From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Tim Deegan <tim@xen.org>
Cc: George Dunlap <george.dunlap@eu.citrix.com>,
Jan Beulich <JBeulich@suse.com>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v2 5/9] x86/pagewalk: Helpers for reserved bit handling
Date: Thu, 23 Mar 2017 17:02:28 +0000 [thread overview]
Message-ID: <18591f23-3a01-db1c-b284-6f17d4ebcdaf@citrix.com> (raw)
In-Reply-To: <20170323165520.GD8166@deinos.phlegethon.org>
On 23/03/17 16:55, Tim Deegan wrote:
> At 16:31 +0000 on 16 Mar (1489681899), Andrew Cooper wrote:
>> Some bits are unconditionally reserved in pagetable entries, or reserved
>> because of alignment restrictions. Other bits are reserved because of control
>> register configuration.
>>
>> Introduce helpers which take an individual vcpu and guest pagetable entry, and
>> calculates whether any reserved bits are set.
>>
>> While here, add a couple of newlines to aid readability.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> Reviewed-by: Tim Deegan <tim@xen.org>, although:
>
>> +/* Mask covering the reserved bits from superpage alignment. */
>> +#define SUPERPAGE_RSVD(bit) \
>> + (((1ULL << (bit)) - 1) & ~(_PAGE_PSE_PAT | (_PAGE_PSE_PAT - 1)))
> I think this will be wrong if we ever get l4 superpages, as the mask
> is only 32 bits wide.
What is 32 bits wide? 1ULL should cause everything else to be suitably
promoted, no?
~Andrew
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next prev parent reply other threads:[~2017-03-23 17:02 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-16 16:31 [PATCH v2 0/9] Fixes to pagetable handling Andrew Cooper
2017-03-16 16:31 ` [PATCH v2 1/9] x86/cpuid: Sort cpu_has_* predicates by feature number Andrew Cooper
2017-03-17 16:08 ` Jan Beulich
2017-03-16 16:31 ` [PATCH v2 2/9] x86/pagewalk: Use pointer syntax for pfec parameter Andrew Cooper
2017-03-17 16:09 ` Jan Beulich
2017-03-20 11:29 ` George Dunlap
2017-03-23 16:28 ` Tim Deegan
2017-03-16 16:31 ` [PATCH v2 3/9] x86/shadow: Drop VALID_GFN() Andrew Cooper
2017-03-23 16:30 ` Tim Deegan
2017-03-16 16:31 ` [PATCH v2 4/9] x86/pagewalk: Clean up guest_supports_* predicates Andrew Cooper
2017-03-20 8:45 ` Jan Beulich
2017-03-20 13:36 ` Andrew Cooper
2017-03-20 13:59 ` Jan Beulich
2017-03-23 17:32 ` Andrew Cooper
2017-03-24 7:19 ` Jan Beulich
2017-03-23 16:34 ` Tim Deegan
2017-03-16 16:31 ` [PATCH v2 5/9] x86/pagewalk: Helpers for reserved bit handling Andrew Cooper
2017-03-20 8:48 ` Jan Beulich
2017-03-23 16:55 ` Tim Deegan
2017-03-23 17:02 ` Andrew Cooper [this message]
2017-03-23 17:12 ` Tim Deegan
2017-03-23 17:35 ` Andrew Cooper
2017-03-24 5:45 ` Juergen Gross
2017-03-24 7:51 ` Jan Beulich
[not found] ` <58D4DDFF0200007800147138@suse.com>
2017-03-24 7:58 ` Juergen Gross
2017-03-24 8:25 ` Jan Beulich
2017-03-24 9:06 ` Andrew Cooper
2017-03-24 7:47 ` Jan Beulich
2017-03-24 8:36 ` Andrew Cooper
2017-03-16 16:31 ` [PATCH v2 6/9] x86/pagewalk: Re-implement the pagetable walker Andrew Cooper
2017-03-16 16:31 ` [PATCH v2 7/9] x86/shadow: Use the pagewalk reserved bits helpers Andrew Cooper
2017-03-16 17:25 ` Andrew Cooper
2017-03-20 8:53 ` Jan Beulich
2017-03-23 16:57 ` Tim Deegan
2017-03-16 16:31 ` [PATCH v2 8/9] x86/pagewalk: Improve the logic behind setting access and dirty bits Andrew Cooper
2017-03-20 9:03 ` Jan Beulich
2017-03-23 17:09 ` Tim Deegan
2017-03-23 17:40 ` Andrew Cooper
2017-03-16 16:31 ` [PATCH v2 9/9] x86/pagewalk: non-functional cleanup Andrew Cooper
2017-03-20 9:04 ` Jan Beulich
2017-03-23 17:10 ` Tim Deegan
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