From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6926E272E4C for ; Tue, 20 May 2025 10:29:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747736954; cv=none; b=Kr1lM7q1RYTEQ/2T6Zz3aOrERPfMAbG52jwHKodN/ZE7eTBp4BGZUx/B0cfCLxyhDvSXVDNIO/tgcMutKYd7fojYiNDeOLTVl63CXJP+JB9sGpLNJmQeo1AJsEgBrGVwGaGLq180lJZtn4t7oQtD9PC6P056ntqLMzWfIY1Bzms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747736954; c=relaxed/simple; bh=R5LFT5AsG3wsPZY3KRrUkPR61WLL1e67GZCvt4H8Tkk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JHaqbNbhKu3mujs/OC+Koirv72H04khoCIhy4p9b6pHCULPnlO+gEoHg8W5XarLxmbcmyutx1R2IrRWXjuOV9eUGugjTz4UROgykty7Myc26QjOspIhMHurVU/G2s3dv2soS3pzRdCaoCq+WrD936J0WHWssBILzTzawnqBmDcA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=YIU1iz7u; arc=none smtp.client-ip=198.175.65.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="YIU1iz7u" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1747736952; x=1779272952; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=R5LFT5AsG3wsPZY3KRrUkPR61WLL1e67GZCvt4H8Tkk=; b=YIU1iz7uTooOZ3Ou9dU/sKL0s2RZAcW9YeNpF7aFYFltf87OZAXyEdw4 WXqHBM1JFKrgNSatvfpou8FMFR46eBXThen/MlRiFnuU0S4k2YW5chBCI mEy0rbnCi/zoUbdcDG0W8bHjju/2+sG/T3yOvTaF7ZvZczeM4+F46m8zv EcyuiM7eoiDo2tTsJIL4EAVE5DG4MJmveCEgyNXlBYkcFvTOw9bBXqaJa EV0ByS33JXNvBaoWlFy1trmy6HeHYInoArgQ1KjlxZE4FcRDtI+SAE7qy luXc+m83NtZUb7TqPZdNTThdqiLKrM/aW3uthS2rDdC4nmOE52RqzsUWa g==; X-CSE-ConnectionGUID: x0ztkztsTW6L+6UTkGEWNQ== X-CSE-MsgGUID: kb6l9vcJTw+i0Lb1mxsOYw== X-IronPort-AV: E=McAfee;i="6700,10204,11438"; a="49566637" X-IronPort-AV: E=Sophos;i="6.15,302,1739865600"; d="scan'208";a="49566637" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2025 03:29:12 -0700 X-CSE-ConnectionGUID: K0NXmz3yQGqZNd/LaV/iJA== X-CSE-MsgGUID: YnzgoaVORCePeeTjE9lLsg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,302,1739865600"; d="scan'208";a="144905230" Received: from emr-bkc.sh.intel.com ([10.112.230.82]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2025 03:29:07 -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 Subject: [PATCH v5 02/10] memory: Change memory_region_set_ram_discard_manager() to return the result Date: Tue, 20 May 2025 18:28:42 +0800 Message-ID: <20250520102856.132417-3-chenyi.qiang@intel.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250520102856.132417-1-chenyi.qiang@intel.com> References: <20250520102856.132417-1-chenyi.qiang@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Chenyi Qiang --- Changes in v5: - Nit in commit message (return false -> -EBUSY) - Add set_ram_discard_manager(NULL) when ram_block_discard_range() fails. Changes in v4: - No change. Changes in v3: - Move set_ram_discard_manager() up to avoid a g_free() - Clean up set_ram_discard_manager() definition Changes in v2: - newly added. --- 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 b961c4076a..896948deb1 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 63b983efcd..b45b508dce 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