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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-57cb741e6c8sm6463910a12.77.2024.06.17.06.43.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Jun 2024 06:43:21 -0700 (PDT) Message-ID: Date: Mon, 17 Jun 2024 15:43:20 +0200 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] iommu/xen: Add Xen PV-IOMMU driver To: Teddy Astie Cc: Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Joerg Roedel , Will Deacon , Robin Murphy , =?UTF-8?Q?Marek_Marczykowski-G=C3=B3recki?= , xen-devel@lists.xenproject.org, iommu@lists.linux.dev References: <8b0151a8-2293-409a-8469-d9e73cf561a3@suse.com> 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 17.06.2024 15:36, Teddy Astie wrote: > Le 13/06/2024 à 16:32, Jan Beulich a écrit : >> On 13.06.2024 15:50, Teddy Astie wrote: >>> @@ -214,6 +215,38 @@ struct xen_add_to_physmap_range { >>> }; >>> DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap_range); >>> >>> +/* >>> + * With some legacy devices, certain guest-physical addresses cannot safely >>> + * be used for other purposes, e.g. to map guest RAM. This hypercall >>> + * enumerates those regions so the toolstack can avoid using them. >>> + */ >>> +#define XENMEM_reserved_device_memory_map 27 >>> +struct xen_reserved_device_memory { >>> + xen_pfn_t start_pfn; >>> + xen_ulong_t nr_pages; >>> +}; >>> +DEFINE_GUEST_HANDLE_STRUCT(xen_reserved_device_memory); >>> + >>> +struct xen_reserved_device_memory_map { >>> +#define XENMEM_RDM_ALL 1 /* Request all regions (ignore dev union). */ >>> + /* IN */ >>> + uint32_t flags; >>> + /* >>> + * IN/OUT >>> + * >>> + * Gets set to the required number of entries when too low, >>> + * signaled by error code -ERANGE. >>> + */ >>> + unsigned int nr_entries; >>> + /* OUT */ >>> + GUEST_HANDLE(xen_reserved_device_memory) buffer; >>> + /* IN */ >>> + union { >>> + struct physdev_pci_device pci; >>> + } dev; >>> +}; >>> +DEFINE_GUEST_HANDLE_STRUCT(xen_reserved_device_memory_map); >> >> This is a tools-only (i.e. unstable) sub-function in Xen; even the comment >> at the top says "toolstack". It is therefore not suitable for use in a >> kernel. >> > IMO this comment actually describes how the toolstack uses the > hypercall, but I don't think it is actually reserved for toolstack use. Well, the canonical version of the header is quite explicit about this, by having the definition in a __XEN__ || __XEN_TOOLS__ section. > Or maybe we should allow the kernel to use this hypercall as well. That's an option to consider. Jan