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[37.24.206.209]) by smtp.gmail.com with ESMTPSA id xe3-20020a170907318300b00a471481ef3csm8659545ejb.124.2024.04.04.01.11.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 04 Apr 2024 01:11:16 -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: e9305879-f25a-11ee-afe5-a90da7624cb6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1712218276; x=1712823076; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from:references:cc :to:content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=pKh7Eu7TVgDxfeBSJtuFzVDUSdL1UAZsb7MOD/RFW9I=; b=bVWt04nT7vUaYE4Bq6sX5udxGy4sdrWlwT0MGG9mJDzxwNLPq6kHctHZtkqOGT5MfT 2TCQ7podbO2Bv3J9Mlz7CD7+V/6zAcLbmfeqsAvJDttbWj0Hchq0BU0Jx36n9EcY4OBO xeVl6Lhr4WQe1RKkWSVpupENfyAaCNMXZYBotw0/TkQxpG9wGS0UIjGVA6GfQQ9heu4l MuQLz8nMUaBM2PQr5nZEVKjh9I020+QYmQCl0rff2DivyjD9O0EF+SsJatHRi5St+fxd YQ1MRR02E5T0GrpqruuwArkwgUCS4JSD6gNTGfqripfghsKaZXDuCL8YjO+7IV5smitW ib2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712218276; x=1712823076; h=content-transfer-encoding:in-reply-to:autocrypt:from:references:cc :to:content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=pKh7Eu7TVgDxfeBSJtuFzVDUSdL1UAZsb7MOD/RFW9I=; b=VstBwvI4bnVcgFEHtF6/+zMliqFY9eTFy6/pnxHZnPlBCkGyGdMS/54LkP2R6BmbLg q2LIngNaQx50wl9Lecs7SwZznxWn88JoENjLwWn+kUNTEs/DqclUkd1pnZ7t+m/vGvKZ NevyFLK2di/3hP5KJeBjOlMXL29jEMwl+fS7lVjk/qa50brjuFIpvJAGpuSGvtYTHRRV 2GUjsun6KQWIf7KhZu2xr93qTY+1bhin93TO2NK3bND1b0hkBXVh2aW+iyD5ocr83MPA IJJpYiB8zMqvK8+sx/Yq8sVX4iv0r9PxIZPYpHb+NRSXyP5JAnwNZXX1fyjg8daakAgo 3asA== X-Forwarded-Encrypted: i=1; AJvYcCUB9nUh/CyaRKdWMglC5CyMQg2Jmq3gU3EUoSmk8RgeXsOO/k88DWCurT59G0Z/N5wjQmpLI1OoZKpZSP1OvNJW7NMjL2YyHILMaVJywzA= X-Gm-Message-State: AOJu0YzV7YkpTxNofAYQbJtG25xm9YU/1yCwxXzVRLib4wtJV0zyudqJ 8CwqPEv1/Tvy6txu/Xkm6rDPT4avSUkNv3wUI9rEz7haYm3i5vs85yen8RyT4A== X-Google-Smtp-Source: AGHT+IGqylbQPD+BfjzLoS3D8QdndY7FhmGtJB7hdYKKAcd0E/bufPm0NohLSrss3OfzxQO+fNA31w== X-Received: by 2002:a17:907:9487:b0:a4e:2cd6:8ac2 with SMTP id dm7-20020a170907948700b00a4e2cd68ac2mr1350990ejc.56.1712218276588; Thu, 04 Apr 2024 01:11:16 -0700 (PDT) Message-ID: Date: Thu, 4 Apr 2024 10:11:15 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] Revert "evtchn: refuse EVTCHNOP_status for Xen-bound event channels" Content-Language: en-US To: "Daniel P. Smith" Cc: George Dunlap , Stefano Stabellini , Julien Grall , Xen-devel , Andrew Cooper References: <20240402170612.2477791-1-andrew.cooper3@citrix.com> <11957460-0b2b-432d-ad92-38350306c9ff@suse.com> <3aa0893b-7efd-4ca1-a405-e897edc7402f@apertussolutions.com> <3b8ec757-d2f3-4143-a843-de8c6d51944d@suse.com> 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: 7bit On 03.04.2024 15:31, Daniel P. Smith wrote: > On 4/3/24 07:54, Jan Beulich wrote: >> On 03.04.2024 13:50, Daniel P. Smith wrote: >>> On 4/3/24 02:52, Jan Beulich wrote: >>>> On 03.04.2024 08:16, Jan Beulich wrote: >>>>> On 02.04.2024 19:06, Andrew Cooper wrote: >>>>>> Whether to return information about a xen-owned evtchn is a matter of policy, >>>>>> and it's not acceptable to short circuit the XSM on the matter. >>>>> >>>>> I can certainly accept this as one possible view point. As in so many cases >>>>> I'm afraid I dislike you putting it as if it was the only possible one. >>>> >>>> Further to this: Is there even a way to express the same denial in XSM? >>>> alloc_unbound_xen_event_channel() doesn't specifically "mark" such a >>>> channel, and (yes, it could in principle be open-coded in Flask code) >>>> consumer_is_xen() is private to event_channel.c. I also dare to question >>>> whether in SILO mode status information like this should be available. >>> >>> To build on the previous response: if the natural failure return value >>> is -EACCESS in response to a domain resource access attempt, then the >>> probability is extremely high that it should be implemented under a XSM >>> hook and not hard-coded into the resource logic. >> >> Possibly. But first of all - could you answer the earlier question I raised? > > Don't need to, this change subverts/violates the access control > framework. If the desire is to make this access decision for the > default/dummy policy, then codify it there. Otherwise I will be ack'ing > this change since it is access control and falls under the purview of XSM. If Xen internals like this are to be exposable (and controlled by XSM), why would other Xen internals not similarly be (optionally) exposed? Further, since above you referred to EACCES being what XSM is supposed to control: xsm_default_action() used EPERM, and (presumably; too long ago) EACCES was chosen here precisely to make it not look like an XSM surrogate. Jan