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From: "Li, Xin3" <xin3.li@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"x86@kernel.org" <x86@kernel.org>
Cc: "mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"brgerst@gmail.com" <brgerst@gmail.com>,
	"Bae, Chang Seok" <chang.seok.bae@intel.com>
Subject: RE: [PATCH v3 4/6] x86/gsseg: move local_irq_save/restore() into asm_load_gs_index()
Date: Tue, 18 Oct 2022 17:25:31 +0000	[thread overview]
Message-ID: <BN6PR1101MB2161B983B1A85CE3803A3EF8A8289@BN6PR1101MB2161.namprd11.prod.outlook.com> (raw)
In-Reply-To: <8735bpbhat.ffs@tglx>

> >  static inline void native_load_gs_index(unsigned int selector)  {
> > -	unsigned long flags;
> > -
> > -	local_irq_save(flags);
> >  	asm_load_gs_index(selector);
> > -	local_irq_restore(flags);
> >  }
> 
> static inline void native_load_gs_index(unsigned int selector) {
> 	unsigned long flags;
> 
>         if (cpu_feature_enabled(LKGS)) {
>               native_lkgs(selector);
>         } else {
> 	      local_irq_save(flags);
>               asm_load_gs_index(selector);
> 	      local_irq_restore(flags);
>        }
> }
> 
> For paravirt enabled kernels we want during feature detection:
> 
>         if (cpu_feature_enabled(LKGS)))
>         	pv_ops.cpu.load_gs_index = native_lkgs;

If we use static_cpu_has in native_load_gs_index
       if (static_cpu_has(X86_FEATURE_LKGS)) {
               native_lkgs(selector);
       }

We don't have to change pv_ops.cpu.load_gs_index, right?

Thanks!
Xin

> 
> No?
> 
> Thanks,
> 
>         tglx

  reply	other threads:[~2022-10-18 17:26 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-13 20:01 [PATCH v3 0/6] Enable LKGS instruction Xin Li
2022-10-13 20:01 ` [PATCH v3 1/6] x86/cpufeature: add cpu feature bit for LKGS Xin Li
2022-10-13 20:01 ` [PATCH v3 2/6] x86/opcode: add LKGS instruction to x86-opcode-map Xin Li
2022-10-13 20:01 ` [PATCH v3 3/6] x86/gsseg: make asm_load_gs_index() take an u16 Xin Li
2022-10-14 12:28   ` David Laight
2022-10-15  0:13     ` Li, Xin3
2022-10-15  2:41     ` H. Peter Anvin
2022-10-17  7:49       ` David Laight
2022-10-17 18:39         ` H. Peter Anvin
2022-10-13 20:01 ` [PATCH v3 4/6] x86/gsseg: move local_irq_save/restore() into asm_load_gs_index() Xin Li
2022-10-15  8:51   ` Thomas Gleixner
2022-10-18 17:25     ` Li, Xin3 [this message]
2022-10-18 18:13       ` H. Peter Anvin
2022-10-18 21:29         ` Li, Xin3
2022-10-13 20:01 ` [PATCH v3 5/6] x86/gsseg: move load_gs_index() to its own header file Xin Li
2022-10-13 20:01 ` [PATCH v3 6/6] x86/gsseg: use the LKGS instruction if available for load_gs_index() Xin Li

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