From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f43.google.com (mail-wm1-f43.google.com [209.85.128.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BA432C1B4 for ; Mon, 2 Sep 2024 06:11:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725257470; cv=none; b=uvDpHI1WLeS76yZUop06uNjqDVsUDj2MeHILQPXN5NRXdpMgh3AGRJPoq9Bi/bkwA70QbGui5yp3N3hS8UtlA5nmwe2C04xnPJruS9J2WUXjQJvrnuKcj6jBih0dAUSr6pbNXfmn5IKIz1LuVHZ75HpY7c7pPlwlPvOiMuAWB/I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725257470; c=relaxed/simple; bh=MlYWtDA0Q5mTKyOcOuik7KuozIlUKzVC9dFl1KRxWgI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=q9rM6X5S/s+D9L831t9emQ/ee7YUfBIcx6CE/RXucf/WLBuVBwyzqMNQSj2IAwW/cQ19LlOSbJTj/O1Hz17IAP16/OSUyBqCyfRX7HKf948lKNb9B4dalyoiKO7MXOpye3JjDQQa83kvY6f4sJERIpBzUEGRlo1NFZqqiZqFPEo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=TY/a26vJ; arc=none smtp.client-ip=209.85.128.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="TY/a26vJ" Received: by mail-wm1-f43.google.com with SMTP id 5b1f17b1804b1-427fc9834deso55925e9.0 for ; Sun, 01 Sep 2024 23:11:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1725257467; x=1725862267; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Qt/pdhmIWCaDpBvzCVUeydNCVwTTuBE7DiHS/h0oVUg=; b=TY/a26vJTPdgrPHuQRReT4E3rpQAWhtb0x0J/GXHFdsKt9tx2DD3wm1myozq/Q8yor 71stO1wEUQmLTzYBEtGx3f0vnsBVeZCGvzQ3l6G8k4w15QWLQcmpXBjmiyTWyuqv/Wc9 zNycTPmaT2LjnfuDsjvQEy3l/V+1TZ0MuGG7n/soS7Yk3hcr9TWh63/kcYi72Eefuifx J/OVzPi0k5farhL5DE0npdzuHHMSllsPzJYPlRXz/3IMv4y21v3CABNxr7JmT0dgd+XC EsaliyBefVSIlGSF3puldrfUulYWm/MCIGb3Jx3HUC9o5LBOJMbWuvV1IABcxjj2nAHQ DWMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725257467; x=1725862267; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Qt/pdhmIWCaDpBvzCVUeydNCVwTTuBE7DiHS/h0oVUg=; b=LCNB6UD9hd0RIS72A+uC+jPcsbOumnPM0C/O4LBiXMLzzZAr620SNa9XQrciac9igy U25npJK40BXteTga6l802Gy+5UCIpIMW6Rdee0xfk3R2KBuCbLznk5Yzb4nlj+WS9vgu vaM5Nb0YaM3HuluvTs+BAUF91yXJvpP4P0nla+iLUPZp+K8Hw5atUIFXIBseFpFamsWm aCuILvhN6tWLOjIgGDFuqDkpRRgHdTYrAUmhBEs/b4AZnX4tEFdqKCMpT/hUosij3H4T xeQaGZeg9HAL6jx+qP7pVjpuQ9eoXSXtzZBkNy00n1h0o3HlxUXCfFpLYSDSOIicLh3F j/eg== X-Forwarded-Encrypted: i=1; AJvYcCU1q8V7C77xhjYcXOPOfelUQdJxdtSf+2+8yVltyzRz//gakE3H86TPq7FxSU44ktYJqub5WHQ=@lists.linux.dev X-Gm-Message-State: AOJu0YwdYN714hpd8k4cebuqmOmrzawpCXg2bh0hxagL9EZ/gJVLVFja 7A/1zbAE88d69fXqlCSEMvZ8qRqMBcxBJEWUuC2mPt8QRpA8t8QXnL0cC3bXtg== X-Google-Smtp-Source: AGHT+IHKtVCpGX9bH5U9KFiXdwjXiY8dpd2rUZf/jifFQW9iyvTCQi9VEs44YJiTljvwor2vaDBCZQ== X-Received: by 2002:a05:600c:34c9:b0:42b:892a:333b with SMTP id 5b1f17b1804b1-42c2e54127emr1907065e9.2.1725257466373; Sun, 01 Sep 2024 23:11:06 -0700 (PDT) Received: from google.com (44.232.78.34.bc.googleusercontent.com. [34.78.232.44]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-374b67ff88dsm7477026f8f.26.2024.09.01.23.11.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Sep 2024 23:11:06 -0700 (PDT) Date: Mon, 2 Sep 2024 06:11:04 +0000 From: Sebastian Ene To: Marc Zyngier Cc: akpm@linux-foundation.org, alexghiti@rivosinc.com, ankita@nvidia.com, ardb@kernel.org, catalin.marinas@arm.com, christophe.leroy@csgroup.eu, james.morse@arm.com, vdonnefort@google.com, mark.rutland@arm.com, oliver.upton@linux.dev, rananta@google.com, ryan.roberts@arm.com, shahuang@redhat.com, suzuki.poulose@arm.com, will@kernel.org, yuzenghui@huawei.