linux-kernel - Re: [PATCH v8 01/40] x86/compressed/64: detect/setup SEV/SME features earlier in boot

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0e09e98c-c013-e9a0-c4b9-279ef41ab0ff@intel.com>
Date:   Fri, 10 Dec 2021 11:23:24 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Borislav Petkov <bp@...en8.de>,
        Brijesh Singh <brijesh.singh@....com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-efi@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-coco@...ts.linux.dev, linux-mm@...ck.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        "H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        David Rientjes <rientjes@...gle.com>,
        Dov Murik <dovmurik@...ux.ibm.com>,
        Tobin Feldman-Fitzthum <tobin@....com>,
        Michael Roth <michael.roth@....com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Andi Kleen <ak@...ux.intel.com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        tony.luck@...el.com, marcorr@...gle.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com
Subject: Re: [PATCH v8 01/40] x86/compressed/64: detect/setup SEV/SME features
 earlier in boot

On 12/10/21 11:12 AM, Borislav Petkov wrote:
> On Fri, Dec 10, 2021 at 09:42:53AM -0600, Brijesh Singh wrote:
>> @@ -447,6 +446,23 @@ SYM_CODE_START(startup_64)
>>  	call	load_stage1_idt
>>  	popq	%rsi
>>  
>> +#ifdef CONFIG_AMD_MEM_ENCRYPT
> 
> I guess that ifdeffery is not needed.

I think sev_enable() is only defined in arch/x86/boot/compressed/sev.c,
which is compiled via:

        vmlinux-objs-$(CONFIG_AMD_MEM_ENCRYPT) += $(obj)/sev.o

So I think we either need the #ifdef or a stub for sev_enable()
somewhere else.

>> +	/*
>> +	 * Now that the stage1 interrupt handlers are set up, #VC exceptions from
>> +	 * CPUID instructions can be properly handled for SEV-ES guests.
>> +	 *
>> +	 * For SEV-SNP, the CPUID table also needs to be set up in advance of any
>> +	 * CPUID instructions being issued, so go ahead and do that now via
>> +	 * sev_enable(), which will also handle the rest of the SEV-related
>> +	 * detection/setup to ensure that has been done in advance of any dependent
>> +	 * code.
>> +	 */
>> +	pushq	%rsi
>> +	movq	%rsi, %rdi		/* real mode address */
>> +	call	sev_enable
>> +	popq	%rsi
>> +#endif