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AJvYcCVWG978TC1K/6Y1OwljfARLbuvpcEe/7KI1cldGufxxmehZuxbshvqKkvAbSxCbh0a6nfXKOkJqNM5ypPA9zX6UziEf4V2W7pvOAmKR X-Gm-Message-State: AOJu0YzX3wrORjrXdUhD/BatmK9HuOk/tFVQFm36jlJZ4ytod/NENNc+ QXfI0qntxdbi1zotajtAKTgImmYOzHMVzDgMHyaXV+vMsRH4KxpTFVFgffwLCOz5vasSUMEfIEG SaA== X-Google-Smtp-Source: AGHT+IF1taDRJctSSVr2IasIIziXIfKJNIigxZpYaoBlxwyY2AZlY80I/q2z0jdfLZJ5lT9JqTpQH1/QQSk= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:e749:b0:1f3:95f:ba6d with SMTP id d9443c01a7336-1f3095fc09fmr1015685ad.5.1716226525207; Mon, 20 May 2024 10:35:25 -0700 (PDT) Date: Mon, 20 May 2024 10:35:23 -0700 In-Reply-To: <41d8ba3a48d33de82baa67ef5ee88e5f8995aea8.camel@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240501085210.2213060-1-michael.roth@amd.com> <20240501085210.2213060-14-michael.roth@amd.com> <41d8ba3a48d33de82baa67ef5ee88e5f8995aea8.camel@intel.com> Message-ID: Subject: Re: [PATCH v15 13/20] KVM: SEV: Implement gmem hook for initializing private pages From: Sean Christopherson To: Kai Huang Cc: "isaku.yamahata@gmail.com" , "kvm@vger.kernel.org" , Rick P Edgecombe , "michael.roth@amd.com" , "pankaj.gupta@amd.com" , "tglx@linutronix.de" , "tobin@ibm.com" , "liam.merwick@oracle.com" , "alpergun@google.com" , Tony Luck , "jmattson@google.com" , "luto@kernel.org" , "ak@linux.intel.com" , "pbonzini@redhat.com" , "pgonda@google.com" , "srinivas.pandruvada@linux.intel.com" , "slp@redhat.com" , "rientjes@google.com" , "peterz@infradead.org" , "linux-kernel@vger.kernel.org" , "dovmurik@linux.ibm.com" , "thomas.lendacky@amd.com" , "x86@kernel.org" , "bp@alien8.de" , "vkuznets@redhat.com" , "vbabka@suse.cz" , "ashish.kalra@amd.com" , "linux-coco@lists.linux.dev" , "nikunj.dadhania@amd.com" , Jorg Rodel , "mingo@redhat.com" , "sathyanarayanan.kuppuswamy@linux.intel.com" , "hpa@zytor.com" , "kirill@shutemov.name" , "jarkko@kernel.org" , "ardb@kernel.org" , "linux-crypto@vger.kernel.org" , "linux-mm@kvack.org" , "dave.hansen@linux.intel.com" Content-Type: text/plain; charset="us-ascii" On Mon, May 20, 2024, Kai Huang wrote: > On Wed, 2024-05-01 at 03:52 -0500, Michael Roth wrote: > > This will handle the RMP table updates needed to put a page into a > > private state before mapping it into an SEV-SNP guest. > > > > > > [...] > > > +int sev_gmem_prepare(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order) ... > +Rick, Isaku, > > I am wondering whether this can be done in the KVM page fault handler? No, because the state of a pfn in the RMP is tied to the guest_memfd inode, not to the file descriptor, i.e. not to an individual VM. And the NPT page tables are treated as ephemeral for SNP.