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Wed, 17 Jul 2024 23:58:26 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG1CUDdb/pqONt4Je62LN6f3jGYm7SmTlakN/c+RI3Vxcjrt9NAAPcskLboMdbw0D7ZJe4dZQ== X-Received: by 2002:a05:6602:6e81:b0:80a:4582:cef1 with SMTP id ca18e2360f4ac-817125e2e78mr282663039f.3.1721285906340; Wed, 17 Jul 2024 23:58:26 -0700 (PDT) Received: from [10.72.116.35] ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-70b7eb9e26fsm9201874b3a.21.2024.07.17.23.58.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Jul 2024 23:58:25 -0700 (PDT) Message-ID: <817b5f2b-ec69-4a66-ad7b-ea8c8b9d0f24@redhat.com> Date: Thu, 18 Jul 2024 14:58:20 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/3] KVM: arm64: Disable fields that KVM doesn't know how to handle in ID_AA64PFR1_EL1 To: Oliver Upton Cc: Marc Zyngier , kvmarm@lists.linux.dev, Mark Brown , Eric Auger , Sebastian Ott , Cornelia Huck , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20240718035017.434996-1-shahuang@redhat.com> <20240718035017.434996-2-shahuang@redhat.com> Content-Language: en-US From: Shaoqin Huang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Oliver, On 7/18/24 14:09, Oliver Upton wrote: > Hi Shaoqin, > > On Wed, Jul 17, 2024 at 11:50:14PM -0400, Shaoqin Huang wrote: >> For some of the fields in the ID_AA64PFR1_EL1 register, KVM doesn't know >> how to handle them right now. So explicitly disable them in the register >> accessor, then those fields value will be masked to 0 even if on the >> hardware the field value is 1. > > It is probably important to note that the only reason this is safe to do > from a UAPI POV is that read_sanitised_ftr_reg() doesn't yet return a > nonzero value for any of these fields. (Reply again by the plain text) Yeah. That would be more clear if I tell the reader this information. Will add this when updating. Thanks, Shaoqin > -- Shaoqin