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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 275AFC021AA for ; Tue, 18 Feb 2025 22:11:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TsmTzYzOA/h2nBvEn/GmishOA6WlMy+9II2XUP0uX6Q=; b=b34hNX+gnhsQG6hGr1sEH4KpD5 H9gOIOhGOY+UqS6bqcmFweNMc+jjIHpu9mNvxqqNoqKMdySFWb6cSLzVm0XDfpebqavTJ80HXiiiV vD3o3RiTQGAZWGLffT3H5L3mH21m0P0MjUgP4gFCNxoNWhUB56QM8Qbat58d5iWu0mm66dmNrFPyY szwvLF5aTJn5OmOZEtS2JiaaPURx+XNKLnLCAeVvE7jNKr4GXfbqFJGHVt3A57tKui5xEXiOc8qYy w0Tk3SVkmg2lkWu8Go0//T/buJAwLa0ffr6dpFxMFo1CiwUKfjkTcntGsOhWbf+CQd3n3s4hEV5g4 nQ1XMW0Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tkVo3-0000000A6ch-2UEq; Tue, 18 Feb 2025 22:11:07 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tkUCT-00000009let-0ZZH for linux-um@lists.infradead.org; Tue, 18 Feb 2025 20:28:14 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 8A990A41B00; Tue, 18 Feb 2025 20:26:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85831C4CEE4; Tue, 18 Feb 2025 20:28:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739910492; bh=DFWtttygelaZtQfN6lEq/ZJlHYl+TAZeqCnSmLKij5g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MA17id+ePHujI2SSpECMNk7ivzIZlRT24l32EapKmDDHIwD8Lu64JlxvadFigVQ4d H5iOYcDxW9T/LfnfPzNS3wIu5uUo+k4cI0tANBAMo3wq9Z1lpLFumjtk//Da/hmtEE T001zqN3q7Q8v/uVUsX8CiRy/BlNmtcd+KyVp61/RlnLodGrGgIBU4G8y9oYLuSv0K ioPx5SFIrttrDTzgHmg6vXklN+rvQENU5avSN2u1NdeIZR7boohMMoutG+fikLb0WZ zuFXSoM4uN/+RLNaId5BLjyV7JNen0/ZDD5shMLSz2rOcON703RO6DT23+G23bnuTR 1AyKNOsFaeysg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Johannes Berg , Richard Weinberger , Sasha Levin , anton.ivanov@cambridgegreys.com, johannes@sipsolutions.net, mst@redhat.com, jiri@resnulli.us, tglx@linutronix.de, viro@zeniv.linux.org.uk, krzysztof.kozlowski@linaro.org, herve.codina@bootlin.com, linux-um@lists.infradead.org Subject: [PATCH AUTOSEL 6.6 14/17] um: virt-pci: don't use kmalloc() Date: Tue, 18 Feb 2025 15:27:38 -0500 Message-Id: <20250218202743.3593296-14-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250218202743.3593296-1-sashal@kernel.org> References: <20250218202743.3593296-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.78 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250218_122813_310399_B12A0F2D X-CRM114-Status: GOOD ( 24.05 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org From: Johannes Berg [ Upstream commit 5b166b782d327f4b66190cc43afd3be36f2b3b7a ] This code can be called deep in the IRQ handling, for example, and then cannot normally use kmalloc(). Have its own pre-allocated memory and use from there instead so this doesn't occur. Only in the (very rare) case of memcpy_toio() we'd still need to allocate memory. Link: https://patch.msgid.link/20250110125550.32479-6-johannes@sipsolutions.net Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/virt-pci.c | 198 +++++++++++++++++++------------------ 1 file changed, 102 insertions(+), 96 deletions(-) diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c index 97a37c0629972..3a02b5e2f78ba 100644 --- a/arch/um/drivers/virt-pci.c +++ b/arch/um/drivers/virt-pci.c @@ -25,8 +25,10 @@ #define MAX_IRQ_MSG_SIZE (sizeof(struct virtio_pcidev_msg) + sizeof(u32)) #define NUM_IRQ_MSGS 10 -#define HANDLE_NO_FREE(ptr) ((void *)((unsigned long)(ptr) | 1)) -#define HANDLE_IS_NO_FREE(ptr) ((unsigned long)(ptr) & 1) +struct um_pci_message_buffer { + struct virtio_pcidev_msg hdr; + u8 data[8]; +}; struct um_pci_device { struct virtio_device *vdev; @@ -36,6 +38,11 @@ struct um_pci_device { struct virtqueue *cmd_vq, *irq_vq; +#define UM_PCI_WRITE_BUFS 20 + struct um_pci_message_buffer bufs[UM_PCI_WRITE_BUFS + 1]; + void *extra_ptrs[UM_PCI_WRITE_BUFS + 1]; + DECLARE_BITMAP(used_bufs, UM_PCI_WRITE_BUFS); + #define UM_PCI_STAT_WAITING 0 unsigned long status; @@ -61,12 +68,40 @@ static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)]; static