From patchwork Thu Jul 25 07:21:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chenyi Qiang X-Patchwork-Id: 13741599 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 2460BC3DA5D for ; Thu, 25 Jul 2024 07:23:22 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sWsoS-0006Bc-TJ; Thu, 25 Jul 2024 03:22:56 -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 1sWsoO-0005xx-Bw for qemu-devel@nongnu.org; Thu, 25 Jul 2024 03:22:52 -0400 Received: from mgamail.intel.com ([198.175.65.13]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sWsoL-0001KE-9w for qemu-devel@nongnu.org; Thu, 25 Jul 2024 03:22:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1721892169; x=1753428169; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=w97J4M33cCw9TAhSRTajDSuiBoryiegLBL0geGMjfTo=; b=Ogat1gvGyq1Isqz7MF1PNXi/5N/UiLDhN+5sdSiWk5XZs8DZOCkdbFor W+avTm3l0whH52wXQtXR13TB12QR3wvTLQBieSyqoVhar5wxzcCPg0IpX HfkNVjRMUUQFvs5Yzio1kQLqRxsItcsN7gnrRWxnjhy14xg2CD0tiFlP7 WFk57/bGWJMwty4w6CU/nhrmGIkw3j+7JS7jcl6bmPSnM4FValLLcdz/i 5JP9wrE4hEe9CPd2O/HFc6geAxyxLskMmImslgjZsecKAyzEvAXHVwnZh ch+2wucrAs1dOsWILU8loC8ehx2mPOBrumbFt4LErCA9SBz8HDCSAcbIE w==; X-CSE-ConnectionGUID: 4mPfPkaKR9quYbxzKMAAlg== X-CSE-MsgGUID: kmo65k4sQviT6ppGgW8aEw== X-IronPort-AV: E=McAfee;i="6700,10204,11143"; a="30753939" X-IronPort-AV: E=Sophos;i="6.09,235,1716274800"; d="scan'208";a="30753939" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jul 2024 00:22:46 -0700 X-CSE-ConnectionGUID: trBWNliyQSCF+mniCghpGg== X-CSE-MsgGUID: Cj11aMxMTk2JVZHfE+JW4g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,235,1716274800"; d="scan'208";a="52858154" Received: from emr-bkc.sh.intel.com ([10.112.230.82]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jul 2024 00:22:43 -0700 From: Chenyi Qiang To: Paolo Bonzini , David Hildenbrand , Peter Xu , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Michael Roth Cc: Chenyi Qiang , qemu-devel@nongnu.org, kvm@vger.kernel.org, Williams Dan J , Edgecombe Rick P , Wang Wei W , Peng Chao P , Gao Chao , Wu Hao , Xu Yilun Subject: [RFC PATCH 2/6] guest_memfd: Introduce a helper to notify the shared/private state change Date: Thu, 25 Jul 2024 03:21:11 -0400 Message-ID: <20240725072118.358923-3-chenyi.qiang@intel.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20240725072118.358923-1-chenyi.qiang@intel.com> References: <20240725072118.358923-1-chenyi.qiang@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=198.175.65.13; envelope-from=chenyi.qiang@intel.com; helo=mgamail.intel.com X-Spam_score_int: -44 X-Spam_score: -4.5 X-Spam_bar: ---- X-Spam_report: (-4.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.136, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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 Introduce a helper function within RamDiscardManager to efficiently notify all registered RamDiscardListeners, including VFIO listeners about the memory conversion events between shared and private in guest_memfd. The existing VFIO listener can dynamically DMA map/unmap the shared pages based on the conversion type: - For conversions from shared to private, the VFIO system ensures the discarding of shared mapping from the IOMMU. - For conversions from private to shared, it triggers the population of the shared mapping into the IOMMU. Additionally, there could be some special conversion requests: - When a conversion request is made for a page already in the desired state (either private or shared), the helper simply returns success. - For requests involving a range partially in the desired state, only the necessary segments are converted, ensuring the entire range complies with the request efficiently. - In scenarios where a conversion request is declined by other systems, such as a failure from VFIO during notify_populate(), the helper will roll back the request, maintaining consistency. Signed-off-by: Chenyi Qiang --- include/sysemu/guest-memfd-manager.h | 3 + system/guest-memfd-manager.c | 141 +++++++++++++++++++++++++++ 2 files changed, 144 insertions(+) diff --git a/include/sysemu/guest-memfd-manager.h b/include/sysemu/guest-memfd-manager.h index ab8c2ba362..1cce4cde43 100644 --- a/include/sysemu/guest-memfd-manager.h +++ b/include/sysemu/guest-memfd-manager.h @@ -43,4 +43,7 @@ struct GuestMemfdManagerClass { void (*realize)(Object *gmm, MemoryRegion *mr, uint64_t region_size); }; +int guest_memfd_state_change(GuestMemfdManager *gmm, uint64_t offset, uint64_t size, + bool shared_to_private); + #endif diff --git a/system/guest-memfd-manager.c b/system/guest-memfd-manager.c index 7b90f26859..deb43db90b 100644 --- a/system/guest-memfd-manager.c +++ b/system/guest-memfd-manager.c @@ -243,6 +243,147 @@ static void guest_memfd_rdm_replay_discarded(const RamDiscardManager *rdm, guest_memfd_rdm_replay_discarded_cb); } +static bool guest_memfd_is_valid_range(GuestMemfdManager *gmm, + uint64_t offset, uint64_t size) +{ + MemoryRegion *mr = gmm->mr; + + g_assert(mr); + + uint64_t region_size = memory_region_size(mr); + if (!QEMU_IS_ALIGNED(offset, gmm->block_size)) { + return false; + } + if (offset + size < offset || !size) { + return false; + } + if (offset >= region_size || offset + size > region_size) { + return false; + } + return true; +} + +static void guest_memfd_notify_discard(GuestMemfdManager *gmm, + uint64_t offset, uint64_t size) +{ + RamDiscardListener *rdl; + + QLIST_FOREACH(rdl, &gmm->rdl_list, next) { + MemoryRegionSection tmp = *rdl->section; + + if (!guest_memfd_rdm_intersect_memory_section(&tmp, offset, size)) { + continue; + } + + guest_memfd_for_each_populated_range(gmm, &tmp, rdl, + guest_memfd_notify_discard_cb); + } +} + + +static int guest_memfd_notify_populate(GuestMemfdManager *gmm, + uint64_t offset, uint64_t size) +{ + RamDiscardListener *rdl, *rdl2; + int ret = 0; + + QLIST_FOREACH(rdl, &gmm->rdl_list, next) { + MemoryRegionSection tmp = *rdl->section; + + if (!guest_memfd_rdm_intersect_memory_section(&tmp, offset, size)) { + continue; + } + + ret = guest_memfd_for_each_discarded_range(gmm, &tmp, rdl, + guest_memfd_notify_populate_cb); + if (ret) { + break; + } + } + + if (ret) { + /* Notify all already-notified listeners. */ + QLIST_FOREACH(rdl2, &gmm->rdl_list, next) { + MemoryRegionSection tmp = *rdl2->section; + + if (rdl2 == rdl) { + break; + } + if (!guest_memfd_rdm_intersect_memory_section(&tmp, offset, size)) { + continue; + } + + guest_memfd_for_each_discarded_range(gmm, &tmp, rdl2, + guest_memfd_notify_discard_cb); + } + } + return ret; +} + +static bool guest_memfd_is_range_populated(GuestMemfdManager *gmm, + uint64_t offset, uint64_t size) +{ + const unsigned long first_bit = offset / gmm->block_size; + const unsigned long last_bit = first_bit + (size / gmm->block_size) - 1; + unsigned long found_bit; + + /* We fake a shorter bitmap to avoid searching too far. */ + found_bit = find_next_bit(gmm->discard_bitmap, last_bit + 1, first_bit); + return found_bit > last_bit; +} + +static bool guest_memfd_is_range_discarded(GuestMemfdManager *gmm, + uint64_t offset, uint64_t size) +{ + const unsigned long first_bit = offset / gmm->block_size; + const unsigned long last_bit = first_bit + (size / gmm->block_size) - 1; + unsigned long found_bit; + + /* We fake a shorter bitmap to avoid searching too far. */ + found_bit = find_next_zero_bit(gmm->discard_bitmap, last_bit + 1, first_bit); + return found_bit > last_bit; +} + +int guest_memfd_state_change(GuestMemfdManager *gmm, uint64_t offset, uint64_t size, + bool shared_to_private) +{ + int ret = 0; + + if (!guest_memfd_is_valid_range(gmm, offset, size)) { + error_report("%s, invalid range: offset 0x%lx, size 0x%lx", + __func__, offset, size); + return -1; + } + + if ((shared_to_private && guest_memfd_is_range_discarded(gmm, offset, size)) || + (!shared_to_private && guest_memfd_is_range_populated(gmm, offset, size))) { + return 0; + } + + if (shared_to_private) { + guest_memfd_notify_discard(gmm, offset, size); + } else { + ret = guest_memfd_notify_populate(gmm, offset, size); + } + + if (!ret) { + unsigned long first_bit = offset / gmm->block_size; + unsigned long nbits = size / gmm->block_size; + + g_assert((first_bit + nbits) <= gmm->discard_bitmap_size); + + if (shared_to_private) { + bitmap_set(gmm->discard_bitmap, first_bit, nbits); + } else { + bitmap_clear(gmm->discard_bitmap, first_bit, nbits); + } + + return 0; + } + + return ret; +} + static void guest_memfd_manager_realize(Object *obj, MemoryRegion *mr, uint64_t region_size) {