From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 2/3] x86/svm: Enumeration for CET
Date: Wed, 28 Apr 2021 15:17:32 +0100 [thread overview]
Message-ID: <b20b3a2c-9923-af5a-c04c-c381bdc15e60@citrix.com> (raw)
In-Reply-To: <55c50b27-e8cc-873e-e768-7e9dec6f06a0@suse.com>
On 28/04/2021 10:14, Jan Beulich wrote:
> On 27.04.2021 19:47, Andrew Cooper wrote:
>> On 27/04/2021 16:53, Jan Beulich wrote:
>>> On 26.04.2021 19:54, Andrew Cooper wrote:
>>>> @@ -497,7 +501,9 @@ struct vmcb_struct {
>>>> u64 rip;
>>>> u64 res14[11];
>>>> u64 rsp;
>>>> - u64 res15[3];
>>>> + u64 _msr_s_cet; /* offset 0x400 + 0x1E0 - cleanbit 12 */
>>>> + u64 _ssp; /* offset 0x400 + 0x1E8 | */
>>>> + u64 _msr_isst; /* offset 0x400 + 0x1F0 v */
>>>> u64 rax;
>>>> u64 star;
>>>> u64 lstar;
>>> Any reason for the leading underscores, when none of the neighboring
>>> fields have such?
>> Yes - they're covered by a cleanbit, and for better or worse, this is
>> our style.
> The underscore prefixes are, to my understanding, there only to
> emphasize that the fields shouldn't be accessed directly, but ...
>
>>> Did you perhaps mean to add VMCB_ACCESSORS()
>>> instances for them?
>> TBH, I opencoded the cleanbit handling because I thoroughly hate that
>> entire infrastructure.
> ... via this (or something with similar abstracting effect). So
> for any fields you mean to access directly they imo shouldn't be
> there. I particularly don't view them as indicators of being
> covered by cleanbits (if the respective accessors aren't used).
The leading underscores are enforced by 'vmcb->_ ## name' in
VMCB_ACCESSORS().
The cleanbits are the only reason we can't treat this as a simple struct.
~Andrew
next prev parent reply other threads:[~2021-04-28 14:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-26 17:54 [PATCH 0/3] x86: Initial pieces for guest CET support Andrew Cooper
2021-04-26 17:54 ` [PATCH 1/3] x86/hvm: Introduce experimental " Andrew Cooper
2021-04-27 15:47 ` Jan Beulich
2021-04-27 17:39 ` Andrew Cooper
2021-04-28 9:11 ` Jan Beulich
2021-04-28 17:54 ` Andrew Cooper
2021-04-29 9:07 ` Jan Beulich
2021-04-30 15:08 ` Andrew Cooper
2021-04-26 17:54 ` [PATCH 2/3] x86/svm: Enumeration for CET Andrew Cooper
2021-04-27 15:53 ` Jan Beulich
2021-04-27 17:47 ` Andrew Cooper
2021-04-28 9:14 ` Jan Beulich
2021-04-28 14:17 ` Andrew Cooper [this message]
2021-04-26 17:54 ` [PATCH 3/3] x86/VT-x: " Andrew Cooper
2021-04-27 15:56 ` Jan Beulich
2021-04-27 16:27 ` Andrew Cooper
2021-04-28 9:18 ` Jan Beulich
2021-04-27 6:46 ` [PATCH 0/3] x86: Initial pieces for guest CET support Jan Beulich
2021-04-27 10:13 ` Andrew Cooper
2021-04-28 12:25 ` Andrew Cooper
2021-04-28 13:03 ` Jan Beulich
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