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([2404:f801:9000:18:efec::75b]) by smtp.gmail.com with ESMTPSA id y6-20020a17090322c600b001b9c960ffeasm1981122plg.47.2023.08.10.09.22.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 10 Aug 2023 09:22:46 -0700 (PDT) Message-ID: Date: Fri, 11 Aug 2023 00:22:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [EXTERNAL] [PATCH V2 2/9] x86/hyperv: Set Virtual Trust Level in VMBus init message To: Wei Liu , Saurabh Singh Sengar Cc: KY Srinivasan , Haiyang Zhang , Dexuan Cui , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "daniel.lezcano@linaro.org" , "arnd@arndb.de" , "Michael Kelley (LINUX)" , Tianyu Lan , "linux-arch@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "vkuznets@redhat.com" References: <20230627032248.2170007-1-ltykernel@gmail.com> <20230627032248.2170007-3-ltykernel@gmail.com> From: Tianyu Lan In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On 8/7/2023 12:48 PM, Wei Liu wrote: > On Fri, Jul 07, 2023 at 09:07:54AM +0000, Saurabh Singh Sengar wrote: >> >> >>> + >>> + ret = hv_do_hypercall(control, input, output); >>> + if (hv_result_success(ret)) >>> + vtl = output->as64.low & HV_X64_VTL_MASK; >>> + else >>> + pr_err("Hyper-V: failed to get VTL! %lld", ret); >> >> In case of error this function will return vtl=0, which can be the valid value of vtl. >> I suggest we initialize vtl with -1 so and then check for its return. >> >> This could be a good utility function which can be used for any Hyper-V VTL system, so think >> of making it global ? >> > > Tianyu -- your thought on this? In current user cases, the guest only runs in VTL0 and Hyper-V may return VTL error in some cases but kernel still may run with 0 as VTL. I just sent out v5 and set VTL to 0 by default if fail to get VTL from Hyper-V and give out a warning log. The get_vtl() is only called on enlightened SEV-SNP guest. If there is new case that needs handle the error from Hyper-V when call VTL hvcall, we may add the logic later.