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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49230a4f8d7sm188031235e9.5.2026.06.17.14.54.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Jun 2026 14:54:18 -0700 (PDT) Date: Wed, 17 Jun 2026 22:54:16 +0100 From: David Laight To: Guo Ren Cc: zhangzhanpeng.jasper@bytedance.com, alex@ghiti.fr, aou@eecs.berkeley.edu, cuiyunhui@bytedance.com, iommu@lists.linux.dev, joro@8bytes.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, luxu.kernel@bytedance.com, palmer@dabbelt.com, pjw@kernel.org, robin.murphy@arm.com, tjeznach@rivosinc.com, will@kernel.org, yuanzhu@bytedance.com Subject: Re: [PATCH v1] iommu/riscv: Support 32-bit register accesses Message-ID: <20260617225416.0c5a79b0@pumpkin> In-Reply-To: References: <20260615064855.90316-1-zhangzhanpeng.jasper@bytedance.com> <20260615123821.373248-1-guoren@kernel.org> <20260616113651.1048a19a@pumpkin> <20260616205147.6aa7df98@pumpkin> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260617_145421_114183_F5C869AC X-CRM114-Status: GOOD ( 32.97 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org T24gVGh1LCAxOCBKdW4gMjAyNiAwMDoyNDoxMiArMDgwMApHdW8gUmVuIDxndW9yZW5Aa2VybmVs Lm9yZz4gd3JvdGU6Cgo+IE9uIFdlZCwgSnVuIDE3LCAyMDI2IGF0IDM6NTHigK9BTSBEYXZpZCBM YWlnaHQKPiA8ZGF2aWQubGFpZ2h0LmxpbnV4QGdtYWlsLmNvbT4gd3JvdGU6Cj4gPgo+ID4gT24g VHVlLCAxNiBKdW4gMjAyNiAyMzo0NzowNSArMDgwMAo+ID4gR3VvIFJlbiA8Z3VvcmVuQGtlcm5l bC5vcmc+IHdyb3RlOgo+ID4gIAo+ID4gPiBPbiBUdWUsIEp1biAxNiwgMjAyNiBhdCA2OjM24oCv UE0gRGF2aWQgTGFpZ2h0Cj4gPiA+IDxkYXZpZC5sYWlnaHQubGludXhAZ21haWwuY29tPiB3cm90 ZTogIAo+ID4gPiA+Cj4gPiA+ID4gT24gTW9uLCAxNSBKdW4gMjAyNiAxMjozODoxNyArMDAwMAo+ ID4gPiA+IEd1byBSZW4gPGd1b3JlbkBrZXJuZWwub3JnPiB3cm90ZToKPiA+ID4gPiAgCj4gPiA+ ID4gPiBIaSBaaGFucGVuZyBaaGFuZywgIAo+ID4gPiA+IC4uICAKPiA+ID4gPiA+IDMuIE9ubHkg cGVyZm9ybWFuY2UtbW9uaXRvcmluZyBjb3VudGVycyByZXF1aXJlIDY0LWJpdCBJTyBhY2Nlc3Mg b3IgdGhlCj4gPiA+ID4gPiBoaWdoLWxvdy1oaWdoIGRvLXdoaWxlIHJldHJ5IHN0cmF0ZWd5LiBG