unsigned int um_pci_max_delay_us = 40000; module_param_named(max_delay_us, um_pci_max_delay_us, uint, 0644); -struct um_pci_message_buffer { - struct virtio_pcidev_msg hdr; - u8 data[8]; -}; +static int um_pci_get_buf(struct um_pci_device *dev, bool *posted) +{ + int i; + + for (i = 0; i < UM_PCI_WRITE_BUFS; i++) { + if (!test_and_set_bit(i, dev->used_bufs)) + return i; + } -static struct um_pci_message_buffer __percpu *um_pci_msg_bufs; + *posted = false; + return UM_PCI_WRITE_BUFS; +} + +static void um_pci_free_buf(struct um_pci_device *dev, void *buf) +{ + int i; + + if (buf == &dev->bufs[UM_PCI_WRITE_BUFS]) { + kfree(dev->extra_ptrs[UM_PCI_WRITE_BUFS]); + dev->extra_ptrs[UM_PCI_WRITE_BUFS] = NULL; + return; + } + + for (i = 0; i < UM_PCI_WRITE_BUFS; i++) { + if (buf == &dev->bufs[i]) { + kfree(dev->extra_ptrs[i]); + dev->extra_ptrs[i] = NULL; + WARN_ON(!test_and_clear_bit(i, dev->used_bufs)); + return; + } + } + + WARN_ON(1); +} static int um_pci_send_cmd(struct um_pci_device *dev, struct virtio_pcidev_msg *cmd, @@ -82,7 +117,9 @@ static int um_pci_send_cmd(struct um_pci_device *dev, }; struct um_pci_message_buffer *buf; int delay_count = 0; + bool bounce_out; int ret, len; + int buf_idx; bool posted; if (WARN_ON(cmd_size < sizeof(*cmd) || cmd_size > sizeof(*buf))) @@ -101,26 +138,28 @@ static int um_pci_send_cmd(struct um_pci_device *dev, break; } - buf = get_cpu_var(um_pci_msg_bufs); - if (buf) - memcpy(buf, cmd, cmd_size); + bounce_out = !posted && cmd_size <= sizeof(*cmd) && + out && out_size <= sizeof(buf->data); - if (posted) { - u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC); - - if (ncmd) { - memcpy(ncmd, cmd, cmd_size); - if (extra) - memcpy(ncmd + cmd_size, extra, extra_size); - cmd = (void *)ncmd; - cmd_size += extra_size; - extra = NULL; - extra_size = 0; - } else { - /* try without allocating memory */ - posted = false; - cmd = (void *)buf; + buf_idx = um_pci_get_buf(dev, &posted); + buf = &dev->bufs[buf_idx]; + memcpy(buf, cmd, cmd_size); + + if (posted && extra && extra_size > sizeof(buf) - cmd_size) { + dev->extra_ptrs[buf_idx] = kmemdup(extra, extra_size, + GFP_ATOMIC); + + if (!dev->extra_ptrs[buf_idx]) { + um_pci_free_buf(dev, buf); + return -ENOMEM; } + extra = dev->extra_ptrs[buf_idx]; + } else if (extra && extra_size <= sizeof(buf) - cmd_size) { + memcpy((u8 *)buf + cmd_size, extra, extra_size); + cmd_size += extra_size; + extra_size = 0; + extra = NULL; + cmd = (void *)buf; } else { cmd = (void *)buf; } @@ -128,39 +167,40 @@ static int um_pci_send_cmd(struct um_pci_device *dev, sg_init_one(&out_sg, cmd, cmd_size); if (extra) sg_init_one(&extra_sg, extra, extra_size); - if (out) + /* allow stack for small buffers */ + if (bounce_out) + sg_init_one(&in_sg, buf->data, out_size); + else if (out) sg_init_one(&in_sg, out, out_size); /* add to internal virtio queue */ ret = virtqueue_add_sgs(dev->cmd_vq, sgs_list, extra ? 2 : 1, out ? 1 : 0, - posted ? cmd : HANDLE_NO_FREE(cmd), - GFP_ATOMIC); + cmd, GFP_ATOMIC); if (ret) { - if (posted) - kfree(cmd); - goto out; + um_pci_free_buf(dev, buf); + return ret; } if (posted) { virtqueue_kick(dev->cmd_vq); - ret = 0; - goto out; + return 0; } /* kick and poll for getting a response on the queue */ set_bit(UM_PCI_STAT_WAITING, &dev->status); virtqueue_kick(dev->cmd_vq); + ret = 0; while (1) { void *completed = virtqueue_get_buf(dev->cmd_vq, &len); - if (completed == HANDLE_NO_FREE(cmd)) + if (completed == buf) break; - if (completed && !HANDLE_IS_NO_FREE(completed)) - kfree(completed); + if (completed) + um_pci_free_buf(dev, completed); if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) || ++delay_count > um_pci_max_delay_us, @@ -172,8 +212,11 @@ static int um_pci_send_cmd(struct um_pci_device *dev, } clear_bit(UM_PCI_STAT_WAITING, &dev->status); -out: - put_cpu_var(um_pci_msg_bufs); + if (bounce_out) + memcpy(out, buf->data, out_size); + + um_pci_free_buf(dev, buf); + return ret; } @@ -187,20 +230,13 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset, .size = size, .addr = offset, }; - /* buf->data is maximum size - we may only use parts of it */ - struct um_pci_message_buffer *buf; - u8 *data; - unsigned long ret = ULONG_MAX; - size_t bytes = sizeof(buf->data); + /* max 8, we might not use it all */ + u8 data[8]; if (!dev) return ULONG_MAX; - buf = get_cpu_var(um_pci_msg_bufs); - data = buf->data; - - if (buf) - memset(data, 0xff, bytes); + memset(data, 0xff, sizeof(data)); switch (size) { case 1: @@ -212,34 +248,26 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset, break; default: WARN(1, "invalid config space read size %d\n", size); - goto out; + return ULONG_MAX; } - if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, bytes)) - goto out; + if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, size)) + return ULONG_MAX; switch (size) { case 1: - ret = data[0]; - break; + return data[0]; case 2: - ret = le16_to_cpup((void *)data); - break; + return le16_to_cpup((void *)data); case 4: - ret = le32_to_cpup((void *)data); - break; + return le32_to_cpup((void *)data); #ifdef CONFIG_64BIT case 8: - ret = le64_to_cpup((void *)data); - break; + return le64_to_cpup((void *)data); #endif default: - break; + return ULONG_MAX; } - -out: - put_cpu_var(um_pci_msg_bufs); - return ret; } static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size, @@ -312,13 +340,8 @@ static void um_pci_bar_copy_from(void *priv, void *buffer, static unsigned long um_pci_bar_read(void *priv, unsigned int offset, int size) { - /* buf->data is maximum size - we may only use parts of it */ - struct um_pci_message_buffer *buf; - u8 *data; - unsigned long ret = ULONG_MAX; - - buf = get_cpu_var(um_pci_msg_bufs); - data = buf->data; + /* 8 is maximum size - we may only use parts of it */ + u8 data[8]; switch (size) { case 1: @@ -330,33 +353,25 @@ static unsigned long um_pci_bar_read(void *priv, unsigned int offset, break; default: WARN(1, "invalid config space read size %d\n", size); - goto out; + return ULONG_MAX; } um_pci_bar_copy_from(priv, data, offset, size); switch (size) { case 1: - ret = data[0]; - break; + return data[0]; case 2: - ret = le16_to_cpup((void *)data); - break; + return le16_to_cpup((void *)data); case 4: - ret = le32_to_cpup((void *)data); - break; + return le32_to_cpup((void *)data); #ifdef CONFIG_64BIT case 8: - ret = le64_to_cpup((void *)data); - break; + return le64_to_cpup((void *)data); #endif default: - break; + return ULONG_MAX; } - -out: - put_cpu_var(um_pci_msg_bufs); - return ret; } static void um_pci_bar_copy_to(void *priv, unsigned int offset, @@ -523,11 +538,8 @@ static void um_pci_cmd_vq_cb(struct virtqueue *vq) if (test_bit(UM_PCI_STAT_WAITING, &dev->status)) return; - while ((cmd = virtqueue_get_buf(vq, &len))) { - if (WARN_ON(HANDLE_IS_NO_FREE(cmd))) - continue; - kfree(cmd); - } + while ((cmd = virtqueue_get_buf(vq, &len))) + um_pci_free_buf(dev, cmd); } static void um_pci_irq_vq_cb(struct virtqueue *vq) @@ -1000,10 +1012,6 @@ static int __init um_pci_init(void) "No virtio device ID configured for PCI - no PCI support\n")) return 0; - um_pci_msg_bufs = alloc_percpu(struct um_pci_message_buffer); - if (!um_pci_msg_bufs) - return -ENOMEM; - bridge = pci_alloc_host_bridge(0); if (!bridge) { err = -ENOMEM; @@ -1065,7 +1073,6 @@ static int __init um_pci_init(void) pci_free_resource_list(&bridge->windows); pci_free_host_bridge(bridge); } - free_percpu(um_pci_msg_bufs); return err; } module_init(um_pci_init); @@ -1077,6 +1084,5 @@ static void __exit um_pci_exit(void) irq_domain_remove(um_pci_inner_domain); pci_free_resource_list(&bridge->windows); pci_free_host_bridge(bridge); - free_percpu(um_pci_msg_bufs); } module_exit(um_pci_exit); -- 2.39.5