[Qemu-devel] [PATCH RFC 02/11] virtio: add support for 64 bit features.

[Cornelia Huck]

From: Rusty Russell <address@hidden>

Change the u32 to a u64, and make sure to use 1ULL everywhere!

Cc: Brian Swetland <address@hidden>
Cc: Christian Borntraeger <address@hidden>
[Thomas Huth: fix up virtio-ccw get_features]
Signed-off-by: Rusty Russell <address@hidden>
Signed-off-by: Cornelia Huck <address@hidden>
Acked-by: Pawel Moll <address@hidden>
Acked-by: Ohad Ben-Cohen <address@hidden>
---
 drivers/char/virtio_console.c          |    2 +-
 drivers/lguest/lguest_device.c         |   10 +++++-----
 drivers/remoteproc/remoteproc_virtio.c |    5 ++++-
 drivers/s390/kvm/kvm_virtio.c          |   10 +++++-----
 drivers/s390/kvm/virtio_ccw.c          |   29 ++++++++++++++++++++++++-----
 drivers/virtio/virtio.c                |   12 ++++++------
 drivers/virtio/virtio_mmio.c           |   14 +++++++++-----
 drivers/virtio/virtio_pci.c            |    5 ++---
 drivers/virtio/virtio_ring.c           |    2 +-
 include/linux/virtio.h                 |    2 +-
 include/linux/virtio_config.h          |    8 ++++----
 tools/virtio/linux/virtio.h            |    2 +-
 tools/virtio/linux/virtio_config.h     |    2 +-
 13 files changed, 64 insertions(+), 39 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index c4a437e..f9c6288 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -355,7 +355,7 @@ static inline bool use_multiport(struct ports_device 
*portdev)
         */
        if (!portdev->vdev)
                return 0;
-       return portdev->vdev->features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+       return portdev->vdev->features & (1ULL << VIRTIO_CONSOLE_F_MULTIPORT);
 }
 
 static DEFINE_SPINLOCK(dma_bufs_lock);
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index c831c47..4d29bcd 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -94,17 +94,17 @@ static unsigned desc_size(const struct lguest_device_desc 
*desc)
 }
 
 /* This gets the device's feature bits. */
-static u32 lg_get_features(struct virtio_device *vdev)
+static u64 lg_get_features(struct virtio_device *vdev)
 {
        unsigned int i;
-       u32 features = 0;
+       u64 features = 0;
        struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
        u8 *in_features = lg_features(desc);
 
        /* We do this the slow but generic way. */
-       for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+       for (i = 0; i < min(desc->feature_len * 8, 64); i++)
                if (in_features[i / 8] & (1 << (i % 8)))
-                       features |= (1 << i);
+                       features |= (1ULL << i);
 
        return features;
 }
@@ -144,7 +144,7 @@ static void lg_finalize_features(struct virtio_device *vdev)
        memset(out_features, 0, desc->feature_len);
        bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
        for (i = 0; i < bits; i++) {
-               if (vdev->features & (1 << i))
+               if (vdev->features & (1ULL << i))
                        out_features[i / 8] |= (1 << (i % 8));
        }
 
diff --git a/drivers/remoteproc/remoteproc_virtio.c 
b/drivers/remoteproc/remoteproc_virtio.c
index dafaf38..627737e 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -207,7 +207,7 @@ static void rproc_virtio_reset(struct virtio_device *vdev)
 }
 
 /* provide the vdev features as retrieved from the firmware */
-static u32 rproc_virtio_get_features(struct virtio_device *vdev)
+static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 {
        struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
        struct fw_rsc_vdev *rsc;
@@ -227,6 +227,9 @@ static void rproc_virtio_finalize_features(struct 
virtio_device *vdev)
        /* Give virtio_ring a chance to accept features */
        vring_transport_features(vdev);
 
+       /* Make sure we don't have any features > 32 bits! */
+       BUG_ON((u32)vdev->features != vdev->features);
+
        /*
         * Remember the finalized features of our vdev, and provide it
         * to the remote processor once it is powered on.
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index d747ca4..6d4cbea 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -80,16 +80,16 @@ static unsigned desc_size(const struct kvm_device_desc 
*desc)
 }
 