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v9 0/5] arm64: ptdump: View the second stage page-tables Message-ID: References: <20240827084549.45731-1-sebastianene@google.com> <864j72vzmw.wl-maz@kernel.org> <8634mmvyx0.wl-maz@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8634mmvyx0.wl-maz@kernel.org> On Fri, Aug 30, 2024 at 04:00:11PM +0100, Marc Zyngier wrote: > On Fri, 30 Aug 2024 15:44:39 +0100, > Marc Zyngier wrote: Hello Marc, > > > > Hi Seb, > > [...] > > > I've been giving this a go on my test systems with 16k pages, and it > > doesn't really work as advertised: > > > > root@babette:/sys/kernel/debug/kvm# cat 2573-13/stage2_* > > 2 > > ---[ Guest IPA ]--- > > 0x0000000000000000-0x0000000008000000 128M > > 0x0000000008000000-0x00000000090a0000 17024K 3 > > 0x00000000090a0000-0x00000000090a4000 16K 3 R W X AF > > 0x00000000090a4000-0x000000000a000000 15728K 3 > > > > Only 16kB mapped? This is a full Linux guest running the Debian > > installer, and just the kernel is about 20MB (the VM has 4GB of RAM, > > and is using QEMU as the VMM) > > > > So clearly something isn't playing as expected. Also, this '128M' > > without a level being displayed makes me wonder. It is probably the > > QEMU flash, but then the rest of the addresses don't make much sense > > (RAM on QEMU is at 1GB, not at 128MB. > > > > On another system with kvmtool, I get something similar: > > > > root@duodenum:/home/maz# cat /sys/kernel/debug/kvm/*/stage2_* > > 2 > > ---[ Guest IPA ]--- > > 0x0000000000000000-0x0000000001020000 16512K 3 > > 0x0000000001020000-0x0000000001024000 16K 3 R W X AF > > 0x0000000001024000-0x0000000002000000 16240K 3 > > > > and kvmtool places the RAM at 2GB. Clearly not what we're seeing here. > > > > Could you please verify this? Ughh, this doesn't look right. I will give it a spin with a different granule, thanks for bringing me to attention. I will look first at mm/ptdump.c if it works as intended. > > For the record, on a 4kB host, I get much more plausible results: > > root@big-leg-emma:/home/maz# cat /sys/kernel/debug/kvm/632-12/stage2_* > 3 > ---[ Guest IPA ]--- > 0x0000000000000000-0x0000000000200000 2M 2 R AF BLK > 0x0000000000200000-0x0000000040000000 1022M 2 > 0x0000000040000000-0x0000000040200000 2M 2 R W X AF BLK > 0x0000000040200000-0x0000000044000000 62M 2 > 0x0000000044000000-0x0000000044200000 2M 2 R W X AF BLK > 0x0000000044200000-0x0000000047600000 52M 2 > 0x0000000047600000-0x0000000047800000 2M 2 R W AF BLK > 0x0000000047800000-0x0000000047e00000 6M 2 R W X AF BLK > 0x0000000047e00000-0x0000000048000000 2M 2 R W AF BLK > 0x0000000048000000-0x00000000b9c00000 1820M 2 > 0x00000000b9c00000-0x00000000b9e00000 2M 2 R W X AF BLK > 0x00000000b9e00000-0x00000000bb800000 26M 2 > 0x00000000bb800000-0x00000000bba00000 2M 2 R W X AF BLK > 0x00000000bba00000-0x00000000bbe00000 4M 2 R W AF BLK > 0x00000000bbe00000-0x00000000bc200000 4M 2 R W X AF BLK > 0x00000000bc200000-0x00000000bc800000 6M 2 R W AF BLK > 0x00000000bc800000-0x00000000be400000 28M 2 > 0x00000000be400000-0x00000000bf800000 20M 2 R W X AF BLK > 0x00000000bf800000-0x00000000bfe00000 6M 2 R W AF BLK > 0x00000000bfe00000-0x00000000c0000000 2M 2 R W X AF BLK > > So 16kB is the one that needs investigating, and I strongly suspect > that 64kB is in the same boat... > > Thanks, > > M. (signing off for the day) > Thanks, Sebastian > -- > Without deviation from the norm, progress is not possible.