From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "julien@xen.org" <julien@xen.org>,
"sstabellini@kernel.org" <sstabellini@kernel.org>,
Oleksandr Tyshchenko <Oleksandr_Tyshchenko@epam.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Artem Mygaiev <Artem_Mygaiev@epam.com>,
"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
"george.dunlap@citrix.com" <george.dunlap@citrix.com>,
"paul@xen.org" <paul@xen.org>,
Bertrand Marquis <bertrand.marquis@arm.com>,
Rahul Singh <rahul.singh@arm.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"roger.pau@citrix.com" <roger.pau@citrix.com>,
Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
Subject: Re: [PATCH v6 05/13] vpci: add hooks for PCI device assign/de-assign
Date: Tue, 8 Feb 2022 11:25:50 +0000 [thread overview]
Message-ID: <a0015951-6eff-38a8-a9f0-bdbc8bd51940@epam.com> (raw)
In-Reply-To: <cf584e13-f257-9355-50fa-c35e8fc8cf5e@suse.com>
On 08.02.22 13:00, Jan Beulich wrote:
> On 08.02.2022 11:52, Oleksandr Andrushchenko wrote:
>> This smells like we first need to fix the existing code, so
>> pdev->domain is not assigned by specific IOMMU implementations,
>> but instead controlled by the code which relies on that, assign_device.
> Feel free to come up with proposals how to cleanly do so. Moving the
> assignment to pdev->domain may even be possible now, but if you go
> back you may find that the code was quite different earlier on.
I do understand that as the code evolves new use cases bring
new issues.
>
>> I can have something like:
>>
>> diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
>> index 88836aab6baf..cc7790709a50 100644
>> --- a/xen/drivers/passthrough/pci.c
>> +++ b/xen/drivers/passthrough/pci.c
>> @@ -1475,6 +1475,7 @@ static int device_assigned(u16 seg, u8 bus, u8 devfn)
>> static int assign_device(struct domain *d, u16 seg, u8 bus, u8 devfn, u32 flag)
>> {
>> const struct domain_iommu *hd = dom_iommu(d);
>> + struct domain *old_owner;
>> struct pci_dev *pdev;
>> int rc = 0;
>>
>> @@ -1490,6 +1491,9 @@ static int assign_device(struct domain *d, u16 seg, u8 bus, u8 devfn, u32 flag)
>> ASSERT(pdev && (pdev->domain == hardware_domain ||
>> pdev->domain == dom_io));
>>
>> + /* We need to restore the old owner in case of an error. */
>> + old_owner = pdev->domain;
>> +
>> vpci_deassign_device(pdev->domain, pdev);
>>
>> rc = pdev_msix_assign(d, pdev);
>> @@ -1515,8 +1519,12 @@ static int assign_device(struct domain *d, u16 seg, u8 bus, u8 devfn, u32 flag)
>>
>> done:
>> if ( rc )
>> + {
>> printk(XENLOG_G_WARNING "%pd: assign (%pp) failed (%d)\n",
>> d, &PCI_SBDF3(seg, bus, devfn), rc);
>> + /* We failed to assign, so restore the previous owner. */
>> + pdev->domain = old_owner;
>> + }
>> /* The device is assigned to dom_io so mark it as quarantined */
>> else if ( d == dom_io )
>> pdev->quarantine = true;
>>
>> But I do not think this belongs to this patch
> Indeed. Plus I'm sure you understand that it's not that simple. Assigning
> to pdev->domain is only the last step of assignment. Restoring the original
> owner would entail putting in place the original IOMMU table entries as
> well, which in turn can fail. Hence why you'll find a number of uses of
> domain_crash() in places where rolling back is far from easy.
So, why don't we just rely on the toolstack to do the roll back then?
This way we won't add new domain_crash() calls.
I do understand though that we may live Xen in a wrong state though.
So, do you think it is possible if we just call deassign_device from
assign_device on the error path? This is just like I do in vpci_assign_device:
I call vpci_deassign_device if the former fails.
