[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [PATCH 1/6] x86/msr: Clean up the MSR_EFER constants
- To: Jan Beulich <JBeulich@xxxxxxxx>
- From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
- Date: Fri, 7 Sep 2018 15:47:36 +0100
- Autocrypt: addr=andrew.cooper3@xxxxxxxxxx; prefer-encrypt=mutual; keydata= xsFNBFLhNn8BEADVhE+Hb8i0GV6mihnnr/uiQQdPF8kUoFzCOPXkf7jQ5sLYeJa0cQi6Penp VtiFYznTairnVsN5J+ujSTIb+OlMSJUWV4opS7WVNnxHbFTPYZVQ3erv7NKc2iVizCRZ2Kxn srM1oPXWRic8BIAdYOKOloF2300SL/bIpeD+x7h3w9B/qez7nOin5NzkxgFoaUeIal12pXSR Q354FKFoy6Vh96gc4VRqte3jw8mPuJQpfws+Pb+swvSf/i1q1+1I4jsRQQh2m6OTADHIqg2E ofTYAEh7R5HfPx0EXoEDMdRjOeKn8+vvkAwhviWXTHlG3R1QkbE5M/oywnZ83udJmi+lxjJ5 YhQ5IzomvJ16H0Bq+TLyVLO/VRksp1VR9HxCzItLNCS8PdpYYz5TC204ViycobYU65WMpzWe LFAGn8jSS25XIpqv0Y9k87dLbctKKA14Ifw2kq5OIVu2FuX+3i446JOa2vpCI9GcjCzi3oHV e00bzYiHMIl0FICrNJU0Kjho8pdo0m2uxkn6SYEpogAy9pnatUlO+erL4LqFUO7GXSdBRbw5 gNt25XTLdSFuZtMxkY3tq8MFss5QnjhehCVPEpE6y9ZjI4XB8ad1G4oBHVGK5LMsvg22PfMJ ISWFSHoF/B5+lHkCKWkFxZ0gZn33ju5n6/FOdEx4B8cMJt+cWwARAQABzSlBbmRyZXcgQ29v cGVyIDxhbmRyZXcuY29vcGVyM0BjaXRyaXguY29tPsLBegQTAQgAJAIbAwULCQgHAwUVCgkI CwUWAgMBAAIeAQIXgAUCWKD95wIZAQAKCRBlw/kGpdefoHbdD/9AIoR3k6fKl+RFiFpyAhvO 59ttDFI7nIAnlYngev2XUR3acFElJATHSDO0ju+hqWqAb8kVijXLops0gOfqt3VPZq9cuHlh IMDquatGLzAadfFx2eQYIYT+FYuMoPZy/aTUazmJIDVxP7L383grjIkn+7tAv+qeDfE+txL4 SAm1UHNvmdfgL2/lcmL3xRh7sub3nJilM93RWX1Pe5LBSDXO45uzCGEdst6uSlzYR/MEr+5Z JQQ32JV64zwvf/aKaagSQSQMYNX9JFgfZ3TKWC1KJQbX5ssoX/5hNLqxMcZV3TN7kU8I3kjK mPec9+1nECOjjJSO/h4P0sBZyIUGfguwzhEeGf4sMCuSEM4xjCnwiBwftR17sr0spYcOpqET ZGcAmyYcNjy6CYadNCnfR40vhhWuCfNCBzWnUW0lFoo12wb0YnzoOLjvfD6OL3JjIUJNOmJy RCsJ5IA/Iz33RhSVRmROu+TztwuThClw63g7+hoyewv7BemKyuU6FTVhjjW+XUWmS/FzknSi dAG+insr0746cTPpSkGl3KAXeWDGJzve7/SBBfyznWCMGaf8E2P1oOdIZRxHgWj0zNr1+ooF /PzgLPiCI4OMUttTlEKChgbUTQ+5o0P080JojqfXwbPAyumbaYcQNiH1/xYbJdOFSiBv9rpt TQTBLzDKXok86M7BTQRS4TZ/ARAAkgqudHsp+hd82UVkvgnlqZjzz2vyrYfz7bkPtXaGb9H4 Rfo7mQsEQavEBdWWjbga6eMnDqtu+FC+qeTGYebToxEyp2lKDSoAsvt8w82tIlP/EbmRbDVn 7bhjBlfRcFjVYw8uVDPptT0TV47vpoCVkTwcyb6OltJrvg/QzV9f07DJswuda1JH3/qvYu0p vjPnYvCq4NsqY2XSdAJ02HrdYPFtNyPEntu1n1KK+gJrstjtw7KsZ4ygXYrsm/oCBiVW/OgU g/XIlGErkrxe4vQvJyVwg6YH653YTX5hLLUEL1NS4TCo47RP+wi6y+TnuAL36UtK/uFyEuPy wwrDVcC4cIFhYSfsO0BumEI65yu7a8aHbGfq2lW251UcoU48Z27ZUUZd2Dr6O/n8poQHbaTd 6bJJSjzGGHZVbRP9UQ3lkmkmc0+XCHmj5WhwNNYjgbbmML7y0fsJT5RgvefAIFfHBg7fTY/i kBEimoUsTEQz+N4hbKwo1hULfVxDJStE4sbPhjbsPCrlXf6W9CxSyQ0qmZ2bXsLQYRj2xqd1 bpA+1o1j2N4/au1R/uSiUFjewJdT/LX1EklKDcQwpk06Af/N7VZtSfEJeRV04unbsKVXWZAk uAJyDDKN99ziC0Wz5kcPyVD1HNf8bgaqGDzrv3TfYjwqayRFcMf7xJaL9xXedMcAEQEAAcLB XwQYAQgACQUCUuE2fwIbDAAKCRBlw/kGpdefoG4XEACD1Qf/er8EA7g23HMxYWd3FXHThrVQ HgiGdk5Yh632vjOm9L4sd/GCEACVQKjsu98e8o3ysitFlznEns5EAAXEbITrgKWXDDUWGYxd pnjj2u+GkVdsOAGk0kxczX6s+VRBhpbBI2PWnOsRJgU2n10PZ3mZD4Xu9kU2IXYmuW+e5KCA vTArRUdCrAtIa1k01sPipPPw6dfxx2e5asy21YOytzxuWFfJTGnVxZZSCyLUO83sh6OZhJkk b9rxL9wPmpN/t2IPaEKoAc0FTQZS36wAMOXkBh24PQ9gaLJvfPKpNzGD8XWR5HHF0NLIJhgg 4ZlEXQ2fVp3XrtocHqhu4UZR4koCijgB8sB7Tb0GCpwK+C4UePdFLfhKyRdSXuvY3AHJd4CP 4JzW0Bzq/WXY3XMOzUTYApGQpnUpdOmuQSfpV9MQO+/jo7r6yPbxT7CwRS5dcQPzUiuHLK9i nvjREdh84qycnx0/6dDroYhp0DFv4udxuAvt1h4wGwTPRQZerSm4xaYegEFusyhbZrI0U9tJ B8WrhBLXDiYlyJT6zOV2yZFuW47VrLsjYnHwn27hmxTC/7tvG3euCklmkn9Sl9IAKFu29RSo d5bD8kMSCYsTqtTfT6W4A3qHGvIDta3ptLYpIAOD2sY3GYq2nf3Bbzx81wZK14JdDDHUX2Rs 6+ahAA==
