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Tue, 10 Nov 2026 05:47:15 -0800 (PST) Received: from [192.168.50.100] ([114.252.97.9]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8baaae3e110sm867486b3a.36.2026.11.10.05.47.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Nov 2026 05:47:15 -0800 (PST) Message-ID: <42ce73bc-0fb5-46d9-bc45-34a5bef25cb2@gmail.com> Date: Tue, 10 Nov 2026 21:47:05 +0800 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 9/9] iommu/riscv: Add riscv_iommu_attach_dev_nested To: Jason Gunthorpe , Gong Shuai Cc: tanchi25@mails.ucas.ac.cn, alex@ghiti.fr, andrew.jones@oss.qualcomm.com, anup@brainfault.org, aou@eecs.berkeley.edu, atish.patra@linux.dev, fangyu.yu@linux.alibaba.com, iommu@lists.linux.dev, joro@8bytes.org, kevin.tian@intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, palmer@dabbelt.com, pbonzini@redhat.com, pjw@kernel.org, robin.murphy@arm.com, seanjc@google.com, tomasz.jeznach@linux.dev, will@kernel.org, wu.fei9@sanechips.com.cn, zhao.qingye@sanechips.com.cn References: <20261105144944.10193-1-tanchi25@mails.ucas.ac.cn> <20261110115137.184160-1-gong.shuai@sanechips.com.cn> <20261110131658.GW663069@ziepe.ca> From: Gong Shuai In-Reply-To: <20261110131658.GW663069@ziepe.ca> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261110_054717_678647_B027870A X-CRM114-Status: GOOD ( 10.10 ) X-Spam-Score: -1.9 (-) X-BeenThere: kvm-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kvm-riscv" X-Spam-Status: No, score=-2.3 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Jason, On 11/10/2026 9:16 PM, Jason Gunthorpe wrote: > On Tue, Nov 10, 2026 at 07:51:37PM +0800, Gong Shuai wrote: > >> 2. Use the guest PSCID directly, but allocate a separate host GSCID for >> each vIOMMU. > > This is the right model. The viommu should allocate the GSCID directly > and keep it for the lifetime of the VM. Thanks for the confirmation. The new version will use this scheme. > >> 3. Share the GSCID and maintain a per-vIOMMU mapping from each guest >> PSCID to a host-allocated PSCID. > > AMD is doing this because they don't have something like a GSCID. Understood. This approach makes sense. Thanks, Shuai > > Jason -- kvm-riscv mailing list kvm-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kvm-riscv From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.227.201 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794318437; b=zRCc/Niy5kPKxIDByuRlYKscbDDxpSyDJD9XO3+KrNcTmcBze1auw910MW+Sx8SNfMnl NcrOzXLFIwiX9zMcqndrOEKuXCSm8nyUHUO2HKHlU7HpPjo5Wv6320pGzjqAXKE0A95mX Qh1LCiVzGx3aHiG/pHEp8Aufs/E1eeB8QLeKQwKIx84qYi9ScKFPJJ3obLnGgrXzPsS4E zldWmLkO29wYTNrgCc3nvkpWF3YvSoPn/o/ZUyoQTz33Z0qSMCZHuZrQ61a4okuvsONn3 8anm1zmqGs99W2qjOEdFxtH7w48wnhZb1k07/hwHWaOQZ/CK3oMfm/lqAyQlxOO13LA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794318437; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Message-ID:Date:MIME-Version:User-Agent:Subject:To:Cc:References:From: In-Reply-To:Content-Type:Content-Transfer-Encoding; 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Tue, 10 Nov 2026 05:47:15 -0800 (PST) Received: from [192.168.50.100] ([114.252.97.9]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8baaae3e110sm867486b3a.36.2026.11.10.05.47.