linux-kernel - Re: [RFC 02/14] x86/apic: Initialize Secure AVIC APIC backing page

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Message-ID: <20241023163626.GKZxkmCi8ZyyCZlkrX@fat_crate.local>
Date: Wed, 23 Oct 2024 18:36:26 +0200
From: Borislav Petkov <bp@...en8.de>
To: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
Cc: linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	dave.hansen@...ux.intel.com, Thomas.Lendacky@....com,
	nikunj@....com, Santosh.Shukla@....com, Vasant.Hegde@....com,
	Suravee.Suthikulpanit@....com, David.Kaplan@....com, x86@...nel.org,
	hpa@...or.com, peterz@...radead.org, seanjc@...gle.com,
	pbonzini@...hat.com, kvm@...r.kernel.org
Subject: Re: [RFC 02/14] x86/apic: Initialize Secure AVIC APIC backing page

On Fri, Sep 13, 2024 at 05:06:53PM +0530, Neeraj Upadhyay wrote:
> @@ -61,8 +65,30 @@ static void x2apic_savic_send_IPI_mask_allbutself(const struct cpumask *mask, in
>  	__send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
>  }
>  
> +static void x2apic_savic_setup(void)
> +{
> +	void *backing_page;
> +	enum es_result ret;
> +	unsigned long gpa;
> +
> +	if (this_cpu_read(savic_setup_done))

I'm sure you can get rid of that silly bool. Like check the apic_backing_page
pointer instead and use that pointer to verify whether the per-CPU setup has
been done successfully.

> +		return;
> +
> +	backing_page = this_cpu_read(apic_backing_page);
> +	gpa = __pa(backing_page);
> +	ret = sev_notify_savic_gpa(gpa);
> +	if (ret != ES_OK)
> +		snp_abort();
> +	this_cpu_write(savic_setup_done, true);
> +}

-- 
Regards/Gruss,
    Boris.

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