Message-ID: <acba0832-9b11-c93d-7903-fff33f740605@intel.com>
Date:   Wed, 5 Jan 2022 12:27:08 -0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.4.1
Subject: Re: [PATCH v8 13/40] x86/kernel: Make the bss.decrypted section
 shared in RMP table
Content-Language: en-US
To:     Brijesh Singh <brijesh.singh@amd.com>,
        Venu Busireddy <venu.busireddy@oracle.com>
Cc:     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,
        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
References: <20211210154332.11526-1-brijesh.singh@amd.com>
 <20211210154332.11526-14-brijesh.singh@amd.com> <YdSKQKSTS83cRzGZ@dt>
 <18eadf9d-8e31-0945-ccf4-2cb72b8e0dd4@amd.com>
From:   Dave Hansen <dave.hansen@intel.com>
In-Reply-To: <18eadf9d-8e31-0945-ccf4-2cb72b8e0dd4@amd.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 1/5/22 11:52, Brijesh Singh wrote:
>>>           for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
>>> +            /*
>>> +             * When SEV-SNP is active then transition the page to shared in the RMP
>>> +             * table so that it is consistent with the page table attribute change.
>>> +             */
>>> +            early_snp_set_memory_shared(__pa(vaddr), __pa(vaddr), PTRS_PER_PMD);
>>
>> Shouldn't the first argument be vaddr as below?
> 
> Nope, sme_postprocess_startup() is called while we are fixing the 
> initial page table and running with identity mapping (so va == pa).

I'm not sure I've ever seen a line of code that wanted a comment so badly.