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um: virt-pci: don't do DMA from stack

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When enabling VMAP_STACK, SG helpers immediately complained
that we were doing DMA from stack. Use per-CPU variables to
avoid that.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Johannes Berg 2021-08-11 16:58:25 +02:00 committed by Richard Weinberger
parent 1568cb0e6d
commit 4a22c4cebd
1 changed files with 78 additions and 26 deletions
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100
arch/um/drivers/virt-pci.c
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@ -56,6 +56,13 @@ static unsigned long um_pci_msi_used[BITS_TO_LONGS(MAX_MSI_VECTORS)];
#define UM_VIRT_PCI_MAXDELAY 40000 #define UM_VIRT_PCI_MAXDELAY 40000
struct um_pci_message_buffer {
struct virtio_pcidev_msg hdr;
u8 data[8];
};
static struct um_pci_message_buffer __percpu *um_pci_msg_bufs;
static int um_pci_send_cmd(struct um_pci_device *dev, static int um_pci_send_cmd(struct um_pci_device *dev,
struct virtio_pcidev_msg *cmd, struct virtio_pcidev_msg *cmd,
unsigned int cmd_size, unsigned int cmd_size,
@ -68,11 +75,12 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
[1] = extra ? &extra_sg : &in_sg, [1] = extra ? &extra_sg : &in_sg,
[2] = extra ? &in_sg : NULL, [2] = extra ? &in_sg : NULL,
}; };
struct um_pci_message_buffer *buf;
int delay_count = 0; int delay_count = 0;
int ret, len; int ret, len;
bool posted; bool posted;
if (WARN_ON(cmd_size < sizeof(*cmd))) if (WARN_ON(cmd_size < sizeof(*cmd) || cmd_size > sizeof(*buf)))
return -EINVAL; return -EINVAL;
switch (cmd->op) { switch (cmd->op) {
@ -88,6 +96,9 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
break; break;
} }
buf = get_cpu_var(um_pci_msg_bufs);
memcpy(buf, cmd, cmd_size);
if (posted) { if (posted) {
u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC); u8 *ncmd = kmalloc(cmd_size + extra_size, GFP_ATOMIC);
@ -102,7 +113,10 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
} else { } else {
/* try without allocating memory */ /* try without allocating memory */
posted = false; posted = false;
cmd = (void *)buf;
} }
} else {
cmd = (void *)buf;
} }
sg_init_one(&out_sg, cmd, cmd_size); sg_init_one(&out_sg, cmd, cmd_size);
@ -118,11 +132,12 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
posted ? cmd : HANDLE_NO_FREE(cmd), posted ? cmd : HANDLE_NO_FREE(cmd),
GFP_ATOMIC); GFP_ATOMIC);
if (ret) if (ret)
return ret; goto out;
if (posted) { if (posted) {
virtqueue_kick(dev->cmd_vq); virtqueue_kick(dev->cmd_vq);
return 0; ret = 0;
goto out;
} }
/* kick and poll for getting a response on the queue */ /* kick and poll for getting a response on the queue */
@ -148,6 +163,8 @@ static int um_pci_send_cmd(struct um_pci_device *dev,
} }
clear_bit(UM_PCI_STAT_WAITING, &dev->status); clear_bit(UM_PCI_STAT_WAITING, &dev->status);
out:
put_cpu_var(um_pci_msg_bufs);
return ret; return ret;
} }
@ -161,12 +178,17 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
.size = size, .size = size,
.addr = offset, .addr = offset,
}; };
/* maximum size - we may only use parts of it */ /* buf->data is maximum size - we may only use parts of it */
u8 data[8]; struct um_pci_message_buffer *buf;
u8 *data;
unsigned long ret = ~0ULL;
if (!dev) if (!dev)
return ~0ULL; return ~0ULL;
buf = get_cpu_var(um_pci_msg_bufs);
data = buf->data;
memset(data, 0xff, sizeof(data)); memset(data, 0xff, sizeof(data));
switch (size) { switch (size) {
@ -179,27 +201,34 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
break; break;
default: default:
WARN(1, "invalid config space read size %d\n", size); WARN(1, "invalid config space read size %d\n", size);
return ~0ULL; goto out;
} }
