um: virt-pci: don't use kmalloc()
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 <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Johannes Berg
Richard Weinberger
parent
f82a9e7b9f
commit
5b166b782d
1 changed files with 101 additions and 95 deletions
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@ -25,8 +25,10 @@
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#define MAX_IRQ_MSG_SIZE (sizeof(struct virtio_pcidev_msg) + sizeof(u32))
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#define NUM_IRQ_MSGS 10
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#define HANDLE_NO_FREE(ptr) ((void *)((unsigned long)(ptr) | 1))
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#define HANDLE_IS_NO_FREE(ptr) ((unsigned long)(ptr) & 1)
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struct um_pci_message_buffer {
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struct virtio_pcidev_msg hdr;
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u8 data[8];
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};
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struct um_pci_device {
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struct virtio_device *vdev;
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@ -36,6 +38,11 @@ struct um_pci_device {
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struct virtqueue *cmd_vq, *irq_vq;
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#define UM_PCI_WRITE_BUFS 20
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struct um_pci_message_buffer bufs[UM_PCI_WRITE_BUFS + 1];
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void *extra_ptrs[UM_PCI_WRITE_BUFS + 1];
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DECLARE_BITMAP(used_bufs, UM_PCI_WRITE_BUFS);
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#define UM_PCI_STAT_WAITING 0
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unsigned long status;
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@ -61,12 +68,40 @@ static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)];
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static unsigned int um_pci_max_delay_us = 40000;
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module_param_named(max_delay_us, um_pci_max_delay_us, uint, 0644);
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struct um_pci_message_buffer {
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struct virtio_pcidev_msg hdr;
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u8 data[8];
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};
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static int um_pci_get_buf(struct um_pci_device *dev, bool *posted)
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{
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int i;
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static struct um_pci_message_buffer __percpu *um_pci_msg_bufs;
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for (i = 0; i < UM_PCI_WRITE_BUFS; i++) {
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if (!test_and_set_bit(i, dev->used_bufs))
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return i;
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}
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*posted = false;
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return UM_PCI_WRITE_BUFS;
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}
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static void um_pci_free_buf(struct um_pci_device *dev, void *buf)
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{
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int i;
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if (buf == &dev->bufs[UM_PCI_WRITE_BUFS]) {
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kfree(dev->extra_ptrs[UM_PCI_WRITE_BUFS]);
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dev->extra_ptrs[UM_PCI_WRITE_BUFS] = NULL;
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return;
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}
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for (i = 0; i < UM_PCI_WRITE_BUFS; i++) {
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if (buf == &dev->bufs[i]) {
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kfree(dev->extra_ptrs[i]);
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dev->extra_ptrs[i] = NULL;
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WARN_ON(!test_and_clear_bit(i, dev->used_bufs));
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return;
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}
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}
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WARN_ON(1);
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}
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static int um_pci_send_cmd(struct um_pci_device *dev,
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struct virtio_pcidev_msg *cmd,
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@ -82,7 +117,9 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
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};
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struct um_pci_message_buffer *buf;
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int delay_count = 0;
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bool bounce_out;
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int ret, len;
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int buf_idx;
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bool posted;
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if (WARN_ON(cmd_size < sizeof(*cmd) || cmd_size > sizeof(*buf)))
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@ -101,26 +138,28 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
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break;
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}
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buf = get_cpu_var(um_pci_msg_bufs);
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if (buf)
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memcpy(buf, cmd, cmd_size);
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bounce_out = !posted && cmd_size <= sizeof(*cmd) &&
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out && out_size <= sizeof(buf->data);
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if (posted) {
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u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC);
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buf_idx = um_pci_get_buf(dev, &posted);
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buf = &dev->bufs[buf_idx];
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memcpy(buf, cmd, cmd_size);
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if (ncmd) {
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memcpy(ncmd, cmd, cmd_size);
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if (extra)
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memcpy(ncmd + cmd_size, extra, extra_size);
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cmd = (void *)ncmd;
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cmd_size += extra_size;
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extra = NULL;
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extra_size = 0;
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} else {
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/* try without allocating memory */
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posted = false;
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cmd = (void *)buf;
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if (posted && extra && extra_size > sizeof(buf) - cmd_size) {
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dev->extra_ptrs[buf_idx] = kmemdup(extra, extra_size,
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GFP_ATOMIC);
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if (!dev->extra_ptrs[buf_idx]) {
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um_pci_free_buf(dev, buf);
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return -ENOMEM;
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}
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extra = dev->extra_ptrs[buf_idx];
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} else if (extra && extra_size <= sizeof(buf) - cmd_size) {
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memcpy((u8 *)buf + cmd_size, extra, extra_size);
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cmd_size += extra_size;
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extra_size = 0;
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extra = NULL;
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cmd = (void *)buf;
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} else {
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cmd = (void *)buf;
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}
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@ -128,39 +167,40 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
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sg_init_one(&out_sg, cmd, cmd_size);
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if (extra)
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sg_init_one(&extra_sg, extra, extra_size);
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if (out)
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/* allow stack for small buffers */
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if (bounce_out)
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sg_init_one(&in_sg, buf->data, out_size);
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else if (out)
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sg_init_one(&in_sg, out, out_size);
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/* add to internal virtio queue */
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ret = virtqueue_add_sgs(dev->cmd_vq, sgs_list,
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extra ? 2 : 1,
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out ? 1 : 0,
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posted ? cmd : HANDLE_NO_FREE(cmd),
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GFP_ATOMIC);
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cmd, GFP_ATOMIC);
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if (ret) {
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if (posted)
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kfree(cmd);
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goto out;
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um_pci_free_buf(dev, buf);
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return ret;
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}
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if (posted) {
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virtqueue_kick(dev->cmd_vq);
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ret = 0;
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goto out;
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return 0;
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}
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/* kick and poll for getting a response on the queue */
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set_bit(UM_PCI_STAT_WAITING, &dev->status);
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virtqueue_kick(dev->cmd_vq);
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ret = 0;
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while (1) {
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void *completed = virtqueue_get_buf(dev->cmd_vq, &len);
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if (completed == HANDLE_NO_FREE(cmd))
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if (completed == buf)
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break;
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if (completed && !HANDLE_IS_NO_FREE(completed))
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kfree(completed);
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if (completed)