> Jan
>
Thank you,
Oleksandr
next prev parent reply other threads:[~2022-02-08 11:26 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 6:34 [PATCH v6 00/13] PCI devices passthrough on Arm, part 3 Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 01/13] xen/pci: arm: add stub for is_memory_hole Oleksandr Andrushchenko
2022-02-04 8:51 ` Julien Grall
2022-02-04 9:01 ` Oleksandr Andrushchenko
2022-02-04 9:41 ` Julien Grall
2022-02-04 9:47 ` Oleksandr Andrushchenko
2022-02-04 9:57 ` Julien Grall
2022-02-04 10:35 ` Oleksandr Andrushchenko
2022-02-04 11:00 ` Julien Grall
2022-02-04 11:25 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 02/13] rangeset: add RANGESETF_no_print flag Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 03/13] vpci: move lock outside of struct vpci Oleksandr Andrushchenko
2022-02-04 7:52 ` Jan Beulich
2022-02-04 8:13 ` Oleksandr Andrushchenko
2022-02-04 8:36 ` Jan Beulich
2022-02-04 8:58 ` Oleksandr Andrushchenko
2022-02-04 9:15 ` Jan Beulich
2022-02-04 10:12 ` Oleksandr Andrushchenko
2022-02-04 10:49 ` Jan Beulich
2022-02-04 11:13 ` Roger Pau Monné
2022-02-04 11:37 ` Jan Beulich
2022-02-04 12:37 ` Oleksandr Andrushchenko
2022-02-04 12:47 ` Jan Beulich
2022-02-04 12:53 ` Oleksandr Andrushchenko
2022-02-04 13:03 ` Jan Beulich
2022-02-04 13:06 ` Roger Pau Monné
2022-02-04 14:43 ` Oleksandr Andrushchenko
2022-02-04 14:57 ` Roger Pau Monné
2022-02-07 11:08 ` Oleksandr Andrushchenko
2022-02-07 12:34 ` Jan Beulich
2022-02-07 12:57 ` Oleksandr Andrushchenko
2022-02-07 13:02 ` Jan Beulich
2022-02-07 12:46 ` Roger Pau Monné
2022-02-07 13:53 ` Oleksandr Andrushchenko
2022-02-07 14:11 ` Jan Beulich
2022-02-07 14:27 ` Roger Pau Monné
2022-02-07 14:33 ` Jan Beulich
2022-02-07 14:35 ` Oleksandr Andrushchenko
2022-02-07 15:11 ` Oleksandr Andrushchenko
2022-02-07 15:26 ` Jan Beulich
2022-02-07 16:07 ` Oleksandr Andrushchenko
2022-02-07 16:15 ` Jan Beulich
2022-02-07 16:21 ` Oleksandr Andrushchenko
2022-02-07 16:37 ` Jan Beulich
2022-02-07 16:44 ` Oleksandr Andrushchenko
2022-02-08 7:35 ` Oleksandr Andrushchenko
2022-02-08 8:57 ` Jan Beulich
2022-02-08 9:03 ` Oleksandr Andrushchenko
2022-02-08 10:50 ` Roger Pau Monné
2022-02-08 11:13 ` Oleksandr Andrushchenko
2022-02-08 13:38 ` Roger Pau Monné
2022-02-08 13:52 ` Oleksandr Andrushchenko
2022-02-08 8:53 ` Jan Beulich
2022-02-08 9:00 ` Oleksandr Andrushchenko
2022-02-08 10:11 ` Roger Pau Monné
2022-02-08 10:32 ` Oleksandr Andrushchenko
2022-02-07 16:08 ` Roger Pau Monné
2022-02-07 16:12 ` Jan Beulich
2022-02-07 14:28 ` Oleksandr Andrushchenko
2022-02-07 14:19 ` Roger Pau Monné
2022-02-07 14:27 ` Oleksandr Andrushchenko
2022-02-04 11:37 ` Oleksandr Andrushchenko
2022-02-04 12:15 ` Roger Pau Monné
2022-02-04 10:57 ` Roger Pau Monné
2022-02-04 6:34 ` [PATCH v6 04/13] vpci: restrict unhandled read/write operations for guests Oleksandr Andrushchenko
2022-02-04 14:11 ` Jan Beulich
2022-02-04 14:24 ` Oleksandr Andrushchenko
2022-02-08 8:00 ` Oleksandr Andrushchenko
2022-02-08 9:04 ` Jan Beulich
2022-02-08 9:09 ` Oleksandr Andrushchenko
2022-02-08 9:05 ` Roger Pau Monné
2022-02-08 9:10 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 05/13] vpci: add hooks for PCI device assign/de-assign Oleksandr Andrushchenko
2022-02-07 16:28 ` Jan Beulich
2022-02-08 8:32 ` Oleksandr Andrushchenko
2022-02-08 9:13 ` Jan Beulich
2022-02-08 9:27 ` Oleksandr Andrushchenko
2022-02-08 9:44 ` Jan Beulich
2022-02-08 9:55 ` Oleksandr Andrushchenko