 /* This gets the device's feature bits. */
-static u32 kvm_get_features(struct virtio_device *vdev)
+static u64 kvm_get_features(struct virtio_device *vdev)
 {
        unsigned int i;
-       u32 features = 0;
+       u64 features = 0;
        struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
        u8 *in_features = kvm_vq_features(desc);
 
-       for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+       for (i = 0; i < min(desc->feature_len * 8, 64); i++)
                if (in_features[i / 8] & (1 << (i % 8)))
-                       features |= (1 << i);
+                       features |= (1ULL << i);
        return features;
 }
 
@@ -106,7 +106,7 @@ static void kvm_finalize_features(struct virtio_device 
*vdev)
        memset(out_features, 0, desc->feature_len);
        bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
        for (i = 0; i < bits; i++) {
-               if (vdev->features & (1 << i))
+               if (vdev->features & (1ULL << i))
                        out_features[i / 8] |= (1 << (i % 8));
        }
 }
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index c5acd19..4173b59 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -660,11 +660,12 @@ static void virtio_ccw_reset(struct virtio_device *vdev)
        kfree(ccw);
 }
 
-static u32 virtio_ccw_get_features(struct virtio_device *vdev)
+static u64 virtio_ccw_get_features(struct virtio_device *vdev)
 {
        struct virtio_ccw_device *vcdev = to_vc_device(vdev);
        struct virtio_feature_desc *features;
-       int ret, rc;
+       int ret;
+       u64 rc;
        struct ccw1 *ccw;
 
        ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -677,7 +678,6 @@ static u32 virtio_ccw_get_features(struct virtio_device 
*vdev)
                goto out_free;
        }
        /* Read the feature bits from the host. */
-       /* TODO: Features > 32 bits */
        features->index = 0;
        ccw->cmd_code = CCW_CMD_READ_FEAT;
        ccw->flags = 0;
@@ -691,6 +691,16 @@ static u32 virtio_ccw_get_features(struct virtio_device 
*vdev)
 
        rc = le32_to_cpu(features->features);
 
+       /* Read second half feature bits from the host. */
+       features->index = 1;
+       ccw->cmd_code = CCW_CMD_READ_FEAT;
+       ccw->flags = 0;
+       ccw->count = sizeof(*features);
+       ccw->cda = (__u32)(unsigned long)features;
+       ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
+       if (ret == 0)
+               rc |= (u64)le32_to_cpu(features->features) << 32;
+
 out_free:
        kfree(features);
        kfree(ccw);
@@ -715,8 +725,17 @@ static void virtio_ccw_finalize_features(struct 
virtio_device *vdev)
        vring_transport_features(vdev);
 
        features->index = 0;
-       features->features = cpu_to_le32(vdev->features);
-       /* Write the feature bits to the host. */
+       features->features = cpu_to_le32((u32)vdev->features);
+       /* Write the first half of the feature bits to the host. */
+       ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+       ccw->flags = 0;
+       ccw->count = sizeof(*features);
+       ccw->cda = (__u32)(unsigned long)features;
+       ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
+       features->index = 1;
+       features->features = cpu_to_le32(vdev->features >> 32);
+       /* Write the second half of the feature bits to the host. */
        ccw->cmd_code = CCW_CMD_WRITE_FEAT;
        ccw->flags = 0;
        ccw->count = sizeof(*features);
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 601efc3..cfd5d00 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -122,7 +122,7 @@ static int virtio_dev_probe(struct device *_d)
        int err, i;
        struct virtio_device *dev = dev_to_virtio(_d);
        struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
-       u32 device_features;
+       u64 device_features;
 
        /* We have a driver! */
        add_status(dev, VIRTIO_CONFIG_S_DRIVER);
@@ -134,15 +134,15 @@ static int virtio_dev_probe(struct device *_d)
        dev->features = 0;
        for (i = 0; i < drv->feature_table_size; i++) {
                unsigned int f = drv->feature_table[i];
-               BUG_ON(f >= 32);
-               if (device_features & (1 << f))
-                       dev->features |= (1 << f);
+               BUG_ON(f >= 64);
+               if (device_features & (1ULL << f))
+                       dev->features |= (1ULL << f);
        }
 
