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Sat, 5 Sep 2026 00:45:09 +0000 (UTC) Date: Fri, 4 Sep 2026 17:45:05 -0700 From: Borislav Petkov To: Reinette Chatre Cc: Ben Horgan , x86@kernel.org, james.morse@arm.com, fenghuay@nvidia.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, corbet@lwn.net, linux-doc@vger.kernel.org, dave.martin@arm.com Subject: Re: [PATCH v5 0/3] x86,fs/resctrl,arm_mpam: Factor MBA parse-time conversion to be per-arch Message-ID: <20260905004505.GAaptmEVxltONVfl2J@fat_crate.local> References: <20260709093111.367851-1-ben.horgan@arm.com> <165e7636-d7e9-4d16-aad1-657b4a9698d0@intel.com> <20260904033751.GCapo9D5ZZXWuQkIpc@fat_crate.local> <20260904173615.GOapsBjyiT7uXHd-Qc@fat_crate.local> <35ebb8d4-2ef0-4bc0-ac3f-afff0c95ae89@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <35ebb8d4-2ef0-4bc0-ac3f-afff0c95ae89@intel.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260904_174545_921082_EC2EA485 X-CRM114-Status: GOOD ( 12.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 04, 2026 at 02:15:08PM -0700, Reinette Chatre wrote: > Sashiko's second comment is about resctrl's existing (not introduced by this patch) > Intel specific enumeration being resilient against a hypervisor misconfiguration. > Thus far resctrl assumed the enumeration would return what the actual hardware > is known to support. > > Sashiko had similar "hypervisor misconfiguration" comments in response to another > resctrl series that already falls under the "cleanup" umbrella. It is not clear to > me how far resctrl needs to go to be resilient against hypervisor misconfiguration > but I can include needed validation addressing this report as part of [1]. I would always ask myself how realistic is the use case. Here, I'm thinking not that realistic unless you guys wanna support resctrl in a guest. Which would be weird, IMHO, because a guest can fake all kinds of hw so controlling resources of a fake hw is an exercise in futility. So might as well answer that Sashiko review comment with "thanks, but no thanks." :-) -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette