From: Laurent Vivier <lvivier@redhat.com>
To: Stefano Brivio <sbrivio@redhat.com>
Cc: passt-dev@passt.top
Subject: Re: [PATCH v4 2/4] vhost-user: introduce virtio API
Date: Thu, 12 Sep 2024 13:23:58 +0200 [thread overview]
Message-ID: <e08f5076-7ff4-490e-bae4-a90edceaa3c7@redhat.com> (raw)
In-Reply-To: <20240910174731.3c4db56f@elisabeth>
On 10/09/2024 17:47, Stefano Brivio wrote:
>> +
>> +/**
>> + * virtqueue_read_indirect_desc() - Copy virtio ring descriptors from guest
>> + * memory
>> + * @dev: Vhost-user device
>> + * @desc: Destination address to copy the descriptors to
>> + * @addr: Guest memory address to copy from
>> + * @len: Length of memory to copy
>> + *
>> + * Return: -1 if there is an error, 0 otherwise
>> + */
>> +static int virtqueue_read_indirect_desc(struct vu_dev *dev, struct vring_desc *desc,
>> + uint64_t addr, size_t len)
>> +{
>> + uint64_t read_len;
>> +
>> + if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc)))
>> + return -1;
>> +
>> + if (len == 0)
>> + return -1;
>> +
>> + while (len) {
>> + const struct vring_desc *orig_desc;
>> +
>> + read_len = len;
>> + orig_desc = vu_gpa_to_va(dev, &read_len, addr);
> In case you missed this in my review of v3 (I'm not sure if it's a
> valid concern):
>
> --
> Should we also return if read_len < sizeof(struct vring_desc) after
> this call? Can that ever happen, if we pick a particular value of addr
> so that it's almost at the end of a region?
> --
In fact, read_len can be < sizeof(struct vring_desc) after this call but if orig_desc !=
NULL it means we can continue in another region to continue to fill the structure.
If there is not enough memory to fill "len" bytes it exits with -1.
Thanks,
Laurent
next prev parent reply other threads:[~2024-09-12 11:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-06 16:04 [PATCH v4 0/4] Add vhost-user support to passt. (part 3) Laurent Vivier
2024-09-06 16:04 ` [PATCH v4 1/4] packet: replace struct desc by struct iovec Laurent Vivier
2024-09-06 16:04 ` [PATCH v4 2/4] vhost-user: introduce virtio API Laurent Vivier
2024-09-10 15:47 ` Stefano Brivio
2024-09-12 11:23 ` Laurent Vivier [this message]
2024-09-12 13:36 ` Stefano Brivio
2024-09-12 14:03 ` Laurent Vivier
2024-09-12 14:08 ` Stefano Brivio
2024-09-06 16:04 ` [PATCH v4 3/4] vhost-user: introduce vhost-user API Laurent Vivier
2024-09-10 15:47 ` Stefano Brivio
2024-09-12 12:41 ` Laurent Vivier
2024-09-12 13:40 ` Stefano Brivio
2024-09-06 16:04 ` [PATCH v4 4/4] vhost-user: add vhost-user Laurent Vivier
2024-09-10 15:47 ` Stefano Brivio
2024-09-12 14:05 ` Laurent Vivier
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e08f5076-7ff4-490e-bae4-a90edceaa3c7@redhat.com \
--to=lvivier@redhat.com \
--cc=passt-dev@passt.top \
--cc=sbrivio@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://passt.top/passt
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for IMAP folder(s).