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um_pci_free_buf(dev, completed);
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if (WARN_ONCE(virtqueue_is_broken(dev->cmd_vq) ||
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++delay_count > um_pci_max_delay_us,
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@ -172,8 +212,11 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
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}
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clear_bit(UM_PCI_STAT_WAITING, &dev->status);
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out:
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put_cpu_var(um_pci_msg_bufs);
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if (bounce_out)
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memcpy(out, buf->data, out_size);
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um_pci_free_buf(dev, buf);
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return ret;
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}
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@ -187,20 +230,13 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
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.size = size,
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.addr = offset,
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};
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/* buf->data is maximum size - we may only use parts of it */
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struct um_pci_message_buffer *buf;
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u8 *data;
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unsigned long ret = ULONG_MAX;
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size_t bytes = sizeof(buf->data);
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/* max 8, we might not use it all */
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u8 data[8];
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if (!dev)
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return ULONG_MAX;
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buf = get_cpu_var(um_pci_msg_bufs);
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data = buf->data;
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if (buf)
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memset(data, 0xff, bytes);
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memset(data, 0xff, sizeof(data));
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switch (size) {
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case 1:
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@ -212,34 +248,26 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
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break;
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default:
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WARN(1, "invalid config space read size %d\n", size);
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goto out;
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return ULONG_MAX;
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}
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if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, bytes))
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goto out;
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if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, size))
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return ULONG_MAX;
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switch (size) {
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case 1:
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ret = data[0];
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break;
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return data[0];
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case 2:
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ret = le16_to_cpup((void *)data);
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break;
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return le16_to_cpup((void *)data);
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case 4:
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ret = le32_to_cpup((void *)data);
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break;
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return le32_to_cpup((void *)data);
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#ifdef CONFIG_64BIT
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case 8:
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ret = le64_to_cpup((void *)data);
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break;
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return le64_to_cpup((void *)data);
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#endif
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default:
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break;
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return ULONG_MAX;
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}
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out:
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put_cpu_var(um_pci_msg_bufs);
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return ret;
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}
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static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
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@ -312,13 +340,8 @@ static void um_pci_bar_copy_from(void *priv, void *buffer,
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static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
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int size)
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{
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/* buf->data is maximum size - we may only use parts of it */
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struct um_pci_message_buffer *buf;
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u8 *data;
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unsigned long ret = ULONG_MAX;
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buf = get_cpu_var(um_pci_msg_bufs);
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data = buf->data;
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/* 8 is maximum size - we may only use parts of it */
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u8 data[8];
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switch (size) {
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case 1:
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@ -330,33 +353,25 @@ static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
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break;
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default:
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WARN(1, "invalid config space read size %d\n", size);
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goto out;
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return ULONG_MAX;
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}
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um_pci_bar_copy_from(priv, data, offset, size);
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switch (size) {
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case 1:
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ret = data[0];
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break;
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return data[0];
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case 2:
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ret = le16_to_cpup((void *)data);
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break;
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return le16_to_cpup((void *)data);
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case 4:
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ret = le32_to_cpup((void *)data);
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break;
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return le32_to_cpup((void *)data);
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#ifdef CONFIG_64BIT
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case 8:
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ret = le64_to_cpup((void *)data);
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break;
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return le64_to_cpup((void *)data);
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#endif
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default:
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break;
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return ULONG_MAX;
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}
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out:
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put_cpu_var(um_pci_msg_bufs);
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return ret;
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}
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static void um_pci_bar_copy_to(void *priv, unsigned int offset,
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@ -523,11 +538,8 @@ static void um_pci_cmd_vq_cb(struct virtqueue *vq)
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if (test_bit(UM_PCI_STAT_WAITING, &dev->status))
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return;
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while ((cmd = virtqueue_get_buf(vq, &len))) {
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if (WARN_ON(HANDLE_IS_NO_FREE(cmd)))
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continue;
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kfree(cmd);
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}
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while ((cmd = virtqueue_get_buf(vq, &len)))
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um_pci_free_buf(dev, cmd);
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}
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static void um_pci_irq_vq_cb(struct virtqueue *vq)
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@ -1006,10 +1018,6 @@ static int __init um_pci_init(void)
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"No virtio device ID configured for PCI - no PCI support\n"))
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return 0;
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um_pci_msg_bufs = alloc_percpu(struct um_pci_message_buffer);
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if (!um_pci_msg_bufs)
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return -ENOMEM;
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bridge = pci_alloc_host_bridge(0);
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if (!bridge) {
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err = -ENOMEM;
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@ -1070,7 +1078,6 @@ free:
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pci_free_resource_list(&bridge->windows);
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pci_free_host_bridge(bridge);
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}
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free_percpu(um_pci_msg_bufs);
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return err;
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}
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module_init(um_pci_init);
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@ -1082,6 +1089,5 @@ static void __exit um_pci_exit(void)
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irq_domain_remove(um_pci_inner_domain);
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pci_free_resource_list(&bridge->windows);
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pci_free_host_bridge(bridge);
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free_percpu(um_pci_msg_bufs);
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}
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module_exit(um_pci_exit);
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