From mboxrd@z Thu Jan 1 00:00:00 1970 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 21EFBC71148 for ; Thu, 12 Jun 2025 08:29:39 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uPdIJ-00081O-Om; Thu, 12 Jun 2025 04:28:19 -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 1uPdII-0007z7-Gh for qemu-devel@nongnu.org; Thu, 12 Jun 2025 04:28:18 -0400 Received: from mgamail.intel.com ([192.198.163.8]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uPdIC-0004Fi-Nd for qemu-devel@nongnu.org; Thu, 12 Jun 2025 04:28:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1749716893; x=1781252893; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LdiTvLQwV3NPajQBdRm+xuKF+dxYwpbIICIDW52TqYs=; b=ibxv7ARYeGBsicvoc41J4M06iwQttvDWUaCRvNn8o+uGTOnPx/LVAaNp dDrgZS0ILUHj284NcjIGS5doHKYDa6h07r0HCRqFjp5nqsNERhHhYADma gOmU8nDr0MOrVIQEFQPoJVhgw4hEHSwsjSykdklE89vRahTTd2iTtoytg Kek3sHOAVRcp2KOWrLLYHO2ma5coKxKjOCKWSyrXuNllZUy6TakB2r16z DtFFR5YsZul78ERGSR872GJKEILx9aL/Mm3zOoaDirVHau1lNg+M3TS0w BptpTPBy/a5WEeG1hyOpyik2MAClMx0Fs3t7PZPc+Z0RNsrIKBP3WDgXH Q==; X-CSE-ConnectionGUID: wtpApKrPTXa6ST4VxiW6PA== X-CSE-MsgGUID: hZ5NNS6vT3Cq4hg8amcoYw== X-IronPort-AV: E=McAfee;i="6800,10657,11461"; a="69453430" X-IronPort-AV: E=Sophos;i="6.16,230,1744095600"; d="scan'208";a="69453430" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2025 01:28:05 -0700 X-CSE-ConnectionGUID: pfpPH5VHSyCMjItiH4/4Fw== X-CSE-MsgGUID: I3o9yiCnSuuA9zi7OiOy+g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,230,1744095600"; d="scan'208";a="152442030" Received: from emr-bkc.sh.intel.com ([10.112.230.82]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jun 2025 01:28:01 -0700 From: Chenyi Qiang To: David Hildenbrand , Alexey Kardashevskiy , Peter Xu , Gupta Pankaj , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Michael Roth Cc: Chenyi Qiang , qemu-devel@nongnu.org, kvm@vger.kernel.org, Williams Dan J , Zhao Liu , Baolu Lu , Gao Chao , Xu Yilun , Li Xiaoyao , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Alex Williamson Subject: [PATCH v7 2/5] memory: Change memory_region_set_ram_discard_manager() to return the result Date: Thu, 12 Jun 2025 16:27:43 +0800 Message-ID: <20250612082747.51539-3-chenyi.qiang@intel.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250612082747.51539-1-chenyi.qiang@intel.com> References: <20250612082747.51539-1-chenyi.qiang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=192.198.163.8; envelope-from=chenyi.qiang@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, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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 Modify memory_region_set_ram_discard_manager() to return -EBUSY if a RamDiscardManager is already set in the MemoryRegion. The caller must handle this failure, such as having virtio-mem undo its actions and fail the realize() process. Opportunistically move the call earlier to avoid complex error handling. This change is beneficial when introducing a new RamDiscardManager instance besides virtio-mem. After ram_block_coordinated_discard_require(true) unlocks all RamDiscardManager instances, only one instance is allowed to be set for one MemoryRegion at present. Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Pankaj Gupta Tested-by: Alexey Kardashevskiy Reviewed-by: Alexey Kardashevskiy Reviewed-by: Xiaoyao Li Signed-off-by: Chenyi Qiang --- Changes in v7: - Add Reviewed-by from Pankaj, Alexey and Xiaoyao Changes in v6: - Add Reviewed-by from David. Changes in v5: - Nit in commit message (return false -> -EBUSY) - Add set_ram_discard_manager(NULL) when ram_block_discard_range() fails. Changes in v3: - Move set_ram_discard_manager() up to avoid a g_free() - Clean up set_ram_discard_manager() definition --- hw/virtio/virtio-mem.c | 30 +++++++++++++++++------------- include/system/memory.h | 6 +++--- system/memory.c | 10 +++++++--- 3 files changed, 27 insertions(+), 19 deletions(-) diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c index b3c126ea1e..2e491e8c44 100644 --- a/hw/virtio/virtio-mem.c +++ b/hw/virtio/virtio-mem.c @@ -1047,6 +1047,17 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) return; } + /* + * Set ourselves as RamDiscardManager before the plug handler maps the + * memory region and exposes it via an address space. + */ + if (memory_region_set_ram_discard_manager(&vmem->memdev->mr, + RAM_DISCARD_MANAGER(vmem))) { + error_setg(errp, "Failed to set RamDiscardManager"); + ram_block_coordinated_discard_require(false); + return; + } + /* * We don't know at this point whether shared RAM is migrated using * QEMU or migrated using the file content. "x-ignore-shared" will be @@ -1061,6 +1072,7 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb)); if (ret) { error_setg_errno(errp, -ret, "Unexpected error discarding RAM"); + memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL); ram_block_coordinated_discard_require(false); return; } @@ -1122,13 +1134,6 @@ static void virtio_mem_device_realize(DeviceState *dev, Error **errp) vmem->system_reset = VIRTIO_MEM_SYSTEM_RESET(obj); vmem->system_reset->vmem = vmem; qemu_register_resettable(obj); - - /* - * Set ourselves as RamDiscardManager before the plug handler maps the - * memory region and exposes it via an address space. - */ - memory_region_set_ram_discard_manager(&vmem->memdev->mr, - RAM_DISCARD_MANAGER(vmem)); } static void virtio_mem_device_unrealize(DeviceState *dev) @@ -1136,12 +1141,6 @@ static void virtio_mem_device_unrealize(DeviceState *dev) VirtIODevice *vdev = VIRTIO_DEVICE(dev); VirtIOMEM *vmem = VIRTIO_MEM(dev); - /* - * The unplug handler unmapped the memory region, it cannot be - * found via an address space anymore. Unset ourselves. - */ - memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL); - qemu_unregister_resettable(OBJECT(vmem->system_reset)); object_unref(OBJECT(vmem->system_reset)); @@ -1154,6 +1153,11 @@ static void virtio_mem_device_unrealize(DeviceState *dev) virtio_del_queue(vdev, 0); virtio_cleanup(vdev); g_free(vmem->bitmap); + /* + * The unplug handler unmapped the memory region, it cannot be + * found via an address space anymore. Unset ourselves. + */ + memory_region_set_ram_discard_manager(&vmem->memdev->mr, NULL); ram_block_coordinated_discard_require(false); } diff --git a/include/system/memory.h b/include/system/memory.h index da97753e28..60983d4977 100644 --- a/include/system/memory.h +++ b/include/system/memory.h @@ -2499,13 +2499,13 @@ static inline bool memory_region_has_ram_discard_manager(MemoryRegion *mr) * * This function must not be called for a mapped #MemoryRegion, a #MemoryRegion * that does not cover RAM, or a #MemoryRegion that already has a - * #RamDiscardManager assigned. + * #RamDiscardManager assigned. Return 0 if the rdm is set successfully. * * @mr: the #MemoryRegion * @rdm: #RamDiscardManager to set */ -void memory_region_set_ram_discard_manager(MemoryRegion *mr, - RamDiscardManager *rdm); +int memory_region_set_ram_discard_manager(MemoryRegion *mr, + RamDiscardManager *rdm); /** * memory_region_find: translate an address/size relative to a diff --git a/system/memory.c b/system/memory.c index 306e9ff9eb..d0c186e9f6 100644 --- a/system/memory.c +++ b/system/memory.c @@ -2106,12 +2106,16 @@ RamDiscardManager *memory_region_get_ram_discard_manager(MemoryRegion *mr) return mr->rdm; } -void memory_region_set_ram_discard_manager(MemoryRegion *mr, - RamDiscardManager *rdm) +int memory_region_set_ram_discard_manager(MemoryRegion *mr, + RamDiscardManager *rdm) { g_assert(memory_region_is_ram(mr)); - g_assert(!rdm || !mr->rdm); + if (mr->rdm && rdm) { + return -EBUSY; + } + mr->rdm = rdm; + return 0; } uint64_t ram_discard_manager_get_min_granularity(const RamDiscardManager *rdm, -- 2.43.5