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X-CSE-ConnectionGUID: pK8pCB3DS/iONQcoCEvRVg== X-CSE-MsgGUID: 1JakyOXxSpW+DXyDjwmmjw== X-IronPort-AV: E=McAfee;i="6800,10657,11719"; a="84414264" X-IronPort-AV: E=Sophos;i="6.21,324,1763452800"; d="scan'208";a="84414264" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2026 08:03:05 -0800 X-CSE-ConnectionGUID: h3BYdirGTOWuy2hNindZrA== X-CSE-MsgGUID: fAv0+3Q2ScSxmU7e3iJ16A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,324,1763452800"; d="scan'208";a="218329616" Received: from aschende-mobl.amr.corp.intel.com (HELO [10.125.108.205]) ([10.125.108.205]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Mar 2026 08:03:02 -0800 Message-ID: Date: Wed, 4 Mar 2026 08:03:08 -0800 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/7] x86/sev: add support for RMPOPT instruction To: Andrew Cooper Cc: Ashish.Kalra@amd.com, KPrateek.Nayak@amd.com, Michael.Roth@amd.com, Nathan.Fontenot@amd.com, Tycho.Andersen@amd.com, aik@amd.com, ardb@kernel.org, babu.moger@amd.com, bp@alien8.de, darwi@linutronix.de, dave.hansen@linux.intel.com, davem@davemloft.net, dyoung@redhat.com, herbert@gondor.apana.org.au, hpa@zytor.com, jackyli@google.com, jacobhxu@google.com, john.allen@amd.com, kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, nikunj@amd.com, pawan.kumar.gupta@linux.intel.com, pbonzini@redhat.com, peterz@infradead.org, pgonda@google.com, rientjes@google.com, seanjc@google.com, tglx@kernel.org, thomas.lendacky@amd.com, x86@kernel.org, xin@zytor.com References: <4ec520a1-68c7-4833-9e8f-edc610e5fdfa@citrix.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/4/26 07:56, Andrew Cooper wrote: > Logic asking hardware to optimise a 1G region because of no guest memory > should at least WARN() if hardware comes back and says "well hang on now..." It would be _nice_ to have a system where we can do a WARN(). But for something that's just a lowly optimization, I'd rather that RMPOPT lose the occasional race with a shared=>private conversion than have it take a lock and _block_ those conversions.