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 A3A6BBA49 for ; Tue, 7 Mar 2023 18:43:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B297C433D2; Tue, 7 Mar 2023 18:43:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678214607; bh=Kf4U3z9o1Jis115Nt0QAsxq4847OoVkrqJJWO984S1M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LLOS9VjjYc4b3aGwhx5RnGkIIioGeGvXMRRQyKAe45Y04FQHWJlInL+ZJuJNFtCzE 9fP0aBEG1JdqmVydAKhohGSsvaytyoKa4dClO74Zto6WsYvEp53Xa1E9jou/DPbiWb RSvGbxs5KShkHIml7pVWM05ohBAnfKqPWEVxAgXQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Steve Sistare , Kevin Tian , Jason Gunthorpe , Alex Williamson Subject: [PATCH 6.1 877/885] vfio/type1: restore locked_vm Date: Tue, 7 Mar 2023 18:03:31 +0100 Message-Id: <20230307170039.890414725@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307170001.594919529@linuxfoundation.org> References: <20230307170001.594919529@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Steve Sistare commit 90fdd158a695d70403163f9a0e4efc5b20f3fd3e upstream. When a vfio container is preserved across exec or fork-exec, the new task's mm has a locked_vm count of 0. After a dma vaddr is updated using VFIO_DMA_MAP_FLAG_VADDR, locked_vm remains 0, and the pinned memory does not count against the task's RLIMIT_MEMLOCK. To restore the correct locked_vm count, when VFIO_DMA_MAP_FLAG_VADDR is used and the dma's mm has changed, add the dma's locked_vm count to the new mm->locked_vm, subject to the rlimit, and subtract it from the old mm->locked_vm. Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr") Cc: stable@vger.kernel.org Signed-off-by: Steve Sistare Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Link: https://lore.kernel.org/r/1675184289-267876-5-git-send-email-steven.sistare@oracle.com Signed-off-by: Alex Williamson Signed-off-by: Greg Kroah-Hartman --- drivers/vfio/vfio_iommu_type1.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -1591,6 +1591,38 @@ static bool vfio_iommu_iova_dma_valid(st return list_empty(iova); } +static int vfio_change_dma_owner(struct vfio_dma *dma) +{ + struct task_struct *task = current->group_leader; + struct mm_struct *mm = current->mm; + long npage = dma->locked_vm; + bool lock_cap; + int ret; + + if (mm == dma->mm) + return 0; + + lock_cap = capable(CAP_IPC_LOCK); + ret = mm_lock_acct(task, mm, lock_cap, npage); + if (ret) + return ret; + + if (mmget_not_zero(dma->mm)) { + mm_lock_acct(dma->task, dma->mm, dma->lock_cap, -npage); + mmput(dma->mm); + } + + if (dma->task != task) { + put_task_struct(dma->task); + dma->task = get_task_struct(task); + } + mmdrop(dma->mm); + dma->mm = mm; + mmgrab(dma->mm); + dma->lock_cap = lock_cap; + return 0; +} + static int vfio_dma_do_map(struct vfio_iommu *iommu, struct vfio_iommu_type1_dma_map *map) { @@ -1640,6 +1672,9 @@ static int vfio_dma_do_map(struct vfio_i dma->size != size) { ret = -EINVAL; } else { + ret = vfio_change_dma_owner(dma); + if (ret) + goto out_unlock; dma->vaddr = vaddr; dma->vaddr_invalid = false; iommu->vaddr_invalid_count--;