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([2404:f801:9000:1a:efea::75b]) by smtp.gmail.com with ESMTPSA id l14-20020a17090a384e00b00250d670306esm1076450pjf.35.2023.05.17.02.01.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 May 2023 02:02:02 -0700 (PDT) Message-ID: Date: Wed, 17 May 2023 17:01:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [RFC PATCH V6 01/14] x86/sev: Add a #HV exception handler To: Peter Zijlstra Cc: luto@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, jgross@suse.com, tiala@microsoft.com, kirill@shutemov.name, jiangshan.ljs@antgroup.com, ashish.kalra@amd.com, srutherford@google.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, pawan.kumar.gupta@linux.intel.com, adrian.hunter@intel.com, daniel.sneddon@linux.intel.com, alexander.shishkin@linux.intel.com, sandipan.das@amd.com, ray.huang@amd.com, brijesh.singh@amd.com, michael.roth@amd.com, thomas.lendacky@amd.com, venu.busireddy@oracle.com, sterritt@google.com, tony.luck@intel.com, samitolvanen@google.com, fenghua.yu@intel.com, pangupta@amd.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org References: <20230515165917.1306922-1-ltykernel@gmail.com> <20230515165917.1306922-2-ltykernel@gmail.com> <20230516093010.GC2587705@hirez.programming.kicks-ass.net> From: Tianyu Lan In-Reply-To: <20230516093010.GC2587705@hirez.programming.kicks-ass.net> 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 5/16/2023 5:30 PM, Peter Zijlstra wrote: > On Mon, May 15, 2023 at 12:59:03PM -0400, Tianyu Lan wrote: >> From: Tianyu Lan >> >> Add a #HV exception handler that uses IST stack. >> > Urgh.. that is entirely insufficient. Like it doesn't even begin to > start to cover things. > > The whole existing VC IST stack abuse is already a nightmare and you're > duplicating that.. without any explanation for why this would be needed > and how it is correct. > > Please try again. Hi Peter: Thanks for your review. Will add more explanation in the next version.