b3Igb3JkaW5hcnkgc3RhdHVzIGFuZCBjb250cm9sCj4gPiA+ID4gPiBNTUlPIHJlZ2lzdGVycywg YSBzaW5nbGUgcmVhZCBpcyBzdWZmaWNpZW50LiAgCj4gPiA+ID4KPiA+ID4gPiBBY3R1YWxseSB0 aGlzIHNlcXVlbmNlIHNob3VsZCBiZSBlbm91Z2ggZm9yIGEgY291bnRlcjoKPiA+ID4gPiAgICAg ICAgIGhpID0gcmVhZF9oaSgpOwo+ID4gPiA+ICAgICAgICAgbG8gPSByZWFkX2xvKCk7Cj4gPiA+ ID4gICAgICAgICBpZiAoaGkgIT0gcmVhZF9oaSgpKSB7Cj4gPiA+ID4gICAgICAgICAgICAgICAg IC8vIFBpY2sgYSB2YWx1ZSB0aGF0IGhhcHBlbmVkIHdoaWxlIGRvaW5nIHRoZSByZWFkcy4KPiA+ ID4gPiAgICAgICAgICAgICAgICAgaGkrKzsKPiA+ID4gPiAgICAgICAgICAgICAgICAgbG8gPSAw Owo+ID4gPiA+ICAgICAgICAgfSAgCj4gPiA+IFRoaXMgaXMgbm90IGEgZnJlZSBvcHRpbWl6YXRp b24g4oCUIGl0IGRvZXMgbm90IHByZXNlcnZlIHRoZSBzYW1lCj4gPiA+IHNlbWFudGljcyBhcyBh biBhdG9taWMgNjQtYml0IHJlYWQuIFRoZXJlIGFyZSBhdCBsZWFzdCB0d28gY29ycmVjdG5lc3MK PiA+ID4gaXNzdWVzOgo+ID4gPgo+ID4gPiAxLiBMb3NzIG9mIHByZWNpc2lvbjogSWYgaGkgY2hh bmdlZCBkdXJpbmcgdGhlIHJlYWQsIHNldHRpbmcgbG8gPSAwCj4gPiA+IGRpc2NhcmRzIHRoZSBh Y3R1YWwgbG8gdmFsdWUuIFRoZSBjb3JyZWN0IGFwcHJvYWNoIGlzIHRvIHJlLXJlYWQgbG8KPiA+ ID4gYWZ0ZXIgZGV0ZWN0aW5nIHRoZSBjaGFuZ2UsIG5vdCBmYWJyaWNhdGUgYSB2YWx1ZS4KPiA+ ID4KPiA+ID4gMi4gTXVsdGlwbGUgb3ZlcmZsb3dzOiBUaGlzIGFzc3VtZXMgYXQgbW9zdCBvbmUg b3ZlcmZsb3cgb2NjdXJzCj4gPiA+IGJldHdlZW4gcmVhZHMuIElmIHR3byBvdmVyZmxvd3MgaGFw cGVuIChlLmcuLCBkdWUgdG8gaW50ZXJydXB0Cj4gPiA+IGluamVjdGlvbiksIGhpKysgd2lsbCBw cm9kdWNlIGFuIGluY29ycmVjdCByZXN1bHQsIHNpbGVudGx5IGNvcnJ1cHRpbmcKPiA+ID4gdGhl IGNvdW50ZXIgdmFsdWUuCj4gPiA+Cj4gPiA+IE5lZ2xpZ2libGUgYmVuZWZpdDogaGkgY2hhbmdp bmcgYmV0d2VlbiByZWFkcyBpcyBhbiBleHRyZW1lbHkgcmFyZQo+ID4gPiBldmVudC4gT3B0aW1p emluZyBhd2F5IHRoZSByZXRyeSBsb29wIGZvciBzdWNoIGEgcmFyZSBjYXNlIHByb3ZpZGVzIG5v Cj4gPiA+IG1lYW5pbmdmdWwgcGVyZm9ybWFuY2UgZ2Fpbi4gQW5kIGlmIGhpIG5ldmVyIHN0YWJp bGl6ZXMsIHRoYXQKPiA+ID4gaW5kaWNhdGVzIGEgaGFyZHdhcmUgZmFpbHVyZSDigJQgaW4gd2hp Y2ggY2FzZSBoYW5naW5nIGluIHRoZSByZXRyeSBsb29wCj4gPiA+IGlzIGFjdHVhbGx5IHRoZSBt b3JlIGFwcHJvcHJpYXRlIGJlaGF2aW9yLCBhcyBpdCBtYWtlcyB0aGUgZmFpbHVyZQo+ID4gPiB2 