Eric Blake , Markus Armbruster , Marcelo Tosatti Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, xiaoyao.li@intel.com, Michael Roth , isaku.yamahata@gmail.com, Sean Christopherson , Claudio Fontana Subject: [RFC PATCH v2 15/21] physmem: extract ram_block_discard_range_fd() from ram_block_discard_range() Date: Wed, 13 Sep 2023 23:51:11 -0400 Message-Id: <20230914035117.3285885-16-xiaoyao.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230914035117.3285885-1-xiaoyao.li@intel.com> References: <20230914035117.3285885-1-xiaoyao.li@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=134.134.136.24; envelope-from=xiaoyao.li@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Extract the alignment check and sanity check out from ram_block_discard_range() into a seperate function ram_block_discard_range_fd(), which can be passed with an explicit fd as input parameter. ram_block_discard_range_fd() can be used to discard private memory range from gmem fd with later patch. When doing private memory <-> shared memory conversion, it requires 4KB alignment instead of RamBlock.page_size. Signed-off-by: Xiaoyao Li --- softmmu/physmem.c | 192 ++++++++++++++++++++++++---------------------- 1 file changed, 100 insertions(+), 92 deletions(-) diff --git a/softmmu/physmem.c b/softmmu/physmem.c index 34d580ec0d39..6ee6bc794f44 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -3425,117 +3425,125 @@ int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque) return ret; } +static int ram_block_discard_range_fd(RAMBlock *rb, uint64_t start, + size_t length, int fd) +{ + uint8_t *host_startaddr = rb->host + start; + bool need_madvise, need_fallocate; + int ret = -1; + + errno = ENOTSUP; /* If we are missing MADVISE etc */ + + /* The logic here is messy; + * madvise DONTNEED fails for hugepages + * fallocate works on hugepages and shmem + * shared anonymous memory requires madvise REMOVE + */ + need_madvise = (rb->page_size == qemu_host_page_size) && (rb->fd == fd); + need_fallocate = fd != -1; + + if (need_fallocate) { + /* For a file, this causes the area of the file to be zero'd + * if read, and for hugetlbfs also causes it to be unmapped + * so a userfault will trigger. + */ +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE + /* + * We'll discard data from the actual file, even though we only + * have a MAP_PRIVATE mapping, possibly messing with other + * MAP_PRIVATE/MAP_SHARED mappings. There is no easy way to + * change that behavior whithout violating the promised + * semantics of ram_block_discard_range(). + * + * Only warn, because it works as long as nobody else uses that + * file. + */ + if (!qemu_ram_is_shared(rb)) { + warn_report_once("%s: Discarding RAM" + " in private file mappings is possibly" + " dangerous, because it will modify the" + " underlying file and will affect other" + " users of the file", __func__); + } + + ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, + start, length); + if (ret) { + ret = -errno; + error_report("%s: Failed to fallocate %s:%" PRIx64 " +%zx (%d)", + __func__, rb->idstr, start, length, ret); + return ret; + } +#else + ret = -ENOSYS; + error_report("%s: fallocate not available/file " + "%s:%" PRIx64 " +%zx (%d)", + __func__, rb->idstr, start, length, ret); + return ret; +#endif + } + + if (need_madvise) { + /* For normal RAM this causes it to be unmapped, + * for shared memory it causes the local mapping to disappear + * and to fall back on the file contents (which we just + * fallocate'd away). + */ +#if defined(CONFIG_MADVISE) + if (qemu_ram_is_shared(rb) && fd < 0) { + ret = madvise(host_startaddr, length, QEMU_MADV_REMOVE); + } else { + ret = madvise(host_startaddr, length, QEMU_MADV_DONTNEED); + } + if (ret) { + ret = -errno; + error_report("%s: Failed to discard range %s:%" PRIx64 " +%zx (%d)", + __func__, rb->idstr, start, length, ret); + return ret; + } +#else + ret = -ENOSYS; + error_report("%s: MADVISE not available %s:%" PRIx64 " +%zx (%d)", + __func__, rb->idstr, start, length, ret); + return ret; +#endif + } + + trace_ram_block_discard_range(rb->idstr, host_startaddr, length, + need_madvise, need_fallocate, ret); + return ret; +} + /* * Unmap pages of memory from start to start+length such that * they a) read as 0, b) Trigger whatever fault mechanism * the OS provides for postcopy. + * * The pages must be unmapped by the end of the function. - * Returns: 0 on success, none-0 on failure - * + * Returns: 0 on success, none-0 on failure. */ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length) { - int ret = -1; - uint8_t *host_startaddr = rb->host + start; if (!QEMU_PTR_IS_ALIGNED(host_startaddr, rb->page_size)) { error_report("%s: Unaligned start address: %p", __func__, host_startaddr); - goto err; + return -1; } - if ((start + length) <= rb->max_length) { - bool need_madvise, need_fallocate; - if (!QEMU_IS_ALIGNED(length, rb->page_size)) { - error_report("%s: Unaligned length: %zx", __func__, length); - goto err; - } - - errno = ENOTSUP; /* If we are missing MADVISE etc */ - - /* The logic here is messy; - * madvise DONTNEED fails for hugepages - * fallocate works on hugepages and shmem - * shared anonymous memory requires madvise REMOVE - */ - need_madvise = (rb->page_size == qemu_host_page_size); - need_fallocate = rb->fd != -1; - if (need_fallocate) { - /* For a file, this causes the area of the file to be zero'd - * if read, and for hugetlbfs also causes it to be unmapped - * so a userfault will trigger. - */ -#ifdef CONFIG_FALLOCATE_PUNCH_HOLE - /* - * We'll discard data from the actual file, even though we only - * have a MAP_PRIVATE mapping, possibly messing with other - * MAP_PRIVATE/MAP_SHARED mappings. There is no easy way to - * change that behavior whithout violating the promised - * semantics of ram_block_discard_range(). - * - * Only warn, because it works as long as nobody else uses that - * file. - */ - if (!qemu_ram_is_shared(rb)) { - warn_report_once("%s: Discarding RAM" - " in private file mappings is possibly" - " dangerous, because it will modify the" - " underlying file and will affect other" - " users of the file", __func__); - } - - ret = fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, - start, length); - if (ret) { - ret = -errno; - error_report("%s: Failed to fallocate %s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); - goto err; - } -#else - ret = -ENOSYS; - error_report("%s: fallocate not available/file" - "%s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); - goto err; -#endif - } - if (need_madvise) { - /* For normal RAM this causes it to be unmapped, - * for shared memory it causes the local mapping to disappear - * and to fall back on the file contents (which we just - * fallocate'd away). - */ -#if defined(CONFIG_MADVISE) - if (qemu_ram_is_shared(rb) && rb->fd < 0) { - ret = madvise(host_startaddr, length, QEMU_MADV_REMOVE); - } else { - ret = madvise(host_startaddr, length, QEMU_MADV_DONTNEED); - } - if (ret) { - ret = -errno; - error_report("%s: Failed to discard range " - "%s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); - goto err; - } -#else - ret = -ENOSYS; - error_report("%s: MADVISE not available %s:%" PRIx64 " +%zx (%d)", - __func__, rb->idstr, start, length, ret); - goto err; -#endif - } - trace_ram_block_discard_range(rb->idstr, host_startaddr, length, - need_madvise, need_fallocate, ret); - } else { + if ((start + length) > rb->max_length) { error_report("%s: Overrun block '%s' (%" PRIu64 "/%zx/" RAM_ADDR_FMT")", __func__, rb->idstr, start, length, rb->max_length); + return -1; } -err: - return ret; + if (!QEMU_IS_ALIGNED(length, rb->page_size)) { + error_report("%s: Unaligned length: %zx", __func__, length); + return -1; + } + + return ram_block_discard_range_fd(rb, start, length, rb->fd); } bool ramblock_is_pmem(RAMBlock *rb)