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From: Thomas Gleixner <tglx@linutronix.de>
To: Adamos Ttofari <attofari@amazon.de>
Cc: attofari@amazon.de, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Kyle Huey <me@kylehuey.com>,
	"Chang S. Bae" <chang.seok.bae@intel.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86: fpu: Keep xfd_state always in sync with MSR_IA32_XFD
Date: Fri, 12 May 2023 14:52:30 +0200	[thread overview]
Message-ID: <87y1ltbtkh.ffs@tglx> (raw)
In-Reply-To: <20230512113900.56393-1-attofari@amazon.de>

On Fri, May 12 2023 at 11:38, Adamos Ttofari wrote:
>  	if (cpu_feature_enabled(X86_FEATURE_XFD))
> -		wrmsrl(MSR_IA32_XFD, init_fpstate.xfd);
> +		xfd_set_state(init_fpstate.xfd);

> @@ -914,8 +915,7 @@ void fpu__resume_cpu(void)
>  				     xfeatures_mask_independent());
>  	}
>  
> -	if (fpu_state_size_dynamic())
> -		wrmsrl(MSR_IA32_XFD, current->thread.fpu.fpstate->xfd);
> +	xfd_update_state(current->thread.fpu.fpstate);

How is that supposed to work?

    this_cpu(xfd_state) == current->thread.fpu.fpstate->xfd

So the MSR write won't happen.

Thanks,

        tglx

  reply	other threads:[~2023-05-12 12:53 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-11 15:28 [PATCH] fpu: xstate: Keep xfd_state always in-sync with IA32_XFD MSR Adamos Ttofari
2023-05-11 17:59 ` Dave Hansen
2023-05-11 19:11 ` Thomas Gleixner
2023-05-12 17:46   ` Chang S. Bae
2023-05-12 11:38 ` [PATCH v2] x86: fpu: Keep xfd_state always in sync with MSR_IA32_XFD Adamos Ttofari
2023-05-12 12:52   ` Thomas Gleixner [this message]
2023-05-19 11:23     ` [PATCH v3] " Adamos Ttofari
2023-05-19 15:03       ` Thomas Gleixner
2023-05-19 22:21       ` Chang S. Bae
2023-06-03 15:24         ` [PATCH] selftests/x86/amx: Add a CPU hotplug test Chang S. Bae
2024-03-22 23:04       ` [PATCH v4] x86/fpu: Keep xfd_state always in sync with MSR_IA32_XFD Chang S. Bae
2024-03-24  3:15         ` [tip: x86/urgent] x86/fpu: Keep xfd_state " tip-bot2 for Adamos Ttofari
2023-05-16 21:35   ` [PATCH v2] x86: fpu: Keep xfd_state always " Chang S. Bae

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