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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5a30a4d6e67sm6041345a12.17.2024.07.22.05.09.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Jul 2024 05:09:16 -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: 37e2d922-4823-11ef-bbfe-fd08da9f4363 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1721650156; x=1722254956; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=Q1ODGjjIkswPcEwduhZfJL5a1ukg2QuJ74+piOzsw6g=; b=UrEaZXM3DBsq0Zmvlw1szr1skh4c2JnwFrg5Tj7hDa06ULwSzWgzA98yCHep2IgV6c auqR0JdoD0C1xbgL4b8towDp9SQ1rI7lhY7pyE0rZpokolLhnSl7ZwPy4EekETj1/7uT i8F88cfwiod7udYzREf0Inh51X7kRYoUMO/XYdgIrxU/vBRJKEypHjRyBKS9iQi4ZCs0 IhsnId6BjBL8eiqdXbeV+m1TDUWKviLYDbJ8ml8nZa8nANmJsAJYaPg86Q9tCRfonG/U lmlTUl4tg/BKRn7JjFKorXpDbnfzP4oiOAlgGTzN8VKEJvfHuylIcPq+8QQoq4xoAp3T vGDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721650156; x=1722254956; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Q1ODGjjIkswPcEwduhZfJL5a1ukg2QuJ74+piOzsw6g=; b=aFMPyDpjzerGUkCfZXplhrW04x7WMOfLEZfv9nzVftSB/wE8Ec0hkz5FEfuIaULSjY 5eZDzzT1Vq37/60XcN+0hsOHU7j1zrxC8VTGqMl88DEDfjrG461nkH9zgJJzrkFFLWZx ugIGv63v9PmftTjDeZejXEQGSy6j4QdIu3G8KZhHEBmYnfFbUiZlbfGqQMja5h7UlQmu Qgb08+OO2KNroAI0VRfQuZdEjVqn6LyRLqEHtTzj+XQVliwDRzgs4RUapGdesOreNfGz 7rK7X3lJbn/dAvMVt9IRVgQVTUfOnXr5U+jx9UXA1THLgGiI+m/peCqio5RWsd093pgn z17Q== X-Forwarded-Encrypted: i=1; AJvYcCW1B5e5X8kY2KPQfL8wAfH9rw3B1LjzSvbhUXQtX1C9ONvpul0bdccfZMfyJ2e+id2We6LKZ5HQscKfwW/o5e4dOffXCfo8nNDsXeh3RCM= X-Gm-Message-State: AOJu0YyHbeObbPqlGpwzjDldnOURCuaINbKDWQ6FsQWTbRivvWckQeYH Odq5rSSNO6yYzvED5PVfOpGuSfJNHL7ydTEKIZus2NKQ78Pyerrr+ULEnNw/hw== X-Google-Smtp-Source: AGHT+IEqEm3kMlveM6LuDWgYK7mEv9UNyWyWbDjpC5W4BIcpLCu501EmdQ6HypF4tqpQ7YiD/hg0xw== X-Received: by 2002:a50:d514:0:b0:5a2:a808:a2e0 with SMTP id 4fb4d7f45d1cf-5a478b64758mr3867686a12.4.1721650156570; Mon, 22 Jul 2024 05:09:16 -0700 (PDT) Message-ID: Date: Mon, 22 Jul 2024 14:09:15 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 2/3] x86/mm: add API for marking only part of a MMIO page read only To: =?UTF-8?Q?Marek_Marczykowski-G=C3=B3recki?= Cc: Andrew Cooper , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , xen-devel@lists.xenproject.org References: Content-Language: en-US From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 19.07.2024 04:33, Marek Marczykowski-Górecki wrote: > @@ -4910,6 +4921,254 @@ long arch_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg) > return rc; > } > > +static void __iomem *subpage_mmio_find_page(mfn_t mfn) > +{ > + struct subpage_ro_range *entry; With the function returning void*, my first reaction was to ask why this isn't pointer-to-const. Yet then ... > + list_for_each_entry(entry, &subpage_ro_ranges, list) > + if ( mfn_eq(entry->mfn, mfn) ) > + return entry; ... you're actually returning entry here, just with its type zapped for no apparent reason. I also question the __iomem in the return type. > +static int __init subpage_mmio_ro_add_page( > + mfn_t mfn, > + unsigned int offset_s, > + unsigned int offset_e) > +{ > + struct subpage_ro_range *entry = NULL, *iter; > + unsigned int i; > + > + entry = subpage_mmio_find_page(mfn); > + if ( !entry ) > + { > + /* iter == NULL marks it was a newly allocated entry */ > + iter = NULL; Yet you don't use "iter" for other purposes anymore. I think the variable wants renaming and shrinking to e.g. a simple bool. > + entry = xzalloc(struct subpage_ro_range); > + if ( !entry ) > + return -ENOMEM; > + entry->mfn = mfn; > + } > + > + for ( i = offset_s; i <= offset_e; i += MMIO_RO_SUBPAGE_GRAN ) > + { > + bool oldbit = __test_and_set_bit(i / MMIO_RO_SUBPAGE_GRAN, > + entry->ro_elems); Nit: Indentation looks to be off by 1 here. > + ASSERT(!oldbit); > + } > + > + if ( !iter ) > + list_add(&entry->list, &subpage_ro_ranges); What's wrong with doing this right in the earlier conditional? > +int __init subpage_mmio_ro_add( > + paddr_t start, > + size_t size) > +{ > + mfn_t mfn_start = maddr_to_mfn(start); > + paddr_t end = start + size - 1; > + mfn_t mfn_end = maddr_to_mfn(end); > + unsigned int offset_end = 0; > + int rc; > + bool subpage_start, subpage_end; > + > + ASSERT(IS_ALIGNED(start, MMIO_RO_SUBPAGE_GRAN)); > + ASSERT(IS_ALIGNED(size, MMIO_RO_SUBPAGE_GRAN)); > + if ( !IS_ALIGNED(size, MMIO_RO_SUBPAGE_GRAN) ) > + return -EINVAL; I think I had asked before: Why is misaligned size something that wants a release build fallback to the assertion, but not misaligned start? > +static void subpage_mmio_write_emulate( > + mfn_t mfn, > + unsigned int offset, > + const void *data, > + unsigned int len) > +{ > + struct subpage_ro_range *entry; > + volatile void __iomem *addr; > + > + entry = subpage_mmio_find_page(mfn); > + if ( !entry ) > + /* Do not print message for pages without any writable parts. */ > + return; > + > + if ( test_bit(offset / MMIO_RO_SUBPAGE_GRAN, entry->ro_elems) ) > + { > +write_ignored: Nit: Like you have it further up, labels indented by at least one blank please. Jan