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Nov 2026 05:47:15 -0800 (PST) Message-ID: <42ce73bc-0fb5-46d9-bc45-34a5bef25cb2@gmail.com> Date: Tue, 10 Nov 2026 21:47:05 +0800 X-Mailing-List: iommu@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 9/9] iommu/riscv: Add riscv_iommu_attach_dev_nested To: Jason Gunthorpe , Gong Shuai Cc: tanchi25@mails.ucas.ac.cn, alex@ghiti.fr, andrew.jones@oss.qualcomm.com, anup@brainfault.org, aou@eecs.berkeley.edu, atish.patra@linux.dev, fangyu.yu@linux.alibaba.com, iommu@lists.linux.dev, joro@8bytes.org, kevin.tian@intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, palmer@dabbelt.com, pbonzini@redhat.com, pjw@kernel.org, robin.murphy@arm.com, seanjc@google.com, tomasz.jeznach@linux.dev, will@kernel.org, wu.fei9@sanechips.com.cn, zhao.qingye@sanechips.com.cn References: <20261105144944.10193-1-tanchi25@mails.ucas.ac.cn> <20261110115137.184160-1-gong.shuai@sanechips.com.cn> <20261110131658.GW663069@ziepe.ca> From: Gong Shuai In-Reply-To: <20261110131658.GW663069@ziepe.ca> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Jason, On 11/10/2026 9:16 PM, Jason Gunthorpe wrote: > On Tue, Nov 10, 2026 at 07:51:37PM +0800, Gong Shuai wrote: > >> 2. Use the guest PSCID directly, but allocate a separate host GSCID for >> each vIOMMU. > > This is the right model. The viommu should allocate the GSCID directly > and keep it for the lifetime of the VM. Thanks for the confirmation. The new version will use this scheme. > >> 3. Share the GSCID and maintain a per-vIOMMU mapping from each guest >> PSCID to a host-allocated PSCID. > > AMD is doing this because they don't have something like a GSCID. Understood. This approach makes sense. Thanks, Shuai > > Jason From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B63B606A325 for ; Tue, 10 Nov 2026 13:47:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=ZoTg9ovC; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=QUeaehTf DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; 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Tue, 10 Nov 2026 05:47:15 -0800 (PST) Received: from [192.168.50.100] ([114.252.97.9]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8baaae3e110sm867486b3a.36.2026.11.10.05.47.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Nov 2026 05:47:15 -0800 (PST) Message-ID: <42ce73bc-0fb5-46d9-bc45-34a5bef25cb2@gmail.com> Date: Tue, 10 Nov 2026 21:47:05 +0800 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 9/9] iommu/riscv: Add riscv_iommu_attach_dev_nested To: Jason Gunthorpe , Gong Shuai Cc: tanchi25@mails.ucas.ac.cn, alex@ghiti.fr, andrew.jones@oss.qualcomm.com, anup@brainfault.org, aou@eecs.berkeley.edu, atish.patra@linux.dev, fangyu.yu@linux.alibaba.com, iommu@lists.linux.dev, joro@8bytes.org, kevin.tian@intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, palmer@dabbelt.com, pbonzini@redhat.com, pjw@kernel.org, robin.murphy@arm.com, seanjc@google.com, tomasz.jeznach@linux.dev, will@kernel.org, wu.fei9@sanechips.com.cn, zhao.qingye@sanechips.com.cn References: <20261105144944.10193-1-tanchi25@mails.ucas.ac.cn> <20261110115137.184160-1-gong.shuai@sanechips.com.cn> <20261110131658.GW663069@ziepe.ca> From: Gong Shuai In-Reply-To: <20261110131658.GW663069@ziepe.ca> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261110_054717_677153_0A274889 X-CRM114-Status: GOOD ( 10.10 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-riscv" X-Spam-Status: No, score=-2.3 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Jason, On 11/10/2026 9:16 PM, Jason Gunthorpe wrote: > On Tue, Nov 10, 2026 at 07:51:37PM +0800, Gong Shuai wrote: > >> 2. Use the guest PSCID directly, but allocate a separate host GSCID for >> each vIOMMU. > > This is the right model. The viommu should allocate the GSCID directly > and keep it for the lifetime of the VM. Thanks for the confirmation. The new version will use this scheme. > >> 3. Share the GSCID and maintain a per-vIOMMU mapping from each guest >> PSCID to a host-allocated PSCID. > > AMD is doing this because they don't have something like a GSCID. Understood. This approach makes sense. Thanks, Shuai > > Jason _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv