[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v5 01/11] xen/arm: xc_domain_ioport_permission(..) not supported on ARM.

  • To: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@xxxxxxxx>, Bertrand Marquis <bertrand.marquis@xxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Tue, 12 Oct 2021 12:20:34 +0200
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none
  • Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=vn6niiN5/polZaKHLQq7Qh7EXq+UY/qH5iK5QeVq9NU=; b=HZIM3l5sPF/NrGuMDkxMw6zZl7eQdODjWhjn9h0/x8FN+vy3MRlQFTwgMzih0dGbNAt/xS823BFJndJj/YxuwfhPE7rvH/OSysfBD3Q2lhYSVU1NbYFmFB08dnzGe3Wdfp/8SoZ6O/p84CWbkra3CS5FyqVEnROzHbeLP6S4TS+OLBuOTA66bOisdkAw6epoUghTMgSMVGZgttMLB+mwdnZ0quuMAOj5y9MAB18jUVjyePEeguF70pF7ev5Scb5UMIMRwluvEUTTTsRv14YjnofStI/hEArQFk8CwZJVv/cJjxvI/vXnHGZFkYtX/thX0m6IYtENa7jLqtvql11yVw==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=bJ53Z0FKC+pbHgk+xNphy/tUnlIbavGHw2+2/ACNZt8OM/nvsE7s9SnGjfjzHA1veE5uMSS0U0e2t7026iE8Y/0SGaM7UQWsAy1ST4unqP5R/zsdEE7L6WY9u1S13novpwsKRdYxUMfHXstwFSv/d9wqDUbGJedLfNF/ocjz4Dri1a013VQlt/IX7px959172Qps53m5MGvKRfx7bVjLMwSAKPcNt1IovYOz7q9C1D0QMRTDNb3TIWjHYMvX3vWFAWlEDiQmE+JkKkCfcr7lcLAXv9+Yi5AbYUYhpbGqT9k1ESd9zrUlip9w1wbRsVj3itiooiEBuT2uu7ynuSrMuA==
  • Authentication-results: citrix.com; dkim=none (message not signed) header.d=none;citrix.com; dmarc=none action=none header.from=suse.com;
  • Cc: Rahul Singh <rahul.singh@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Andre Przywara <Andre.Przywara@xxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>
  • Delivery-date: Tue, 12 Oct 2021 10:20:50 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 12.10.2021 12:06, Oleksandr Andrushchenko wrote:
> On 12.10.21 13:01, Jan Beulich wrote:
>> On 12.10.2021 11:38, Oleksandr Andrushchenko wrote:
>>> On 12.10.21 12:32, Jan Beulich wrote:
>>>> The minimal thing I'd suggest (or maybe you're doing this already)
>>>> would be to expose such BARs to the guest as r/o zero, rather than
>>>> letting their port nature "shine through".
>>> If we have the same, but baremetal then which entity disallows
>>> those BARs to shine?
>> I'm sorry, but I don't understand what you're trying to say.
>>> I mean that if guest wants to crash... why
>>> should we stop it and try emulating something special for it?
>> This isn't about a guest "wanting to crash", but a driver potentially
>> getting mislead into thinking that it can driver a device a certain
>> way.
> Well, for the guest, as we do not advertise IO in the emulated host
> bridge, the driver won't be able to allocate any IO at all. Thus, even
> if we have a BAR with PCI_BASE_ADDRESS_SPACE_IO bit set, the
> driver won't get anything. So, I think this is equivalent to a baremetal
> use-case where we have no IO supported by the host bridge and
> a device with IO BAR.

Oh, now I follow. Fair enough.




Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.