        /* Transport features always preserved to pass to finalize_features. */
        for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
-               if (device_features & (1 << i))
-                       dev->features |= (1 << i);
+               if (device_features & (1ULL << i))
+                       dev->features |= (1ULL << i);
 
        dev->config->finalize_features(dev);
 
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index de47734..17f8367 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -142,14 +142,16 @@ struct virtio_mmio_vq_info {
 
 /* Configuration interface */
 
-static u32 vm_get_features(struct virtio_device *vdev)
+static u64 vm_get_features(struct virtio_device *vdev)
 {
        struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+       u64 features;
 
-       /* TODO: Features > 32 bits */
        writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
-
-       return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
+       features = readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
+       writel(1, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
+       features |= ((u64)readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES) << 
32);
+       return features;
 }
 
 static void vm_finalize_features(struct virtio_device *vdev)
@@ -160,7 +162,9 @@ static void vm_finalize_features(struct virtio_device *vdev)
        vring_transport_features(vdev);
 
        writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
-       writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
+       writel((u32)vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
+       writel(1, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
+       writel(vdev->features >> 32, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 }
 
 static void vm_get(struct virtio_device *vdev, unsigned offset,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index bb8d0ab..3b272d9 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -105,12 +105,11 @@ static struct virtio_pci_device *to_vp_device(struct 
virtio_device *vdev)
 }
 
 /* virtio config->get_features() implementation */
-static u32 vp_get_features(struct virtio_device *vdev)
+static u64 vp_get_features(struct virtio_device *vdev)
 {
        struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
-       /* When someone needs more than 32 feature bits, we'll need to
-        * steal a bit to indicate that the rest are somewhere else. */
+       /* We only support 32 feature bits. */
        return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
 }
 
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 94eb463..1cfb5ba 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -835,7 +835,7 @@ void vring_transport_features(struct virtio_device *vdev)
                        break;
                default:
                        /* We don't understand this bit. */
-                       vdev->features &= ~(1 << i);
+                       vdev->features &= ~(1ULL << i);
                }
        }
 }
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 4b8380a..a24b41f 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -93,7 +93,7 @@ struct virtio_device {
        const struct virtio_config_ops *config;
        const struct vringh_config_ops *vringh_config;
        struct list_head vqs;
-       u32 features;
+       u64 features;
        void *priv;
 };
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index d300c02..a0e16d8 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -66,7 +66,7 @@ struct virtio_config_ops {
                        vq_callback_t *callbacks[],
                        const char *names[]);
        void (*del_vqs)(struct virtio_device *);
-       u32 (*get_features)(struct virtio_device *vdev);
+       u64 (*get_features)(struct virtio_device *vdev);
        void (*finalize_features)(struct virtio_device *vdev);
        const char *(*bus_name)(struct virtio_device *vdev);
        int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
@@ -86,14 +86,14 @@ static inline bool virtio_has_feature(const struct 
virtio_device *vdev,
 {
        /* Did you forget to fix assumptions on max features? */
        if (__builtin_constant_p(fbit))
-               BUILD_BUG_ON(fbit >= 32);
+               BUILD_BUG_ON(fbit >= 64);
        else
-               BUG_ON(fbit >= 32);
+               BUG_ON(fbit >= 64);
 
        if (fbit < VIRTIO_TRANSPORT_F_START)
                virtio_check_driver_offered_feature(vdev, fbit);
 
-       return vdev->features & (1 << fbit);
+       return vdev->features & (1ULL << fbit);
 }
 
 static inline
diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
index 72bff70..8eb6421 100644
--- a/tools/virtio/linux/virtio.h
+++ b/tools/virtio/linux/virtio.h
@@ -10,7 +10,7 @@
 
 struct virtio_device {
        void *dev;
-       u32 features;
+       u64 features;
 };
 
 struct virtqueue {
diff --git a/tools/virtio/linux/virtio_config.h 
b/tools/virtio/linux/virtio_config.h
index 1f1636b..a254c2b 100644
--- a/tools/virtio/linux/virtio_config.h
+++ b/tools/virtio/linux/virtio_config.h
@@ -2,5 +2,5 @@
 #define VIRTIO_TRANSPORT_F_END         32
 
 #define virtio_has_feature(dev, feature) \
-       ((dev)->features & (1 << feature))
+       ((dev)->features & (1ULL << feature))
 
-- 
1.7.9.5