Cc:     brijesh.singh@amd.com, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Jim Mattson <jmattson@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        David Rientjes <rientjes@google.com>,
        Dov Murik <dovmurik@linux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@ibm.com>,
        Borislav Petkov <bp@alien8.de>,
        Michael Roth <michael.roth@amd.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        Andi Kleen <ak@linux.intel.com>,
        "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
        tony.luck@intel.com, marcorr@google.com,
        sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v8 20/40] x86/sev: Use SEV-SNP AP creation to start
 secondary CPUs
To:     Dave Hansen <dave.hansen@intel.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        linux-coco@lists.linux.dev, linux-mm@kvack.org
References: <20211210154332.11526-1-brijesh.singh@amd.com>
 <20211210154332.11526-21-brijesh.singh@amd.com>
 <176b6163-fb2a-0339-e23f-2090ea78b4ed@intel.com>
From:   Brijesh Singh <brijesh.singh@amd.com>
Message-ID: <37fa05db-a528-09de-0c64-4c8b35f94f68@amd.com>
Date:   Wed, 12 Jan 2022 10:17:44 -0600
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On 12/10/21 12:50 PM, Dave Hansen wrote:
> On 12/10/21 7:43 AM, Brijesh Singh wrote:
>> +	vmsa->efer		= 0x1000;	/* Must set SVME bit */
>> +	vmsa->cr4		= cr4;
>> +	vmsa->cr0		= 0x60000010;
>> +	vmsa->dr7		= 0x400;
>> +	vmsa->dr6		= 0xffff0ff0;
>> +	vmsa->rflags		= 0x2;
>> +	vmsa->g_pat		= 0x0007040600070406ULL;
>> +	vmsa->xcr0		= 0x1;
>> +	vmsa->mxcsr		= 0x1f80;
>> +	vmsa->x87_ftw		= 0x5555;
>> +	vmsa->x87_fcw		= 0x0040;
> 
> This is a big fat pile of magic numbers.  We also have nice macros for a
> non-zero number of these, like:
> 
> 	#define MXCSR_DEFAULT 0x1f80
> 
> I understand that this probably _works_ as-is, but it doesn't look very
> friendly if someone else needs to go hack on it.
> 

APM documents the default value for the AP following the RESET or INIT, 
I will define macros and use them accordingly.

thx