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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v8 02/17] x86: Support indirect thunks from assembly code
Date: Tue, 16 Jan 2018 13:55:29 +0000	[thread overview]
Message-ID: <3d30033d-0e63-a014-9edd-2e800069e7ae@citrix.com> (raw)
In-Reply-To: <5A5C9040020000780019EB46@prv-mh.provo.novell.com>

On 15/01/18 10:28, Jan Beulich wrote:
>>      ctxt->io_emul_stub[10] = 0xff;
>>      ctxt->io_emul_stub[11] = 0xd1;
>>  
>> +    /*
>> +     * 3 bytes of P6_NOPS.
>> +     * TODO: untangle ideal_nops from init/livepatch Kconfig options.
>> +     */
>> +    memcpy(&ctxt->io_emul_stub[12], "\x0f\x1f\x00", 3);
> Perhaps better "P6_NOP3" in the comment? And perhaps
> __stringify(P6_NOP3) in the memcpy() invocation, which may then
> make unnecessary that part of the comment?

__stringify(P6_NOP3) really doesn't do what you expect here.  This is
the preprocessed result:

__builtin_memcpy(&ctxt->io_emul_stub[12], "0x0f,0x1f,0x00", 3);

I've fixed up the other points, but left this one opencoded.

~Andrew

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  reply	other threads:[~2018-01-16 13:55 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-12 18:00 [PATCH v8 00/17] x86: Mitigations for SP2/CVE-2017-5715/Branch Target Injection Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 01/17] x86: Support compiling with indirect branch thunks Andrew Cooper
2018-01-14 19:48   ` David Woodhouse
2018-01-15  0:00     ` Andrew Cooper
2018-01-15  4:11     ` Konrad Rzeszutek Wilk
2018-01-15 10:14   ` Jan Beulich
2018-01-15 10:40     ` Andrew Cooper
2018-01-15 10:48       ` Jan Beulich
2018-01-12 18:00 ` [PATCH v8 02/17] x86: Support indirect thunks from assembly code Andrew Cooper
2018-01-15 10:28   ` Jan Beulich
2018-01-16 13:55     ` Andrew Cooper [this message]
2018-01-16 14:00       ` Jan Beulich
2018-02-04 10:57   ` David Woodhouse
2018-02-05  8:56     ` Jan Beulich
2018-01-12 18:00 ` [PATCH v8 03/17] x86/boot: Report details of speculative mitigations Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 04/17] x86/amd: Try to set lfence as being Dispatch Serialising Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 05/17] x86: Introduce alternative indirect thunks Andrew Cooper
2018-01-15 10:53   ` Jan Beulich
2018-01-12 18:00 ` [PATCH v8 06/17] x86/feature: Definitions for Indirect Branch Controls Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 07/17] x86/cmdline: Introduce a command line option to disable IBRS/IBPB, STIBP and IBPB Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 08/17] x86/msr: Emulation of MSR_{SPEC_CTRL, PRED_CMD} for guests Andrew Cooper
2018-01-16 11:10   ` David Woodhouse
2018-01-16 16:58     ` Andrew Cooper
2018-01-17  9:11       ` Jan Beulich
2018-01-17  9:39         ` Andrew Cooper
2018-01-12 18:00 ` [PATCH v8 09/17] x86/migrate: Move MSR_SPEC_CTRL on migrate Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 10/17] x86/hvm: Permit guests direct access to MSR_{SPEC_CTRL, PRED_CMD} Andrew Cooper
2018-01-15 11:11   ` Jan Beulich
2018-01-15 16:02     ` Boris Ostrovsky
2018-01-16  0:39     ` Tian, Kevin
2018-01-12 18:01 ` [PATCH v8 11/17] x86: Protect unaware domains from meddling hyperthreads Andrew Cooper
2018-01-15 11:26   ` Jan Beulich
2018-01-16 21:11     ` Andrew Cooper
2018-01-17  8:40       ` Jan Beulich
2018-01-17  8:43         ` Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 12/17] x86/entry: Organise the use of MSR_SPEC_CTRL at each entry/exit point Andrew Cooper
2018-01-15 12:09   ` Jan Beulich
2018-01-16 21:24     ` Andrew Cooper
2018-01-17  8:47       ` Jan Beulich
2018-01-17  9:25         ` Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 13/17] x86/boot: Calculate the most appropriate BTI mitigation to use Andrew Cooper
2018-01-16 14:10   ` Boris Ostrovsky
2018-01-16 14:13     ` Andrew Cooper
2018-01-16 14:25       ` Boris Ostrovsky
2018-01-16 15:12         ` Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 14/17] x86/entry: Clobber the Return Stack Buffer/Return Address Stack on entry to Xen Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 15/17] x86/ctxt: Issue a speculation barrier between vcpu contexts Andrew Cooper
2018-01-15 12:54   ` David Woodhouse
2018-01-15 13:02     ` Andrew Cooper
2018-01-15 13:23       ` David Woodhouse
2018-01-15 21:39         ` David Woodhouse
2018-01-17 17:26           ` David Woodhouse
2018-01-18  9:12             ` David Woodhouse
2018-01-12 18:01 ` [PATCH v8 16/17] x86/cpuid: Offer Indirect Branch Controls to guests Andrew Cooper
2018-01-12 18:01 ` [PATCH v8 17/17] x86/idle: Clear SPEC_CTRL while idle Andrew Cooper

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