[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH RFC 04/10] domain: update GADDR based runstate guest area
- To: Julien Grall <julien@xxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Tue, 20 Dec 2022 09:45:28 +0100
- 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=VE6tA7kXyTSra+PgEhnmQdQDP4peMDzI0mkHeoJ+oYQ=; b=WhSlySOSjgz8RZjHQSYabE2cHXxopAX6cw7Op48LZo/mivxZpv6ofwBuhMDeGbDj9hGjKkL0yhH2ykTR/ejHaxwracDlrxguxLJoQPscXj36/Wac914R6l8VgRQXhC4Q6O4QFPjZMpvbOOlyySMQ1pJZqpdK7URce8NJcfw9cm9t13F8IzduhVncLqwgOhh9s1U5p6+JbpS7ZtXdZeH1UHVU98+nsHehPoukH2SHU1Dy9hDCa4GKOEDNJmhcUb/ZF1aijbdlVUw4ukTV/kMYmwpEm2+hkw04Fd1BFo4SkXV5ieP3htE3UW4StW68CDp4PfClvuViNAMcCcxmvKRErg==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=mm1GiYoYe27E2zX3DDVJTKJJTcu7zlSiu8/KPmQf0XGKO+wzmLKFjLpLK5jgGaXgf99sMg9NXMMvzUDN9fq2wXe4wABclsLkmwzeCG5H2xKAUiegvyx7NjxjXUi0ipuqWbop0ZFJvr0q+/lGuofwo+8Ep0mVSMVbSeJR35S3YrCa5mqRuno8clQTlyBQB0vK45IZlI4brhXnVRlNNf1z/+RWpqn5w4t7bgDCgI+bVsL6DP1VN6PjdABFoA8Q3umAQKPYV29JKrSawPrHNOjjwlLGVw7DqulARUjWw3PmYKVbPBc4i2L0aMCHAdmqu7PVrBW1dkU6aC1ABUpnmUUPzA==
- Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com;
- Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- Delivery-date: Tue, 20 Dec 2022 08:45:35 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 20.12.2022 09:40, Julien Grall wrote:
> On 19/12/2022 12:48, Jan Beulich wrote:
>> On 16.12.2022 13:26, Julien Grall wrote:
>>> On 19/10/2022 08:41, Jan Beulich wrote:
>>>> RFC: HVM guests (on x86) can change bitness and hence layout (and size!
>>>> and alignment) of the runstate area. I don't think it is an option
>>>> to require 32-bit code to pass a range such that even the 64-bit
>>>> layout wouldn't cross a page boundary (and be suitably aligned). I
>>>> also don't see any other good solution, so for now a crude approach
>>>> with an extra boolean is used (using has_32bit_shinfo() isn't race
>>>> free and could hence lead to overrunning the mapped space).
>>>
>>> I think the extra check for 32-bit code to pass the check for 64-bit
>>> layout would be better.
>>
>> I'm afraid I can't derive from your reply what it is you actually want.
>
> I think for 32-bit call, we also want to check the address provide will
> also pass the 64-bit check (i.e. if used as a 64-bit layout, the area
> would not cross a page boundary and be suitably aligned).
But that's specifically what I say I don't think is an option. First and
foremost because of the implication on 32-bit callers: They're need to
use magic to get hold of the size of the 64-bit variant of the struct.
Jan
|
