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kvm tools: Make virtio block device code thread-safe

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In preparation for threaded execution, make the virtio block device code safe
by introducing a per-device mutex.

Cc: Asias He <asias.hejun@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Pekka Enberg
2015-06-01 16:39:42 +01:00
committed by Will Deacon
parent 2932c9eb77
commit 0528c2a76d
1 changed files with 33 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files
virtio-blk.c
+33 -8
View File
@@ -11,8 +11,9 @@
#include <linux/virtio_ring.h>
#include <linux/virtio_blk.h>
#include <inttypes.h>
#include <assert.h>
#include <pthread.h>
#define VIRTIO_BLK_IRQ 14
@@ -21,6 +22,8 @@
#define VIRTIO_BLK_QUEUE_SIZE 128
struct blk_device {
pthread_mutex_t mutex;
struct virtio_blk_config blk_config;
uint32_t host_features;
uint32_t guest_features;
@@ -36,6 +39,8 @@ struct blk_device {
#define DISK_SEG_MAX 126
static struct blk_device blk_device = {
.mutex = PTHREAD_MUTEX_INITIALIZER,
.blk_config = (struct virtio_blk_config) {
/* VIRTIO_BLK_F_SEG_MAX */
.seg_max = DISK_SEG_MAX,
@@ -63,6 +68,10 @@ static bool virtio_blk_pci_io_device_specific_in(void *data, unsigned long offse
static bool virtio_blk_pci_io_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
{
unsigned long offset;
bool ret = true;
if (pthread_mutex_lock(&blk_device.mutex) < 0)
die("pthread_mutex_lock");
offset = port - IOPORT_VIRTIO_BLK;
@@ -71,7 +80,8 @@ static bool virtio_blk_pci_io_in(struct kvm *self, uint16_t port, void *data, in
ioport__write32(data, blk_device.host_features);
break;
case VIRTIO_PCI_GUEST_FEATURES:
return false;
ret = false;
goto out_unlock;
case VIRTIO_PCI_QUEUE_PFN:
ioport__write32(data, blk_device.vqs[blk_device.queue_selector].pfn);
break;
@@ -80,7 +90,8 @@ static bool virtio_blk_pci_io_in(struct kvm *self, uint16_t port, void *data, in
break;
case VIRTIO_PCI_QUEUE_SEL:
case VIRTIO_PCI_QUEUE_NOTIFY:
return false;
ret = false;
goto out_unlock;
case VIRTIO_PCI_STATUS:
ioport__write8(data, blk_device.status);
break;
@@ -92,15 +103,19 @@ static bool virtio_blk_pci_io_in(struct kvm *self, uint16_t port, void *data, in
ioport__write16(data, blk_device.config_vector);
break;
default:
return virtio_blk_pci_io_device_specific_in(data, offset, size, count);
ret = virtio_blk_pci_io_device_specific_in(data, offset, size, count);
goto out_unlock;
};
return true;
out_unlock:
if (pthread_mutex_unlock(&blk_device.mutex) < 0)
die("pthread_mutex_unlock");
return ret;
}
static bool virtio_blk_do_io_request(struct kvm *self, struct virt_queue *queue)
{
struct iovec iov[VIRTIO_BLK_QUEUE_SIZE];
struct virtio_blk_outhdr *req;
uint32_t block_len, block_cnt;
@@ -159,9 +174,14 @@ static void virtio_blk_handle_callback(struct kvm *self, uint16_t queue_index)
kvm__irq_line(self, VIRTIO_BLK_IRQ, 1);
}
static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count)
{
unsigned long offset;
bool ret = true;
if (pthread_mutex_lock(&blk_device.mutex) < 0)
die("pthread_mutex_lock");
offset = port - IOPORT_VIRTIO_BLK;
@@ -201,10 +221,15 @@ static bool virtio_blk_pci_io_out(struct kvm *self, uint16_t port, void *data, i
case VIRTIO_MSI_QUEUE_VECTOR:
break;
default:
return false;
ret = false;
goto out_unlock;
};
return true;
out_unlock:
if (pthread_mutex_unlock(&blk_device.mutex) < 0)
die("pthread_mutex_unlock");
return ret;
}
static struct ioport_operations virtio_blk_io_ops = {