From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 5BF6E1C0DE6 for ; Thu, 30 May 2024 12:17:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717071463; cv=none; b=TEJ2XIz4KQb4URymOv9RyzqHLSwVXNfZSEmpAiE9aseBGg+mHp/3EBwlcLwK0XhBBAVO5wo19XQDa753fXfQYoWEpH8fLTwYjenFeRFvRiM9nmm/2zXoC+8YUjEgbAGNbzcpdkK1jR3tzN353y70rlGiG95bf5Kbhmjh322tDNk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717071463; c=relaxed/simple; bh=V5hI7KMkzgVk/ALuPDZUKKRsX7oat0m5/GaY+dT+YqQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WIMq4a53N3sNnB0qhWZJatcBdL6DrVW6bvc21/zvfWTgJKvMO9miwnftrvYAnDsABh7x/RHgwv3xCnofXfpIzeRBB7pW3/x1IMxBbAPVneJyqTQ0/iv30+uXk7OTCnEm8Hzr41OuaTsZoUP0wI7lhAFLIZEDJgqnKmFIWR8S8Uw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LoAwMDxV; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LoAwMDxV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1717071460; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UMT67zC+fbo2iQB9ZfpmsekE+SDPWB6XReNKWdjTg/c=; b=LoAwMDxVHuQKj/WF4jyOSj/tx2lnxHbSKNZT0LpG5s9N1EiAeaBjln1b4wsQlZvraXCwhx 9X9vMLJQ45ZOSNG+OvBSb7FdaR+Y/wf79kRCymuJguZwMwdo8CwIKAtIHAquEIaD/Agd8I 8l0Fiwbvh8zaf1o1GfDy2BbOOaNowxk= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-10-E5N7WMQENl2LN2lpIVVX-A-1; Thu, 30 May 2024 08:17:37 -0400 X-MC-Unique: E5N7WMQENl2LN2lpIVVX-A-1 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-35dcbb5c163so284336f8f.1 for ; Thu, 30 May 2024 05:17:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1717071456; x=1717676256; h=content-transfer-encoding:in-reply-to: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=UMT67zC+fbo2iQB9ZfpmsekE+SDPWB6XReNKWdjTg/c=; b=wOGHtgjSQvb5PhE86RYqDoKSu6fEqcNqYclVg3SxGJPBWOQsoPxHlv2S7N3rKr7weP x6kONSY5vpGr4Ib/v/XYClRwG0kh4sxXvqxUOzJj1zUR4iduTN3YDKz3bUy1J5Vx0bZR EKMaymdN3GfovNQXu6o7BNQQfZ2AUiGHFinN6l+Aq4aWAWp4C/qIOhK29vT0ylr/pD5z PqzXsVjXcD2f3Cg7ta1muRrRZyEh0onCUgNS192hmaXYdFy6IM4Uzo2ADwKVBzqsPEBL TUJLb8ge02lvUIKuT9KHEVsXR1iUuE8duSAJsV+0IM1m+qw4rtNCT+53idzpib4RXlmO VFKw== X-Forwarded-Encrypted: i=1; AJvYcCURWJ5cmkWFxLPm4N6+SELJorpZs3Vt2DDs5BgkICOXwCV6OxFSpj4dxv69hqIbpZtX8KtN14fsnP50hlVsneO/V+Xt7+D0Y/BVzpIM X-Gm-Message-State: AOJu0YwFuIKttrjgmR+RcC5siDzd+4FiK3iFGUxU6NuiffCOvelbaz86 0WXUmSMddnV+s8LAvoux6wBCxdY+i+i+A3ozhJ7Y8Z69N2NTQGuxWmhqb7JXWLI+rkC3DWng4JZ aXsJAO5sA+VuQV4hEB5wd05wKjaKf9Henk+J/dPx1AHfNBsOR1K5r9u3Dk+9R9Q== X-Received: by 2002:adf:f989:0:b0:354:f90c:63dd with SMTP id ffacd0b85a97d-35dc00369c3mr1370856f8f.0.1717071456028; Thu, 30 May 2024 05:17:36 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGCeaFufh+CD65vlqUrpverwcUO7ViCXf3RbM0I0lK+Q3pHJBTo8PrCVYwi3ANZO5WJqWE20A== X-Received: by 2002:adf:f989:0:b0:354:f90c:63dd with SMTP id ffacd0b85a97d-35dc00369c3mr1370836f8f.0.1717071455558; Thu, 30 May 2024 05:17:35 -0700 (PDT) Received: from ?IPV6:2a01:e0a:59e:9d80:527b:9dff:feef:3874? ([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-35dca3dbee6sm1356852f8f.53.2024.05.30.05.17.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 30 May 2024 05:17:35 -0700 (PDT) Message-ID: <897ea2fa-838a-4b33-8434-dba5dddaf9ca@redhat.com> Date: Thu, 30 May 2024 14:17:33 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/6] KVM: arm64: maintain per VM value for CTR_EL0 Content-Language: en-US To: Sebastian Ott Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Catalin Marinas , Will Deacon References: <20240514072252.5657-1-sebott@redhat.com> <20240514072252.5657-3-sebott@redhat.com> <90e53cc7-039f-5abc-f94c-cf53a1602a2a@redhat.com> <2dcfc174-9384-4746-833d-1442bcfb6d11@redhat.com> From: Eric Auger In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/30/24 13:24, Sebastian Ott wrote: > On Wed, 29 May 2024, Eric Auger wrote: >> On 5/29/24 17:51, Sebastian Ott wrote: >>> On Wed, 29 May 2024, Eric Auger wrote: >>>>> @@ -3557,6 +3557,13 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu) >>>>>      struct kvm *kvm = vcpu->kvm; >>>>>      unsigned long i; >>>>> >>>>> +    if (!kvm_vcpu_initialized(vcpu)) >>>> at this stage of the reading, why is the above check needed? >>> >>> To make sure that a later call to this function doesn't overwrite >>> the value provided by userspace. (See e016333745c "KVM: arm64: Only >>> reset vCPU-scoped feature ID regs once"). >> but isn't it overwritten through the .reset=reset_ctr() that is >> populated in next patch? > > No, this is done via reset_vcpu_ftr_id_reg() and also guarded by > kvm_vcpu_initialized(). OK thanks. Eric > > Sebastian