From: Si-Wei Liu <si-wei.liu@oracle.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org, elic@nvidia.com,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 4/7] virtio: VIRTIO_DEVICE_F_MASK for all per-device features
Date: Thu, 2 Feb 2023 14:00:59 -0800 [thread overview]
Message-ID: <57fe17e4-b60a-49aa-4661-bf88b0753953@oracle.com> (raw)
In-Reply-To: <20230202122851-mutt-send-email-mst@kernel.org>
On 2/2/2023 9:29 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 31, 2023 at 03:22:22PM -0800, Si-Wei Liu wrote:
>> Introduce VIRTIO_DEVICE_F_MASK bitmask used for identification
>> of per-device features. Feature bits VIRTIO_TRANSPORT_F_START
>> through VIRTIO_TRANSPORT_F_END are reserved for transport
>> features hence are not counted as per-device features against
>> the 64bit feature space.
>>
>> Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
>> ---
>> include/uapi/linux/virtio_config.h | 8 ++++++++
>> 1 file changed, 8 insertions(+)
> Pls don't add this in uapi, people tend to depend on this and then
> things fail when we extend virtio. For example this won't work with >64
> feature bits.
Good point. Then keep this macro private to vdpa.c for now?
-Siwei
>
>> diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
>> index 3c05162..3bdc7ed 100644
>> --- a/include/uapi/linux/virtio_config.h
>> +++ b/include/uapi/linux/virtio_config.h
>> @@ -54,6 +54,14 @@
>> #define VIRTIO_TRANSPORT_F_START 28
>> #define VIRTIO_TRANSPORT_F_END 41
>>
>> +/*
>> + * Bitmask for all per-device features: feature bits VIRTIO_TRANSPORT_F_START
>> + * through VIRTIO_TRANSPORT_F_END are unset, i.e. 0xfffffc000fffffff for
>> + * all 64bit features
>> + */
>> +#define VIRTIO_DEVICE_F_MASK (~0ULL << (VIRTIO_TRANSPORT_F_END + 1) | \
>> + ((1ULL << VIRTIO_TRANSPORT_F_START) - 1))
>> +
>> #ifndef VIRTIO_CONFIG_NO_LEGACY
>> /* Do we get callbacks when the ring is completely used, even if we've
>> * suppressed them? */
>> --
>> 1.8.3.1
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next prev parent reply other threads:[~2023-02-02 22:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-31 23:22 [PATCH v2 0/7] features provisioning fixes and mlx5_vdpa support Si-Wei Liu
2023-01-31 23:22 ` [PATCH v2 1/7] vdpa: fix improper error message when adding vdpa dev Si-Wei Liu
2023-02-02 4:45 ` Parav Pandit via Virtualization
2023-01-31 23:22 ` [PATCH v2 2/7] vdpa: conditionally read STATUS in config space Si-Wei Liu
2023-02-02 4:58 ` Parav Pandit via Virtualization
2023-01-31 23:22 ` [PATCH v2 3/7] vdpa: validate provisioned device features against specified attribute Si-Wei Liu
2023-02-02 5:05 ` Parav Pandit via Virtualization
2023-02-02 21:58 ` Si-Wei Liu
2023-02-02 22:01 ` Parav Pandit via Virtualization
2023-01-31 23:22 ` [PATCH v2 4/7] virtio: VIRTIO_DEVICE_F_MASK for all per-device features Si-Wei Liu
2023-02-02 17:29 ` Michael S. Tsirkin
2023-02-02 22:00 ` Si-Wei Liu [this message]
2023-01-31 23:22 ` [PATCH v2 5/7] vdpa: validate device feature provisioning against supported class Si-Wei Liu
2023-02-03 8:09 ` Michael S. Tsirkin
2023-02-03 19:32 ` Si-Wei Liu
2023-01-31 23:22 ` [PATCH v2 6/7] vdpa/mlx5: conditionally show MTU and STATUS in config space Si-Wei Liu
[not found] ` <bad92641-e10e-cb06-179d-2f4bc11c721d@nvidia.com>
2023-02-02 22:18 ` Si-Wei Liu
2023-02-03 8:14 ` Michael S. Tsirkin
2023-02-03 19:37 ` Si-Wei Liu
2023-01-31 23:22 ` [PATCH v2 7/7] vdpa/mlx5: support device features provisioning Si-Wei Liu
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