2022-02-08 10:09 ` Jan Beulich
2022-02-08 10:22 ` Oleksandr Andrushchenko
2022-02-08 10:29 ` Jan Beulich
2022-02-08 10:52 ` Oleksandr Andrushchenko
2022-02-08 11:00 ` Jan Beulich
2022-02-08 11:25 ` Oleksandr Andrushchenko [this message]
2022-02-10 8:21 ` Oleksandr Andrushchenko
2022-02-10 9:22 ` Jan Beulich
2022-02-10 9:33 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 06/13] vpci/header: implement guest BAR register handlers Oleksandr Andrushchenko
2022-02-07 17:06 ` Jan Beulich
2022-02-08 8:06 ` Oleksandr Andrushchenko
2022-02-08 9:16 ` Jan Beulich
2022-02-08 9:29 ` Roger Pau Monné
2022-02-08 9:25 ` Roger Pau Monné
2022-02-08 9:31 ` Oleksandr Andrushchenko
2022-02-08 9:48 ` Jan Beulich
2022-02-08 9:57 ` Oleksandr Andrushchenko
2022-02-08 10:15 ` Jan Beulich
2022-02-08 10:29 ` Oleksandr Andrushchenko
2022-02-08 13:58 ` Roger Pau Monné
2022-02-04 6:34 ` [PATCH v6 07/13] vpci/header: handle p2m range sets per BAR Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 08/13] vpci/header: program p2m with guest BAR view Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 09/13] vpci/header: emulate PCI_COMMAND register for guests Oleksandr Andrushchenko
2022-02-04 14:25 ` Jan Beulich
2022-02-08 8:13 ` Oleksandr Andrushchenko
2022-02-08 9:33 ` Jan Beulich
2022-02-08 9:38 ` Oleksandr Andrushchenko
2022-02-08 9:52 ` Jan Beulich
2022-02-08 9:58 ` Oleksandr Andrushchenko
2022-02-08 11:11 ` Roger Pau Monné
2022-02-08 11:29 ` Oleksandr Andrushchenko
2022-02-08 14:09 ` Roger Pau Monné
2022-02-08 14:13 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 10/13] vpci/header: reset the command register when adding devices Oleksandr Andrushchenko
2022-02-04 14:30 ` Jan Beulich
2022-02-04 14:37 ` Oleksandr Andrushchenko
2022-02-07 7:29 ` Jan Beulich
2022-02-07 11:27 ` Oleksandr Andrushchenko
2022-02-07 12:38 ` Jan Beulich
2022-02-07 12:51 ` Oleksandr Andrushchenko
2022-02-07 12:54 ` Jan Beulich
2022-02-07 14:17 ` Oleksandr Andrushchenko
2022-02-07 14:31 ` Jan Beulich
2022-02-07 14:46 ` Oleksandr Andrushchenko
2022-02-07 15:05 ` Jan Beulich
2022-02-07 15:14 ` Oleksandr Andrushchenko
2022-02-07 15:28 ` Jan Beulich
2022-02-07 15:59 ` Oleksandr Andrushchenko
2022-02-10 12:54 ` Oleksandr Andrushchenko
2022-02-10 13:36 ` Jan Beulich
2022-02-10 13:56 ` Oleksandr Andrushchenko
2022-02-10 12:59 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 11/13] vpci: add initial support for virtual PCI bus topology Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 12/13] xen/arm: translate virtual PCI bus topology for guests Oleksandr Andrushchenko
2022-02-04 7:56 ` Jan Beulich
2022-02-04 8:18 ` Oleksandr Andrushchenko
2022-02-04 6:34 ` [PATCH v6 13/13] xen/arm: account IO handlers for emulated PCI MSI-X Oleksandr Andrushchenko
2022-02-11 15:28 ` Julien Grall
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=a0015951-6eff-38a8-a9f0-bdbc8bd51940@epam.com \
--to=oleksandr_andrushchenko@epam.com \
--cc=Artem_Mygaiev@epam.com \
--cc=Oleksandr_Tyshchenko@epam.com \
--cc=Volodymyr_Babchuk@epam.com \
--cc=andrew.cooper3@citrix.com \
--cc=bertrand.marquis@arm.com \
--cc=george.dunlap@citrix.com \
--cc=jbeulich@suse.com \
--cc=julien@xen.org \
--cc=paul@xen.org \
--cc=rahul.singh@arm.com \
--cc=roger.pau@citrix.com \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/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.
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 NNTP newsgroup(s).