From: "Bae, Chang Seok" <chang.seok.bae@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "bp@suse.de" <bp@suse.de>, "Lutomirski, Andy" <luto@kernel.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"Brown, Len" <len.brown@intel.com>,
"lenb@kernel.org" <lenb@kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"Macieira, Thiago" <thiago.macieira@intel.com>,
"Liu, Jing2" <jing2.liu@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH v10 04/28] x86/fpu/xstate: Modify address finders to handle both static and dynamic buffers
Date: Sun, 3 Oct 2021 22:35:41 +0000 [thread overview]
Message-ID: <B7F1A300-3E61-4CB4-8BCA-316FE68B7222@intel.com> (raw)
In-Reply-To: <87ee946g45.ffs@tglx>
On Oct 1, 2021, at 06:15, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Wed, Aug 25 2021 at 08:53, Chang S. Bae wrote:
>
>> Have all the functions finding XSTATE address take a struct fpu * pointer
>> in preparation for dynamic state buffer support.
>>
>> init_fpstate is a special case, which is indicated by a null pointer
>> parameter to get_xsave_addr() and __raw_xsave_addr().
>
> Same comment vs. subject. Prepare ...
How about:
"Prepare address finders to handle dynamic features"
>> + if (fpu)
>> + xsave = &fpu->state.xsave;
>> + else
>> + xsave = &init_fpstate.xsave;
>> +
>> + return xsave + xstate_comp_offsets[xfeature_nr];
>
> So you have the same conditionals and the same comments vs. that NULL
> pointer oddity how many times now all over the place?
>
> That can be completely avoided:
>
> Patch 1:
>
> -union fpregs_state init_fpstate __ro_after_init;
> +static union fpregs_state init_fpstate __ro_after_init;
> +struct fpu init_fpu = { .state = &init_fpstate } __ro_after_init;
>
> and make all users of init_fpstate access it through init_fpu.
>
> Patches 2..N which change arguments from fpregs_state to fpu:
>
> - fun(init_fpu->state);
> + fun(&init_fpu);
>
> Patch M which adds state_mask:
>
> @fpu__init_system_xstate()
> + init_fpu.state_mask = xfeatures_mask_all;
>
> Hmm?
Okay, a NULL pointer is odd and it as an argument should be avoided. Defining
a separate struct fpu for the initial state can make every function expect a
valid struct fpu pointer.
I think that the patch set will have such order (once [1] is dropped out) of,
- patch1 (new): a cleanup patch for fpstate_init_xstate() in patch1
- patch2 (new): the above init_fpu goes into this, and
- patch3-5: changes arguments to fpu,
- patch6 (new): finally patch 6 to add ->state_mask and ->state_size.
…
Thanks,
Chang
[1] https://lore.kernel.org/lkml/20210825155413.19673-2-chang.seok.bae@intel.com/
next prev parent reply other threads:[~2021-10-03 22:35 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 15:53 [PATCH v10 00/28] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 01/28] x86/fpu/xstate: Fix the state copy function to the XSTATE buffer Chang S. Bae
2021-10-01 12:44 ` Thomas Gleixner
2021-10-03 22:34 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 02/28] x86/fpu/xstate: Modify the initialization helper to handle both static and dynamic buffers Chang S. Bae
2021-10-01 12:45 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 03/28] x86/fpu/xstate: Modify state copy helpers " Chang S. Bae
2021-10-01 12:47 ` Thomas Gleixner
2021-10-03 22:42 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 04/28] x86/fpu/xstate: Modify address finders " Chang S. Bae
2021-10-01 13:15 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok [this message]
2021-10-04 12:54 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 05/28] x86/fpu/xstate: Add a new variable to indicate dynamic user states Chang S. Bae
2021-10-01 13:16 ` Thomas Gleixner
2021-10-03 22:35 ` Bae, Chang Seok
2021-10-04 12:57 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 06/28] x86/fpu/xstate: Add new variables to indicate dynamic XSTATE buffer size Chang S. Bae
2021-10-01 13:32 ` Thomas Gleixner
2021-10-03 22:36 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 07/28] x86/fpu/xstate: Calculate and remember dynamic XSTATE buffer sizes Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 08/28] x86/fpu/xstate: Convert the struct fpu 'state' field to a pointer Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 09/28] x86/fpu/xstate: Introduce helpers to manage the XSTATE buffer dynamically Chang S. Bae
2021-10-01 14:20 ` Thomas Gleixner
2021-10-03 22:36 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 10/28] x86/fpu/xstate: Update the XSTATE save function to support dynamic states Chang S. Bae
2021-10-01 15:41 ` Thomas Gleixner
2021-10-02 21:31 ` Thomas Gleixner
2021-10-02 22:54 ` Bae, Chang Seok
2021-10-05 8:16 ` Paolo Bonzini
2021-10-05 7:50 ` Paolo Bonzini
2021-10-05 9:55 ` Thomas Gleixner
2021-08-25 15:53 ` [PATCH v10 11/28] x86/fpu/xstate: Update the XSTATE buffer address finder " Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 12/28] x86/fpu/xstate: Update the XSTATE context copy function " Chang S. Bae
2021-08-25 15:53 ` [PATCH v10 13/28] x86/fpu/xstate: Use feature disable (XFD) to protect dynamic user state Chang S. Bae
2021-10-01 15:02 ` Thomas Gleixner
2021-10-01 15:10 ` Thomas Gleixner
2021-10-03 22:38 ` Bae, Chang Seok
2021-10-04 12:35 ` Thomas Gleixner
2021-10-01 20:20 ` Thomas Gleixner
2021-10-03 22:39 ` Bae, Chang Seok
2021-10-04 19:03 ` Thomas Gleixner
2021-10-03 22:41 ` Bae, Chang Seok
2021-08-25 15:53 ` [PATCH v10 14/28] x86/fpu/xstate: Support ptracer-induced XSTATE buffer expansion Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 15/28] x86/arch_prctl: Create ARCH_SET_STATE_ENABLE/ARCH_GET_STATE_ENABLE Chang S. Bae
2021-08-25 16:36 ` Bae, Chang Seok
2021-08-25 15:54 ` [PATCH v10 16/28] x86/fpu/xstate: Support both legacy and expanded signal XSTATE size Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 17/28] x86/fpu/xstate: Adjust the XSAVE feature table to address gaps in state component numbers Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 18/28] x86/fpu/xstate: Disable XSTATE support if an inconsistent state is detected Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 19/28] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 20/28] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 21/28] x86/fpu/amx: Initialize child's AMX state Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 22/28] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 23/28] x86/fpu/xstate: Skip writing zeros to signal frame for dynamic user states if in INIT-state Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 24/28] selftest/x86/amx: Test cases for the AMX state management Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 25/28] x86/insn/amx: Add TILERELEASE instruction to the opcode map Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 26/28] intel_idle/amx: Add SPR support with XTILEDATA capability Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 27/28] x86/fpu/xstate: Add a sanity check for XFD state when saving XSTATE Chang S. Bae
2021-08-25 15:54 ` [PATCH v10 28/28] x86/arch_prctl: ARCH_GET_FEATURES_WITH_KERNEL_ASSISTANCE Chang S. Bae
2021-09-30 21:12 ` [PATCH v10 00/28] x86: Support Intel Advanced Matrix Extensions Len Brown
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