From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7594E39A7F9; Mon, 27 Apr 2026 08:54:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777280062; cv=none; b=DMrY1Rlgjg+9Jv9BgXUifRGoY2ZXrV8iuIgzn0brWy7890tKlAbb/5IuSrX27lg4HP25heXuENqLU/8oLYp3NnSDilYe5tQZ0z296pUyG+ZF5waGAtHfogy1QJ5+9fIHZZwnULU7yr1G1niIDnojzzAfft4kNFC5WY5wjK0X3us= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777280062; c=relaxed/simple; bh=5JldwqOz6d/PQ2tCB2GyOBMM1LTQvdiuh2P5MyoFZj8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dnTf56MBu3WqQCPbxz6+eCvzFHtqZmh/BnwNa0jOxs0BsVA51Ir3J8s1mdu4gS9/m0ACfIbaj6vwXwruN8DG5LzHrDRgQR2iogjmSYb2t+t9+rAHTvqs1Hgut5bz8kaBz905ugipC6vuHEynPeVz3+Vx288c6sbCaOPH7MwguAQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kQyUFNwH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kQyUFNwH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88A8AC2BCC7; Mon, 27 Apr 2026 08:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777280062; bh=5JldwqOz6d/PQ2tCB2GyOBMM1LTQvdiuh2P5MyoFZj8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kQyUFNwHTNq2nEzzkyEHIG3YexRLfjKtRrIW3nX86jeTpN/EsGThSRpCTBF8UY6Ac Qndek+3O6W4fP1zkWtklb4FSyaxwmhYzpQKK4L/e8zG5Pg1ealJqcMHUxhzEoWoA0x kjceO2++YsQi0chVfMPOzH3IGpJcgNxKtR1L10ElbvTgQ3BLeECbkmH5PlyZEOFJ7A 2tn7VyXCq704khvDIPMz1oRf5SYfJKsYenfHmTqQoe3wZe7uhhZDRhsxgR9iEd6YIn 324My719A/DRmp3L0JnZHaSUGgk4IUYCV4kswIM0gEYfLQGnVLOer0Tj1anC6qCC0A dhSDPubODbADA== From: "Aneesh Kumar K.V (Arm)" To: linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: "Aneesh Kumar K.V (Arm)" , Alexey Kardashevskiy , Catalin Marinas , Dan Williams , Jason Gunthorpe , Joerg Roedel , Jonathan Cameron , Marc Zyngier , Nicolin Chen , Pranjal Shrivastava , Robin Murphy , Samuel Ortiz , Steven Price , Suzuki K Poulose , Will Deacon , Xu Yilun Subject: [RFC PATCH v4 04/16] iommu/arm-smmu-v3: Track realm pSMMU users with refcount_t Date: Mon, 27 Apr 2026 14:23:32 +0530 Message-ID: <20260427085344.941627-5-aneesh.kumar@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260427085344.941627-1-aneesh.kumar@kernel.org> References: <20260427085344.941627-1-aneesh.kumar@kernel.org> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Replace the realm pSMMU active-state boolean with a refcount so activation/deactivation is tied to actual Realm vIOMMU lifetime. - add realm_mutex and realm_users (refcount_t) to struct arm_smmu_device - on first Realm init, activate pSMMU and set realm_users to 1 - on subsequent Realm inits, increment realm_users - on Realm viommu destroy, decrement realm_users and call rmi_psmmu_deactivate() when the last user drops the count to 0 This removes duplicated state tracking and ensures pSMMU is deactivated only after the last Realm user is gone. Signed-off-by: Aneesh Kumar K.V (Arm) --- arch/arm64/include/asm/rmi_cmds.h | 1 + arch/arm64/kernel/rmi.c | 12 ++++++ .../iommu/arm/arm-smmu-v3/arm-smmu-v3-realm.c | 39 +++++++++++++++---- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 +- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 4 +- 5 files changed, 50 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/asm/rmi_cmds.h index 659d68ad5f1d..205fc200d1db 100644 --- a/arch/arm64/include/asm/rmi_cmds.h +++ b/arch/arm64/include/asm/rmi_cmds.h @@ -865,6 +865,7 @@ static inline unsigned long rmi_psmmu_event_consume(unsigned long psmmu_phys, int rmi_psmmu_activate(unsigned long psmmu_phys, unsigned long psmmu_params_phys, unsigned long *rmi_ret); +int rmi_psmmu_deactivate(unsigned long psmmu_phys, unsigned long *rmi_ret); int rmi_psmmu_st_l2_create(unsigned long psmmu_phys, unsigned long stream_id, unsigned long *rmi_ret); int rmi_psmmu_st_l2_destroy(unsigned long psmmu_phys, diff --git a/arch/arm64/kernel/rmi.c b/arch/arm64/kernel/rmi.c index cc4050db5a6a..884ab3f99f2f 100644 --- a/arch/arm64/kernel/rmi.c +++ b/arch/arm64/kernel/rmi.c @@ -436,6 +436,18 @@ int rmi_psmmu_activate(unsigned long psmmu_phys, return 0; } +int rmi_psmmu_deactivate(unsigned long psmmu_phys, unsigned long *rmi_ret) +{ + struct rmi_sro_state *sro __free(sro) = + rmi_sro_init(SMC_RMI_PSMMU_DEACTIVATE, psmmu_phys); + if (!sro) + return -ENOMEM; + + *rmi_ret = rmi_sro_execute(sro); + + return 0; +} + int rmi_psmmu_st_l2_create(unsigned long psmmu_phys, unsigned long stream_id, unsigned long *rmi_ret) { diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-realm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-realm.c index 6f8de7cead9d..dfff493f96d0 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-realm.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-realm.c @@ -124,9 +124,25 @@ void arm_smmu_setup_realm_irqs(struct arm_smmu_device *smmu) } } +static bool arm_realm_smmu_active(struct arm_smmu_device *smmu) +{ + lockdep_assert_held(&smmu->realm_mutex); + return refcount_read(&smmu->realm_users) > 0; +} + static void arm_realm_smmu_v3_destroy(struct iommufd_viommu *viommu) { - /* When we add refcount psmmu deactivate here. */ + unsigned long rmi_ret; + struct arm_smmu_device *smmu = + container_of(viommu->iommu_dev, struct arm_smmu_device, iommu); + + guard(mutex)(&smmu->realm_mutex); + if (WARN_ON(!arm_realm_smmu_active(smmu))) + return; + + if (refcount_dec_and_test(&smmu->realm_users) && + (rmi_psmmu_deactivate(smmu->base_phys, &rmi_ret) || rmi_ret)) + dev_warn(smmu->dev, "failed to deactivate realm pSMMU\n"); } static void arm_realm_smmu_v3_vdevice_destroy(struct iommufd_vdevice *vdev) @@ -140,7 +156,8 @@ static void arm_realm_smmu_v3_vdevice_destroy(struct iommufd_vdevice *vdev) unsigned long rmi_ret = 0; int ret; - if (!smmu->realm_initialized) + guard(mutex)(&smmu->realm_mutex); + if (!arm_realm_smmu_active(smmu)) return; ret = rmi_psmmu_st_l2_destroy(smmu->base_phys, @@ -168,7 +185,8 @@ static int arm_realm_smmu_v3_vdevice_init(struct iommufd_vdevice *vdev) unsigned long rmi_ret = 0; int ret; - if (!smmu->realm_initialized) + guard(mutex)(&smmu->realm_mutex); + if (!arm_realm_smmu_active(smmu)) return -EINVAL; ret = rmi_psmmu_st_l2_create(smmu->base_phys, @@ -229,12 +247,17 @@ int arm_realm_smmu_v3_init(struct iommufd_viommu *viommu, if (!(smmu->features & ARM_SMMU_FEAT_RME)) return -EOPNOTSUPP; - if (smmu->realm_initialized) + mutex_lock(&smmu->realm_mutex); + if (arm_realm_smmu_active(smmu)) { + refcount_inc(&smmu->realm_users); goto psmmu_already_active; + } params = (struct rmi_psmmu_params *)get_zeroed_page(GFP_KERNEL); - if (!params) - return -ENOMEM; + if (!params) { + ret = -ENOMEM; + goto out_unlock; + } /* No ATS and PRI support */ if (!(smmu->features & ARM_SMMU_FEAT_MSI)) @@ -261,12 +284,14 @@ int arm_realm_smmu_v3_init(struct iommufd_viommu *viommu, dev_warn(smmu->dev, "failed to activate realm pSMMU\n"); ret = -EIO; } else { - smmu->realm_initialized = true; + refcount_set(&smmu->realm_users, 1); } out_free: free_page((unsigned long)params); psmmu_already_active: if (!ret) viommu->ops = &arm_realm_smmu_v3_ops; +out_unlock: + mutex_unlock(&smmu->realm_mutex); return ret; } diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index 1e3d4d682e32..e458c3818c34 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -3946,6 +3946,8 @@ static int arm_smmu_init_structures(struct arm_smmu_device *smmu) int ret; mutex_init(&smmu->streams_mutex); + mutex_init(&smmu->realm_mutex); + refcount_set(&smmu->realm_users, 0); smmu->streams = RB_ROOT; ret = arm_smmu_init_queues(smmu); @@ -3956,7 +3958,6 @@ static int arm_smmu_init_structures(struct arm_smmu_device *smmu) if (ret) return ret; - smmu->realm_initialized = false; if (smmu->impl_ops && smmu->impl_ops->init_structures) return smmu->impl_ops->init_structures(smmu); diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index d528b3212d38..b5d0e1341236 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -13,6 +13,7 @@ #include #include #include +#include #include struct arm_smmu_device; @@ -812,7 +813,8 @@ struct arm_smmu_device { struct rb_root streams; struct mutex streams_mutex; - bool realm_initialized; + struct mutex realm_mutex; + refcount_t realm_users; }; struct arm_smmu_stream { -- 2.43.0