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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-89a02f359f2sm37042696d6.24.2026.03.03.10.17.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2026 10:17:53 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vxUJd-00000004PZl-0bgZ; Tue, 03 Mar 2026 14:17:53 -0400 Date: Tue, 3 Mar 2026 14:17:53 -0400 From: Jason Gunthorpe To: Ankit Soni Cc: iommu@lists.linux.dev, vasant.hegde@amd.com, suravee.suthikulpanit@amd.com, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu/amd: Adhere to IVINFO[VASIZE] for address limits Message-ID: <20260303181753.GE964116@ziepe.ca> References: <20260302235715.GY44359@ziepe.ca> <20260303120554.GC964116@ziepe.ca> <4yddupv5soxmatbmcqqs4ndsffbls4r6eagoiaebalnlikx2jw@wtdby7qs6nz6> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4yddupv5soxmatbmcqqs4ndsffbls4r6eagoiaebalnlikx2jw@wtdby7qs6nz6> On Tue, Mar 03, 2026 at 05:11:07PM +0000, Ankit Soni wrote: > > I mean if FIELD_GET(IOMMU_IVINFO_VASIZE, amd_iommu_ivinfo) is 35 why > > not just pass it to hw_max_vasz_lg2 and be done with it? What is the > > point of limiting to only a few values? > > > > Jason > > I got your point, i added the check to match the spec, which defines valid > values are only 32, 40, 48, and 64. I don't think you should do that.. The valid values are the only ones a hypervisor should install, but the kernel should be permissive and accept everything.. Certainly it makes little sense to get something like 35 and expand it to 64. Jason