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([2404:f801:9000:1a:efea::4b1]) by smtp.gmail.com with ESMTPSA id s13sm13014226pgi.36.2021.06.14.06.42.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Jun 2021 06:42:13 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: deadc58d-8e76-4385-90e2-726bcddf4c1a DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=BOH7Vu+778+ln6ekCo+GQvvDaGAsmqLU6p5AWEG4zZQ=; b=UL15DRdkb+5FCOorYR2hP1xNvGKF+hhVpp6Zgl0ZEc/kynMSrJYTv2B24Mo4Twd4OC vrOGM4BGqqMhwnmUjnn22As3rfqICUuSLDNUfN4x055EQkDEP6U8uykZ1ageGPFza6dy jotUZIYfU7sXGQAZHr4kuOdz1HN1DauLgWNH57sKiZSzR0dkndXAb/EFiLKvDgTKoc5n CF/y9pIWqcDDuK8B74SpZxdcaDkimajNnHxGveNvr7r1vPb4MaK8pI1+WDcP5irZNQIO K/ubQwcXeNSCfSAQihAGciweSNRMmdfdrpjGhRR3Ol9hGp7Cim/3jPpHV8NR+c4DzoMz 2CfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=BOH7Vu+778+ln6ekCo+GQvvDaGAsmqLU6p5AWEG4zZQ=; b=p9lhIZWdIFc6DT1u/BQJolvEwlezJU8vyMcJWWVuDO9/Lj9Gp6lDcw4I2AVu2iDsX8 8micOLf1hLuCJAgxhDJdgJclMLmMI8SePF9g0trWtU3OSMsAVzaKrU92rWiTvtcfkfnB JsbD7ufJVIfDKXNIt6NKqKdMkFBc4mmBz25m7FhRP7l1SVnxEKPd8EEayrGyY1sMJpJs Zl8AuYqzCWNsKWHbm24h6lqd/M42vCyZLfAXo140shU8SBsU/AQsrT7a1eUWcKChbc/u HQeqKUZ93PlehyrLrALamd8afc4MYDF91yIMKQB6M3lPGAQwKf0MEv36IZVV0e0nASCU MsjA== X-Gm-Message-State: AOAM532hBrnrpeprYCs0pKjz0/xk4G2pkKFPVGtECaNgLZOuxXzF8qCY n7DV2EAyKw7ZGjjtf+b2qNs= X-Google-Smtp-Source: ABdhPJzSD5SSODv3ZNJBk7/EJwQiektVm8x7/VFzAUKIi7xqvpG8L/erou4acHYRKMj3nTXmR0zAfQ== X-Received: by 2002:a63:f13:: with SMTP id e19mr16837169pgl.112.1623678133793; Mon, 14 Jun 2021 06:42:13 -0700 (PDT) Subject: Re: [RFC PATCH V3 08/11] swiotlb: Add bounce buffer remap address setting function From: Tianyu Lan To: Christoph Hellwig Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, rppt@kernel.org, hannes@cmpxchg.org, cai@lca.pw, krish.sadhukhan@oracle.com, saravanand@fb.com, Tianyu.Lan@microsoft.com, konrad.wilk@oracle.com, m.szyprowski@samsung.com, robin.murphy@arm.com, boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, joro@8bytes.org, will@kernel.org, xen-devel@lists.xenproject.org, davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com, iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, netdev@vger.kernel.org, vkuznets@redhat.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, sunilmut@microsoft.com References: <20210530150628.2063957-1-ltykernel@gmail.com> <20210530150628.2063957-9-ltykernel@gmail.com> <20210607064312.GB24478@lst.de> <48516ce3-564c-419e-b355-0ce53794dcb1@gmail.com> <20210614071223.GA30171@lst.de> <3e64e59b-7440-69a5-75c5-43225f3d6c0a@gmail.com> Message-ID: Date: Mon, 14 Jun 2021 21:42:00 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <3e64e59b-7440-69a5-75c5-43225f3d6c0a@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit On 6/14/2021 9:37 PM, Tianyu Lan wrote: > > > On 6/14/2021 3:12 PM, Christoph Hellwig wrote: >> On Mon, Jun 07, 2021 at 10:56:47PM +0800, Tianyu Lan wrote: >>> These addresses in extra address space works as system memory mirror. >>> The >>> shared memory with host in Isolation VM needs to be accessed via extra >>> address space which is above shared gpa boundary. >> >> Why? >> > > The shared_gpa_boundary in the AMD SEV SNP spec is called virtual top of > memory(vTOM). Memory addresses below vTOM are automatically treated as > private while memory above vTOM is treated as shared. Using vTOM to > separate memory in this way avoids the need to augment the standard x86 > page tables with C-bit markings, simplifying guest OS software. Here is the spec link and vTOM description is in the page 14. https://www.amd.com/system/files/TechDocs/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more.pdf Thanks.