From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta1.migadu.com (out-172.mta1.migadu.com [95.215.58.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F36111DA55 for ; Thu, 11 Sep 2025 18:27:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757615269; cv=none; b=gnvP7z0DCEZvxOcXsGAmCfMk4AW20DNI4XWofEDM8sIZGDtt5sP+GEzN1IQoUpHA0Wtrz+8cylaejvUPpjntzy0Eet51YQbpG+EPLkwxQ9ijpsH1c1SU+Wda03ivBzYsFlaQ2fKz5Ls5LdkL2PqcR6vnTbnByr+5WfNdDKKpZkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757615269; c=relaxed/simple; bh=dMozuue/sJaEdI+2v0oGtDcTdVocJ4ZzaVwH4WcwWac=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Oh3Aj29sj+GbTYUA0qunGv6teQWlpvZPXCegxrN9KI3uAOrCbwH1fedZEmDOuTblGbf/Gztm/40yogYhupy9B68uP/i2Fz3NEc9UigJdIKjcdA56plgH9EPs6wCyXgcWa8Se6kDQVPYWcDybShqyjNimyrrXkyXvmBeLikLsPOs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=m66MoVbH; arc=none smtp.client-ip=95.215.58.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="m66MoVbH" Date: Thu, 11 Sep 2025 11:27:23 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1757615256; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1PEqqMkQCCsIIK80US5++EkJbtoh1psej63veCBFsh0=; b=m66MoVbHAakOQHxhknbRV0aEtrzLIl0zCY5MZnXw/n2GB/8mMD2z8KI6sr7j6Zg2VMz5fZ LrEYbqoS2fE1sJyLz+JwXmPOOsVm1xe52j/yNKp+vJUnkU92KRcLd/H0qB2d1zMQk7NV3/ 0LIJakGffNrD7vjzin8Tacb4DAiuocM= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Jack Thomson Cc: maz@kernel.org, pbonzini@redhat.com, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, isaku.yamahata@intel.com, roypat@amazon.co.uk, kalyazin@amazon.co.uk, jackabt@amazon.com Subject: Re: [PATCH 1/6] KVM: arm64: Add __gmem_abort and __user_mem_abort Message-ID: References: <20250911134648.58945-1-jackabt.amazon@gmail.com> <20250911134648.58945-2-jackabt.amazon@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250911134648.58945-2-jackabt.amazon@gmail.com> X-Migadu-Flow: FLOW_OUT Hi Jack, On Thu, Sep 11, 2025 at 02:46:43PM +0100, Jack Thomson wrote: > From: Jack Thomson > > Adding __gmem_abort and __user_mem_abort that preserve -EAGAIN results. > These will be used by the pre-fault implementation which needs to retry > on -EAGAIN. -EAGAIN is a pretty clear signal that another vCPU has faulted on this memory and is in the middle of installing a mapping. Why bother with retrying? If we conceptually treat this thing as a synthetic stage-2 abort then it should use the same EAGAIN handling as a literal stage-2 abort. Thanks, Oliver