[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v4 02/10] x86/mm: Avoid hard-coding PAT in get_page_from_l1e()
- To: Demi Marie Obenour <demi@xxxxxxxxxxxxxxxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Fri, 16 Dec 2022 08:46:36 +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=KozOlaVwm4ZSiH5TUzXqtRoo4M5Y8JY11JQYlZ3cV7o=; b=QlJ+CmfF8xF0RT2hhqS3mHxv8cJ/zsmnXRwUdm98jUAP+kR8lkANEK8A4Nhll5GcpRxTrkglagKgtct7QzA7WflERcin6gvzxrFZV7DmMQ4+G7M6uYEvnunKgE1+OJb8RCQka95bggrX3vxtT9+Q7A7c6SV2hqTxvKZuAtzJmXV7HHaNgXoOwm+9Zj0JrxvkAnlL6IQRLMFgxGmzWFNXJMNmvlah6h+VamKEWSCRSVFJqpH/H3c7JIWUy+foJ8DMC+gpcoKMIYdP1XxSnGk9nOHB7uLuVuGsolL97RW3KgY71GnU6Zx4oPJ983BzuM5Ik01uDxKIgZ127/xX7diZXg==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=OrGz+PS25lMN1jKa4ab6oock/cwsFagyBsFP5R6145PBcPJd6MnLEwB7XVeH2wVbPBRF9wSRnTq302U1wqnL+n6vvcUFFNNiLTVfqut7FBiau/FRpHqGwFJ6DMYK5RLaDvxw+z1QlVRAJzuI978oek/K5V2DGcvufEJMiq/8TtNmvt+3ykpxbTdICII9lW3+Cdx7Duk0UOqO+fVG1ThsxbWRXBIuzAldhVNZcpZBYFKeG824MHBeSc2lCaUodOcGpA7zyqMEVpR6+M9E4vmg9QV7hsFOjVbmuNjlwotkeYM01celOoP1emhb3V3KOYY+1ETVNHi5A2fYlB+KbjYhvA==
- Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=suse.com;
- Cc: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Jun Nakajima <jun.nakajima@xxxxxxxxx>, Kevin Tian <kevin.tian@xxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Tim Deegan <tim@xxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Fri, 16 Dec 2022 07:46:42 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 16.12.2022 03:25, Demi Marie Obenour wrote:
>> --- a/xen/arch/x86/include/asm/processor.h
>> +++ b/xen/arch/x86/include/asm/processor.h
>> @@ -100,6 +100,14 @@
>>
>> #ifndef __ASSEMBLY__
>>
>> +/* Convert from PAT/PCD/PWT embedded in PTE flags to actual cacheability
>> value */
>> +static inline unsigned int pte_flags_to_cacheability(unsigned int flags)
>> +{
>> + unsigned int pat_shift = ((flags & _PAGE_PAT) >> 2) |
>> + (flags & (_PAGE_PCD|_PAGE_PWT));
>
> This could also be written as
>
> unsigned int pat_shift = pte_flags_to_cacheattr(flags) << 3;
>
> which might be easiser to read.
Indeed. And then also be placed next to the other function (provided
we want this to be a globally visible helper in the first place).
But first of all Andrew's comment wants addressing - if the code
using this new helper is to be deleted, then the new helper doesn't
need getting into proper shape and place.
Jan
|