- Cc: Xen-devel <xen-devel@xxxxxxxxxxxxx>, Wei Liu <wei.liu2@xxxxxxxxxx>, Roger Pau Monne <roger.pau@xxxxxxxxxx>
- Delivery-date: Fri, 07 Sep 2018 14:47:45 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Openpgp: preference=signencrypt
On 28/06/18 14:56, Jan Beulich wrote:
>>>> On 28.06.18 at 15:36, <andrew.cooper3@xxxxxxxxxx> wrote:
>> On 28/06/18 14:00, Jan Beulich wrote:
>>>>>> On 26.06.18 at 15:18, <andrew.cooper3@xxxxxxxxxx> wrote:
>>>> @@ -49,6 +28,18 @@
>>>> #define ARCH_CAPS_RSBA (_AC(1, ULL) << 2)
>>>> #define ARCH_CAPS_SSB_NO (_AC(1, ULL) << 4)
>>>>
>>>> +#define MSR_EFER 0xc0000080 /* Extended Feature
>>>> Enable Register */
>>>> +#define EFER_SCE (_AC(1, ULL) << 0) /* SYSCALL
>>>> Enable */
>>>> +#define EFER_LME (_AC(1, ULL) << 8) /* Long Mode
>>>> Enable */
>>>> +#define EFER_LMA (_AC(1, ULL) << 10) /* Long Mode
>>>> Active */
>>>> +#define EFER_NXE (_AC(1, ULL) << 11) /* No Execute
>>>> Enable */
>>>> +#define EFER_SVME (_AC(1, ULL) << 12) /* Secure
>>>> Virtual Machine Enable */
>>>> +#define EFER_LMSLE (_AC(1, ULL) << 13) /* Long Mode
>>>> Segment Limit Enable */
>>>> +#define EFER_FFXSE (_AC(1, ULL) << 14) /* Fast
>>>> FXSAVE/FXRSTOR */
>>>> +
>>>> +#define EFER_KNOWN_MASK (EFER_SCE | EFER_LME | EFER_LMA | EFER_NXE | \
>>>> + EFER_SVME | EFER_LMSLE | EFER_FFXSE)
>>> When meaning to clean up and consolidate these and others, why
>>> don't we switch to architectural MSR names at the same time? While
>>> this will increase source size a little, it'll
>>> - allow grep-ing for the MSRs' uses by their SDM names,
>>> - significantly reduce the risk of name clashes with something on e.g.
>>> the arm side (EFER may not be the most risky one here, but some
>>> of the subsequent patches certainly seem to incur such a risk).
>>>
>>> I.e. here MSR_IA32_EFER and IA32_EFER_SCE etc.
>>>
>>> Other than this I'm certainly fine in general with this cleanup.
>> Removing IA32 is a deliberate and intended properly. The
>> non-architectural vs architectural nature of MSRs changes over time
>> meaning the names here get stale.
> But I don't think they've ever changed from IA32 to no IA32. I.e.
> once an MSR becomes architectural, we could rename it once and
> be done.
In some cases, use of the IA32 prefix is different per vendor.
>> As for grepability, most MSRs can't currently be located like that, and
>> (naming instability aside) I believe the reduction in code volume is
>> more important property to have.
> The fact that "most MSRs can't currently be located like that" is
> what I've long hoped we could overcome.
Why? Its not like you can grep the docs themselves. If you are trying
to cross reference, going by number is far easier.
I don't see any convincing reason
>
>> There is no chance of clashing with ARM, as these are all arch-specific
>> constants. Any common code referencing them should be fixed by becoming
>> arch-specific code.
> The risk is for this to go unnoticed for a while.
You can make that argument about any choice of naming. Having an
unnecessarily verbose constant name doesn't alter the risk.
~Andrew
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
