From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id F1E841F30BB for ; Mon, 15 Sep 2025 09:13:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757927616; cv=none; b=V/w0PYO5CPq6dFquFvEzBaooR6IUSNA7syyeszivr7FABZE2j43W6/bl2j4qttAxpFyYGdnom6W6HD3LSL22YDKs1gun79RCH9Drc3LeGmk35tQyLXnMa5YKMk6L3wV1cg4hf+s2J6awOCJXSBBRLLDYrSWJRAI9VTjbf59gOZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757927616; c=relaxed/simple; bh=NtcqAVPtebwVePikKYuDoVB0ug1k1jHfCkmM7NepnwM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ghQe957PAdTjxDkh6CgGqbqykSEHCrJk5Tz1FwawRGjXA3sLX2FdBOVLHtyHBNbFsJCvmj7NNqCSxcndaO4JH+859eiDUlARFxb9WCUGZQo/Xs5BTuuw6HrfpFxjvEx6UFdhjUry3kcOyQkK6BdWCdDS0HnhTyKRXHotmnN47hc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E468B1424; Mon, 15 Sep 2025 02:13:24 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 177063F694; Mon, 15 Sep 2025 02:13:30 -0700 (PDT) Message-ID: <5d30d737-945f-4524-81ac-12ff03edca6c@arm.com> Date: Mon, 15 Sep 2025 10:13:29 +0100 Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] KVM: arm64: Fix debug checking for np-guests using huge mappings To: Vincent Donnefort Cc: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, james.morse@arm.com, tabba@google.com, Quentin Perret , Ryan Roberts , stable@vger.kernel.org References: <20250815162655.121108-1-ben.horgan@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/18/25 14:03, Vincent Donnefort wrote: > Thanks for the fix! > > On Fri, Aug 15, 2025 at 05:26:55PM +0100, Ben Horgan wrote: >> When running with transparent huge pages and CONFIG_NVHE_EL2_DEBUG then >> the debug checking in assert_host_shared_guest() fails on the launch of an >> np-guest. This WARN_ON() causes a panic and generates the stack below. >> >> In __pkvm_host_relax_perms_guest() the debug checking assumes the mapping >> is a single page but it may be a block map. Update the checking so that >> the size is not checked and just assumes the correct size. >> >> While we're here make the same fix in __pkvm_host_mkyoung_guest(). >> >> Info: # lkvm run -k /share/arch/arm64/boot/Image -m 704 -c 8 --name guest-128 >> Info: Removed ghost socket file "/.lkvm//guest-128.sock". >> [ 1406.521757] kvm [141]: nVHE hyp BUG at: arch/arm64/kvm/hyp/nvhe/mem_protect.c:1088! >> [ 1406.521804] kvm [141]: nVHE call trace: >> [ 1406.521828] kvm [141]: [] __kvm_nvhe_hyp_panic+0xb4/0xe8 >> [ 1406.521946] kvm [141]: [] __kvm_nvhe_assert_host_shared_guest+0xb0/0x10c >> [ 1406.522049] kvm [141]: [] __kvm_nvhe___pkvm_host_relax_perms_guest+0x48/0x104 >> [ 1406.522157] kvm [141]: [] __kvm_nvhe_handle___pkvm_host_relax_perms_guest+0x64/0x7c >> [ 1406.522250] kvm [141]: [] __kvm_nvhe_handle_trap+0x8c/0x1a8 >> [ 1406.522333] kvm [141]: [] __kvm_nvhe___skip_pauth_save+0x4/0x4 >> [ 1406.522454] kvm [141]: ---[ end nVHE call trace ]--- >> [ 1406.522477] kvm [141]: Hyp Offset: 0xfffece8013600000 >> [ 1406.522554] Kernel panic - not syncing: HYP panic: >> [ 1406.522554] PS:834003c9 PC:0000b1806db6d170 ESR:00000000f2000800 >> [ 1406.522554] FAR:ffff8000804be420 HPFAR:0000000000804be0 PAR:0000000000000000 >> [ 1406.522554] VCPU:0000000000000000 >> [ 1406.523337] CPU: 3 UID: 0 PID: 141 Comm: kvm-vcpu-0 Not tainted 6.16.0-rc7 #97 PREEMPT >> [ 1406.523485] Hardware name: FVP Base RevC (DT) >> [ 1406.523566] Call trace: >> [ 1406.523629] show_stack+0x18/0x24 (C) >> [ 1406.523753] dump_stack_lvl+0xd4/0x108 >> [ 1406.523899] dump_stack+0x18/0x24 >> [ 1406.524040] panic+0x3d8/0x448 >> [ 1406.524184] nvhe_hyp_panic_handler+0x10c/0x23c >> [ 1406.524325] kvm_handle_guest_abort+0x68c/0x109c >> [ 1406.524500] handle_exit+0x60/0x17c >> [ 1406.524630] kvm_arch_vcpu_ioctl_run+0x2e0/0x8c0 >> [ 1406.524794] kvm_vcpu_ioctl+0x1a8/0x9cc >> [ 1406.524919] __arm64_sys_ioctl+0xac/0x104 >> [ 1406.525067] invoke_syscall+0x48/0x10c >> [ 1406.525189] el0_svc_common.constprop.0+0x40/0xe0 >> [ 1406.525322] do_el0_svc+0x1c/0x28 >> [ 1406.525441] el0_svc+0x38/0x120 >> [ 1406.525588] el0t_64_sync_handler+0x10c/0x138 >> [ 1406.525750] el0t_64_sync+0x1ac/0x1b0 >> [ 1406.525876] SMP: stopping secondary CPUs >> [ 1406.525965] Kernel Offset: disabled >> [ 1406.526032] CPU features: 0x0000,00000080,8e134ca1,9446773f >> [ 1406.526130] Memory Limit: none >> [ 1406.959099] ---[ end Kernel panic - not syncing: HYP panic: >> [ 1406.959099] PS:834003c9 PC:0000b1806db6d170 ESR:00000000f2000800 >> [ 1406.959099] FAR:ffff8000804be420 HPFAR:0000000000804be0 PAR:0000000000000000 >> [ 1406.959099] VCPU:0000000000000000 ] >> >> Signed-off-by: Ben Horgan >> Fixes: db14091d8f75 ("KVM: arm64: Stage-2 huge mappings for np-guests") > > Not sure if it really matters but it's more about fixing f28f1d02f4ea (KVM: arm64: Add a range > to __pkvm_host_unshare_guest()) which introduced the check size != > kvm_granule_size(). Even though this is noop until db14091d8f75 Happy to update the Fixes tag with whatever is required. I was in two minds but opted for db14091d8f75 as that's where this starts to make a functional difference. > >> Cc: Vincent Donnefort >> Cc: Quentin Perret >> Cc: Ryan Roberts >> Cc: stable@vger.kernel.org > > Reviewed-by: Vincent Donnefort Thanks! Ben