linux-kernel - Re: [PATCHv6 20/30] x86/boot: Add a trampoline for booting APs via firmware handoff

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Date:   Thu, 17 Mar 2022 12:44:42 +0000
From:   Boris Petkov <bp@...en8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        tglx@...utronix.de, dave.hansen@...el.com, mingo@...hat.com,
        luto@...nel.org, peterz@...radead.org
CC:     sathyanarayanan.kuppuswamy@...ux.intel.com, aarcange@...hat.com,
        brijesh.singh@....com, ak@...ux.intel.com, david@...hat.com,
        dan.j.williams@...el.com, wanpengli@...cent.com, jgross@...e.com,
        linux-kernel@...r.kernel.org, hpa@...or.com, jmattson@...gle.com,
        pbonzini@...hat.com, seanjc@...gle.com, jpoimboe@...hat.com,
        vkuznets@...hat.com, joro@...tes.org, thomas.lendacky@....com,
        sdeep@...are.com, x86@...nel.org, knsathya@...nel.org,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        tony.luck@...el.com,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCHv6 20/30] x86/boot: Add a trampoline for booting APs via firmware handoff

On March 16, 2022 2:08:46 AM UTC, "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> wrote:
>diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
>index 48067af94678..35006e151774 100644
>--- a/arch/x86/include/asm/apic.h
>+++ b/arch/x86/include/asm/apic.h
>@@ -328,6 +328,8 @@ struct apic {
> 
> 	/* wakeup_secondary_cpu */
> 	int	(*wakeup_secondary_cpu)(int apicid, unsigned long start_eip);
>+	/* wakeup secondary CPU using 64-bit wakeup point */
>+	int	(*wakeup_secondary_cpu_64)(int apicid, unsigned long start_eip);
> 
> 	void	(*inquire_remote_apic)(int apicid);
> 
>diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h
>index 331474b150f1..fd6f6e5b755a 100644
>--- a/arch/x86/include/asm/realmode.h
>+++ b/arch/x86/include/asm/realmode.h
>@@ -25,6 +25,7 @@ struct real_mode_header {
> 	u32	sev_es_trampoline_start;
> #endif
> #ifdef CONFIG_X86_64
>+	u32	trampoline_start64;

I had already asked about those here: why do you need to add a new u32 here and can't use trampoline_start?

Ditto for the new function pointer too.

And yes, sev_es_trampoline_start is superfluous too.

-- 
Sent from a small device: formatting sux and brevity is inevitable.