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([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id e11sm1494456ejm.41.2021.09.13.22.36.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Sep 2021 22:36:45 -0700 (PDT) Subject: Re: [PATCH 1/2] x86: sgx_vepc: extract sgx_vepc_remove_page To: Jarkko Sakkinen , Dave Hansen , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: x86@kernel.org, linux-sgx@vger.kernel.org, dave.hansen@linux.intel.com, yang.zhong@intel.com References: <20210913131153.1202354-1-pbonzini@redhat.com> <20210913131153.1202354-2-pbonzini@redhat.com> <8105a379-195e-8c9b-5e06-f981f254707f@redhat.com> <06db5a41-3485-9141-10b5-56ca57ed1792@intel.com> <34632ea9-42d3-fdfa-ae47-e208751ab090@redhat.com> <3409573ac76aad2e7c3363343fc067d5b4621185.camel@kernel.org> From: Paolo Bonzini Message-ID: <734abf89-8be2-dd13-b649-fde5744ba465@redhat.com> Date: Tue, 14 Sep 2021 07:36:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <3409573ac76aad2e7c3363343fc067d5b4621185.camel@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/09/21 23:13, Jarkko Sakkinen wrote: >> Apart from reclaiming, /dev/sgx_vepc might disappear between the first >> open() and subsequent ones. > > If /dev/sgx_vepc disappears, why is it a problem *for the software*, and > not a sysadmin problem? Rather than disappearing, it could be that a program first gets all the resources it needs before it gets malicious input, and then enter a restrictive sandbox. In this case open() could be completely forbidden. I will improve the documentation and changelogs when I post the non-RFC version; that could have been done better, sorry. Paolo