if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, if (um_pci_send_cmd(dev, &hdr, sizeof(hdr), NULL, 0, data, 8))
data, sizeof(data))) goto out;
return ~0ULL;
switch (size) { switch (size) {
case 1: case 1:
return data[0]; ret = data[0];
break;
case 2: case 2:
return le16_to_cpup((void *)data); ret = le16_to_cpup((void *)data);
break;
case 4: case 4:
return le32_to_cpup((void *)data); ret = le32_to_cpup((void *)data);
break;
#ifdef CONFIG_64BIT #ifdef CONFIG_64BIT
case 8: case 8:
return le64_to_cpup((void *)data); ret = le64_to_cpup((void *)data);
break;
#endif #endif
default: default:
return ~0ULL; break;
} }
out:
put_cpu_var(um_pci_msg_bufs);
return ret;
} }
static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size, static void um_pci_cfgspace_write(void *priv, unsigned int offset, int size,
@ -272,8 +301,13 @@ static void um_pci_bar_copy_from(void *priv, void *buffer,
static unsigned long um_pci_bar_read(void *priv, unsigned int offset, static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
int size) int size)
{ {
/* maximum size - we may only use parts of it */ /* buf->data is maximum size - we may only use parts of it */
u8 data[8]; struct um_pci_message_buffer *buf;
u8 *data;
unsigned long ret = ~0ULL;
buf = get_cpu_var(um_pci_msg_bufs);
data = buf->data;
switch (size) { switch (size) {
case 1: case 1:
@ -285,25 +319,33 @@ static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
break; break;
default: default:
WARN(1, "invalid config space read size %d\n", size); WARN(1, "invalid config space read size %d\n", size);
return ~0ULL; goto out;
} }
um_pci_bar_copy_from(priv, data, offset, size); um_pci_bar_copy_from(priv, data, offset, size);
switch (size) { switch (size) {
case 1: case 1:
return data[0]; ret = data[0];
break;
case 2: case 2:
return le16_to_cpup((void *)data); ret = le16_to_cpup((void *)data);
break;
case 4: case 4:
return le32_to_cpup((void *)data); ret = le32_to_cpup((void *)data);
break;
#ifdef CONFIG_64BIT #ifdef CONFIG_64BIT
case 8: case 8:
return le64_to_cpup((void *)data); ret = le64_to_cpup((void *)data);
break;
#endif #endif
default: default:
return ~0ULL; break;
} }
out:
put_cpu_var(um_pci_msg_bufs);
return ret;
} }
static void um_pci_bar_copy_to(void *priv, unsigned int offset, static void um_pci_bar_copy_to(void *priv, unsigned int offset,
@ -823,10 +865,16 @@ static int um_pci_init(void)
"No virtio device ID configured for PCI - no PCI support\n")) "No virtio device ID configured for PCI - no PCI support\n"))
return 0; return 0;
bridge = pci_alloc_host_bridge(0); um_pci_msg_bufs = alloc_percpu(struct um_pci_message_buffer);
if (!bridge) if (!um_pci_msg_bufs)
return -ENOMEM; return -ENOMEM;
bridge = pci_alloc_host_bridge(0);
if (!bridge) {
err = -ENOMEM;
goto free;
}
um_pci_fwnode = irq_domain_alloc_named_fwnode("um-pci"); um_pci_fwnode = irq_domain_alloc_named_fwnode("um-pci");
if (!um_pci_fwnode) { if (!um_pci_fwnode) {
err = -ENOMEM; err = -ENOMEM;
@ -878,8 +926,11 @@ free:
irq_domain_remove(um_pci_inner_domain); irq_domain_remove(um_pci_inner_domain);
if (um_pci_fwnode) if (um_pci_fwnode)
irq_domain_free_fwnode(um_pci_fwnode); irq_domain_free_fwnode(um_pci_fwnode);
if (bridge) {
pci_free_resource_list(&bridge->windows); pci_free_resource_list(&bridge->windows);
pci_free_host_bridge(bridge); pci_free_host_bridge(bridge);
}
free_percpu(um_pci_msg_bufs);
return err; return err;
} }
module_init(um_pci_init); module_init(um_pci_init);
@ -891,5 +942,6 @@ static void um_pci_exit(void)
irq_domain_remove(um_pci_inner_domain); irq_domain_remove(um_pci_inner_domain);
pci_free_resource_list(&bridge->windows); pci_free_resource_list(&bridge->windows);
pci_free_host_bridge(bridge); pci_free_host_bridge(bridge);
free_percpu(um_pci_msg_bufs);
} }
module_exit(um_pci_exit); module_exit(um_pci_exit);