aXNpYmxlIHJhdGhlciB0aGFuIHNpbGVudGx5IHByb2R1Y2luZyBnYXJiYWdlIHZhbHVlcy4KPiA+ ID4KPiA+ID4gVGhlIGhpZ2gtbG93LWhpZ2ggZG8td2hpbGUgcmV0cnkgc3RyYXRlZ3kgZXhpc3Rz IHByZWNpc2VseSB0byBoYW5kbGUKPiA+ID4gdGhlc2UgY2FzZXMgY29ycmVjdGx5LiBJIGRvbid0 IHRoaW5rIHRoaXMgcHJvcG9zZWQgc2VxdWVuY2UgaXMgYSB2YWxpZAo+ID4gPiByZXBsYWNlbWVu dC4KPiA+ID4gIAo+ID4KPiA+IFRoZSBwb2ludCBpcyB0aGF0IGlmIHRoZSB2YWx1ZSBpcyBhbiBp bmNyZW1lbnRpbmcgY291bnRlciAob2Ygc29tZSBmb3JtKQo+ID4gdGhlbiB0aGUgdmFsdWUgaXMg c3RhbGUgYnkgdGhlIHRpbWUgdGhlIHJlYWRpbmcgc2VxdWVuY2UgY29tcGxldGVzLgo+ID4gU28g YWxsIHRoZSBjb2RlIGNhbiBiZSBhc3N1bWVkIHRvIGRvIGlzIHJldHVybiBhIHZhbHVlIHRoZSBj b3VudGVyIGhhZAo+ID4gc29tZXRpbWUgYmV0d2VlbiB3aGVuIHRoZSBjb2RlIHN0YXJ0ZWQgYW5k IHdoZW4gaXQgZmluaXNoZWQuCj4gPiBJZiBoaSBjaGFuZ2VzIHRoZW4gaGkrMTowIG11c3QgaGF2 ZSBoYXBwZW5lZCB3aGlsZSB0aGUgY29kZSB3YXMgcnVubmluZwo+ID4gc28gaXQgaXMgYSBzYWZl IHJldHVybiB2YWx1ZS4gIAo+IFlvdSdyZSByaWdodCDigJQgKGhpICsgMSk6MCBpcyBlbm91Z2gg Zm9yIGhpLWxvLWhpLiBUaGFuayB5b3UgZm9yCj4gc3RpY2tpbmcgdG8geW91ciBwb2ludDsgaXQg aGVscGVkIG1lIHRoaW5rIG1vcmUgY2FyZWZ1bGx5IGFuZAo+IHVuZGVyc3RhbmQgdGhlIHN1YnRs ZXR5LgoKRG9uJ3Qgd29ycnksIEknbGwgaGF2ZSB3cml0dGVuIHRoZSBsb29wIGluIHRoZSBwYXN0 LgpQcm9iYWJseSBiZXN0IGlzIHJlYWQgb2xkX2hpLWxvLWhpIHRoZW4gaWYgKGhpICE9IG9sZF9o aSkgbG8gPSAwCgoJRGF2aWQKCj4gCj4gPgo+ID4gSXQgaXMgbGlrZWx5IHRoYXQgdGhlIHJlYWRz IGFyZSBhbHNvIG11Y2ggc2xvd2VyIHRoYW4gbWVtb3J5IHJlYWRzLgo+ID4gSWYgaGkgY2hhbmdl cyByZWxhdGl2ZWx5IGluZnJlcXVlbnRseSAoY29tcGFyZWQgdG8gdGhlIG51bWJlciBvZiByZWFk cykKPiA+IGl0IG1heSBiZSB3b3J0aCBzYXZpbmcgdGhlIHByZXZpb3VzbHkgcmVhZCB2YWx1ZSBh bmQgYXZvaWRpbmcgdGhlIHNlY29uZAo+ID4gcmVhZCBvZiBoaSBpZiBpdCBpcyB0aGUgc2FtZSBh cyB0aGUgcHJldmlvdXMgcmVhZCBoaSBhbmQgbG8gaGFzIGdvdCBsYXJnZXIuICAKPiAKPiAKPiAt LQo+IEJlc3QgUmVnYXJkcwo+ICBHdW8gUmVuCgoKX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX18KbGludXgtcmlzY3YgbWFpbGluZyBsaXN0CmxpbnV4LXJpc2N2 QGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9s aXN0aW5mby9saW51eC1yaXNjdgo=