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vhost: switch to arrays of feature bits

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The current interface where caller has to know in which 64 bit chunk
each bit is, is inelegant and fragile.
Let's simply use arrays of bits.
By using unroll macros text size grows only slightly.

Message-ID: <637e182e139980e5930d50b928ba5ac072d628a9.1764225384.git.mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Michael S. Tsirkin
2025-11-13 17:42:05 -05:00
parent 350a840110
commit dfe44d177a
5 changed files with 61 additions and 25 deletions
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19
drivers/vhost/net.c
View File

@@ -69,15 +69,15 @@ MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)
static const u64 vhost_net_features[VIRTIO_FEATURES_U64S] = {
VHOST_FEATURES |
(1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
(1ULL << VIRTIO_NET_F_MRG_RXBUF) |
(1ULL << VIRTIO_F_ACCESS_PLATFORM) |
(1ULL << VIRTIO_F_RING_RESET) |
(1ULL << VIRTIO_F_IN_ORDER),
VIRTIO_BIT(VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO) |
VIRTIO_BIT(VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO),
static const int vhost_net_bits[] = {
VHOST_FEATURES,
VHOST_NET_F_VIRTIO_NET_HDR,
VIRTIO_NET_F_MRG_RXBUF,
VIRTIO_F_ACCESS_PLATFORM,
VIRTIO_F_RING_RESET,
VIRTIO_F_IN_ORDER,
VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO,
VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO
};
enum {
@@ -1720,6 +1720,7 @@ out:
static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
unsigned long arg)
{
const DEFINE_VHOST_FEATURES_ARRAY(vhost_net_features, vhost_net_bits);
u64 all_features[VIRTIO_FEATURES_U64S];
struct vhost_net *n = f->private_data;
void __user *argp = (void __user *)arg;

9
drivers/vhost/scsi.c
View File

@@ -197,11 +197,14 @@ enum {
};
/* Note: can't set VIRTIO_F_VERSION_1 yet, since that implies ANY_LAYOUT. */
enum {
VHOST_SCSI_FEATURES = VHOST_FEATURES | (1ULL << VIRTIO_SCSI_F_HOTPLUG) |
(1ULL << VIRTIO_SCSI_F_T10_PI)
static const int vhost_scsi_bits[] = {
VHOST_FEATURES,
VIRTIO_SCSI_F_HOTPLUG,
VIRTIO_SCSI_F_T10_PI
};
#define VHOST_SCSI_FEATURES VHOST_FEATURES_U64(vhost_scsi_bits, 0)
#define VHOST_SCSI_MAX_TARGET 256
#define VHOST_SCSI_MAX_IO_VQ 1024
#define VHOST_SCSI_MAX_EVENT 128

6
drivers/vhost/test.c
View File

@@ -28,7 +28,11 @@
*/
#define VHOST_TEST_PKT_WEIGHT 256
#define VHOST_TEST_FEATURES VHOST_FEATURES
static const int vhost_test_bits[] = {
VHOST_FEATURES
};
#define VHOST_TEST_FEATURES VHOST_FEATURES_U64(vhost_test_bits, 0)
enum {
VHOST_TEST_VQ = 0,

42
drivers/vhost/vhost.h
View File

@@ -14,6 +14,7 @@
#include <linux/atomic.h>
#include <linux/vhost_iotlb.h>
#include <linux/irqbypass.h>
#include <linux/unroll.h>
struct vhost_work;
struct vhost_task;
@@ -279,14 +280,39 @@ void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
eventfd_signal((vq)->error_ctx);\
} while (0)
enum {
VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
(1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
(1ULL << VIRTIO_RING_F_EVENT_IDX) |
(1ULL << VHOST_F_LOG_ALL) |
(1ULL << VIRTIO_F_ANY_LAYOUT) |
(1ULL << VIRTIO_F_VERSION_1)
};
#define VHOST_FEATURES \
VIRTIO_F_NOTIFY_ON_EMPTY, \
VIRTIO_RING_F_INDIRECT_DESC, \
VIRTIO_RING_F_EVENT_IDX, \
VHOST_F_LOG_ALL, \
VIRTIO_F_ANY_LAYOUT, \
VIRTIO_F_VERSION_1
static inline u64 vhost_features_u64(const int *features, int size, int idx)
{
u64 res = 0;
unrolled_count(VIRTIO_FEATURES_BITS)
for (int i = 0; i < size; ++i) {
int bit = features[i];
if (virtio_features_chk_bit(bit) && VIRTIO_U64(bit) == idx)
res |= VIRTIO_BIT(bit);
}
return res;
}
#define VHOST_FEATURES_U64(features, idx) \
vhost_features_u64(features, ARRAY_SIZE(features), idx)
#define DEFINE_VHOST_FEATURES_ARRAY_ENTRY(idx, features) \
[idx] = VHOST_FEATURES_U64(features, idx),
#define DEFINE_VHOST_FEATURES_ARRAY(array, features) \
u64 array[VIRTIO_FEATURES_U64S] = { \
UNROLL(VIRTIO_FEATURES_U64S, \
DEFINE_VHOST_FEATURES_ARRAY_ENTRY, features) \
}
/**
* vhost_vq_set_backend - Set backend.

10
drivers/vhost/vsock.c
View File

@@ -29,12 +29,14 @@
*/
#define VHOST_VSOCK_PKT_WEIGHT 256
enum {
VHOST_VSOCK_FEATURES = VHOST_FEATURES |
(1ULL << VIRTIO_F_ACCESS_PLATFORM) |
(1ULL << VIRTIO_VSOCK_F_SEQPACKET)
static const int vhost_vsock_bits[] = {
VHOST_FEATURES,
VIRTIO_F_ACCESS_PLATFORM,
VIRTIO_VSOCK_F_SEQPACKET
};
#define VHOST_VSOCK_FEATURES VHOST_FEATURES_U64(vhost_vsock_bits, 0)
enum {
VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
};