[05/19] virtio: Implement get_shm_region for MMIO transport
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Message ID 20190821175720.25901-6-vgoyal@redhat.com
State New
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Series
  • virtio-fs: Enable DAX support
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Commit Message

Vivek Goyal Aug. 21, 2019, 5:57 p.m. UTC
From: Sebastien Boeuf <sebastien.boeuf@intel.com>

On MMIO a new set of registers is defined for finding SHM
regions.  Add their definitions and use them to find the region.

Cc: kvm@vger.kernel.org
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 drivers/virtio/virtio_mmio.c     | 32 ++++++++++++++++++++++++++++++++
 include/uapi/linux/virtio_mmio.h | 11 +++++++++++
 2 files changed, 43 insertions(+)

Comments

Cornelia Huck Aug. 27, 2019, 8:39 a.m. UTC | #1
On Wed, 21 Aug 2019 13:57:06 -0400
Vivek Goyal <vgoyal@redhat.com> wrote:

> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> 
> On MMIO a new set of registers is defined for finding SHM
> regions.  Add their definitions and use them to find the region.
> 
> Cc: kvm@vger.kernel.org
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> ---
>  drivers/virtio/virtio_mmio.c     | 32 ++++++++++++++++++++++++++++++++
>  include/uapi/linux/virtio_mmio.h | 11 +++++++++++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index e09edb5c5e06..5c07985c8cb8 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -500,6 +500,37 @@ static const char *vm_bus_name(struct virtio_device *vdev)
>  	return vm_dev->pdev->name;
>  }
>  
> +static bool vm_get_shm_region(struct virtio_device *vdev,
> +			      struct virtio_shm_region *region, u8 id)
> +{
> +	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
> +	u64 len, addr;
> +
> +	/* Select the region we're interested in */
> +	writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
> +
> +	/* Read the region size */
> +	len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
> +	len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
> +
> +	region->len = len;
> +
> +	/* Check if region length is -1. If that's the case, the shared memory
> +	 * region does not exist and there is no need to proceed further.
> +	 */
> +	if (len == ~(u64)0) {
> +		return false;
> +	}

I think the curly braces should be dropped here.

> +
> +	/* Read the region base address */
> +	addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
> +	addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
> +
> +	region->addr = addr;
> +
> +	return true;
> +}
> +
>  static const struct virtio_config_ops virtio_mmio_config_ops = {
>  	.get		= vm_get,
>  	.set		= vm_set,

Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Vivek Goyal Aug. 27, 2019, 11:54 a.m. UTC | #2
On Tue, Aug 27, 2019 at 10:39:43AM +0200, Cornelia Huck wrote:
> On Wed, 21 Aug 2019 13:57:06 -0400
> Vivek Goyal <vgoyal@redhat.com> wrote:
> 
> > From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> > 
> > On MMIO a new set of registers is defined for finding SHM
> > regions.  Add their definitions and use them to find the region.
> > 
> > Cc: kvm@vger.kernel.org
> > Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> > ---
> >  drivers/virtio/virtio_mmio.c     | 32 ++++++++++++++++++++++++++++++++
> >  include/uapi/linux/virtio_mmio.h | 11 +++++++++++
> >  2 files changed, 43 insertions(+)
> > 
> > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > index e09edb5c5e06..5c07985c8cb8 100644
> > --- a/drivers/virtio/virtio_mmio.c
> > +++ b/drivers/virtio/virtio_mmio.c
> > @@ -500,6 +500,37 @@ static const char *vm_bus_name(struct virtio_device *vdev)
> >  	return vm_dev->pdev->name;
> >  }
> >  
> > +static bool vm_get_shm_region(struct virtio_device *vdev,
> > +			      struct virtio_shm_region *region, u8 id)
> > +{
> > +	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
> > +	u64 len, addr;
> > +
> > +	/* Select the region we're interested in */
> > +	writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
> > +
> > +	/* Read the region size */
> > +	len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
> > +	len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
> > +
> > +	region->len = len;
> > +
> > +	/* Check if region length is -1. If that's the case, the shared memory
> > +	 * region does not exist and there is no need to proceed further.
> > +	 */
> > +	if (len == ~(u64)0) {
> > +		return false;
> > +	}
> 
> I think the curly braces should be dropped here.

Will do.

Thanks
Vivek

Patch
diff mbox series

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index e09edb5c5e06..5c07985c8cb8 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -500,6 +500,37 @@  static const char *vm_bus_name(struct virtio_device *vdev)
 	return vm_dev->pdev->name;
 }
 
+static bool vm_get_shm_region(struct virtio_device *vdev,
+			      struct virtio_shm_region *region, u8 id)
+{
+	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+	u64 len, addr;
+
+	/* Select the region we're interested in */
+	writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
+
+	/* Read the region size */
+	len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
+	len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
+
+	region->len = len;
+
+	/* Check if region length is -1. If that's the case, the shared memory
+	 * region does not exist and there is no need to proceed further.
+	 */
+	if (len == ~(u64)0) {
+		return false;
+	}
+
+	/* Read the region base address */
+	addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
+	addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
+
+	region->addr = addr;
+
+	return true;
+}
+
 static const struct virtio_config_ops virtio_mmio_config_ops = {
 	.get		= vm_get,
 	.set		= vm_set,
@@ -512,6 +543,7 @@  static const struct virtio_config_ops virtio_mmio_config_ops = {
 	.get_features	= vm_get_features,
 	.finalize_features = vm_finalize_features,
 	.bus_name	= vm_bus_name,
+	.get_shm_region = vm_get_shm_region,
 };
 
 
diff --git a/include/uapi/linux/virtio_mmio.h b/include/uapi/linux/virtio_mmio.h
index c4b09689ab64..0650f91bea6c 100644
--- a/include/uapi/linux/virtio_mmio.h
+++ b/include/uapi/linux/virtio_mmio.h
@@ -122,6 +122,17 @@ 
 #define VIRTIO_MMIO_QUEUE_USED_LOW	0x0a0
 #define VIRTIO_MMIO_QUEUE_USED_HIGH	0x0a4
 
+/* Shared memory region id */
+#define VIRTIO_MMIO_SHM_SEL             0x0ac
+
+/* Shared memory region length, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_LEN_LOW         0x0b0
+#define VIRTIO_MMIO_SHM_LEN_HIGH        0x0b4
+
+/* Shared memory region base address, 64 bits in two halves */
+#define VIRTIO_MMIO_SHM_BASE_LOW        0x0b8
+#define VIRTIO_MMIO_SHM_BASE_HIGH       0x0bc
+
 /* Configuration atomicity value */
 #define VIRTIO_MMIO_CONFIG_GENERATION	0x0fc