From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7E9912D7DC8 for ; Sat, 4 Apr 2026 18:13:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775326416; cv=none; b=Uu6InqewMATKsktSPPdnLqbq/XKHuONHMlDcx6OM4pJIxrmX6VeOAORAWy/b1EGcaZmdUvDvLcYYhhj/hnC6sPNb6f2JWgxdtP+yYrtBcWDKy9aFy8aDP6DHA8ITod1coxjMtyWKaDgsqOKhQISZ8bviB1MiyVnXP/8WXyGUINk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775326416; c=relaxed/simple; bh=wjBG2dDvNOcl73t5Dsrip8H0/qPbPfDx7nYSPfXnK9U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UIwH7Y3dL+mCbfCjmm+Vx002Axr/e1KpuED0VPMN7OFtuEt3Mt+ZGQ8T21hQtq+hhmzHpBvkr2kA9FFp1qsbO1qrcgg6st8aQAWSaTS/fTbyMqQkMrAT/72TlOHNrKH9JfZ73tarYmQ73BK8bTg2rTt/SL8PyPVux71qYHsxa0U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b2pO4bdX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="b2pO4bdX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F32CC19424; Sat, 4 Apr 2026 18:13:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775326416; bh=wjBG2dDvNOcl73t5Dsrip8H0/qPbPfDx7nYSPfXnK9U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=b2pO4bdXXFL1yc84LWPwy/iQoPw+SE+ISHxp+wjlENH+6kkZcAGH7OWOaXKJVY+QS TMtj8hNKN9E/r/jOhU1ZRCwFGeC6xnxGAR80fbbJUUWI1JRMWSGlNJMaBsaW+bcdPk 7q1WL3opiHRdmO8kKVQG5Fw3MsbXpxu79A2wNOcgaamUMOb1eM+nNq7EuBDj1SRBb1 TS2ni3llMnn4kMlp4pgZKQcUC/jzbw8YsvtTSBTK7iRjCscWS/9VOtUOqnFUMsYl8X uwgEIo6k8mEpYIdphbHNKEPQHn4Urwq6oRrwjmzVfateMMrzrNkMSqU2dk9NvEtd+N evARPDS2MV6LA== Date: Sat, 4 Apr 2026 20:13:30 +0200 From: Nathan Chancellor To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Sascha Bischoff , Will Deacon , Catalin Marinas Subject: Re: [PATCH] KVM: arm64: Advertise ID_AA64PFR2_EL1.GCIE Message-ID: <20260404181330.GA3987102@ax162> References: <20260401170017.369529-1-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: <20260401170017.369529-1-maz@kernel.org> Hi Marc, On Wed, Apr 01, 2026 at 06:00:17PM +0100, Marc Zyngier wrote: > As we are missing ID_AA64PFR2_EL1.GCIE from the kernel feature set, > userspace cannot write ID_AA64PFR2_EL1 with GCIE set, even if we are > on a GICv5 host. > > Add the required field description. > > Signed-off-by: Marc Zyngier > --- > arch/arm64/kernel/cpufeature.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 32c2dbcc0c641..5bca6e064ca72 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -327,6 +327,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr2[] = { > ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_FPMR_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_MTEFAR_SHIFT, 4, ID_AA64PFR2_EL1_MTEFAR_NI), > ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_MTESTOREONLY_SHIFT, 4, ID_AA64PFR2_EL1_MTESTOREONLY_NI), > + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_GCIE_SHIFT, 4, ID_AA64PFR2_EL1_GCIE_NI), > ARM64_FTR_END, > }; > > -- > 2.47.3 > After this change in -next as commit 899ff451fcee ("KVM: arm64: Advertise ID_AA64PFR2_EL1.GCIE"), I am seeing a warning on boot in my simple QEMU boot tests. $ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux- mrproper virtconfig Image.gz $ curl -LSs https://github.com/ClangBuiltLinux/boot-utils/releases/download/20241120-044434/arm64-rootfs.cpio.zst | zstd -d >rootfs.cpio $ qemu-system-aarch64 \ -display none \ -nodefaults \ -machine virt,gic-version=max \ -append 'console=ttyAMA0 earlycon' \ -kernel arch/arm64/boot/Image.gz \ -initrd rootfs.cpio \ -cpu host \ -enable-kvm \ -m 1G \ -smp 8 \ -serial mon:stdio [ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x413fd0c1] [ 0.000000] Linux version 7.0.0-rc4-00058-g899ff451fcee (nathan@aadp) (aarch64-linux-gcc (GCC) 15.2.0, GNU ld (GNU Binutils) 2.45) #1 SMP PREEMPT Sat Apr 4 06:55:05 MST 2026 ... [ 0.000000] ------------[ cut here ]------------ [ 0.000000] SYS_ID_AA64PFR2_EL1 has feature overlap at shift 12 [ 0.000000] WARNING: arch/arm64/kernel/cpufeature.c:986 at init_cpu_features+0xbc/0x344, CPU#0: swapper/0 [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.0.0-rc4-00058-g899ff451fcee #1 PREEMPT [ 0.000000] Hardware name: linux,dummy-virt (DT) [ 0.000000] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.000000] pc : init_cpu_features+0xbc/0x344 [ 0.000000] lr : init_cpu_features+0xbc/0x344 [ 0.000000] sp : ffffcd0982373db0 [ 0.000000] x29: ffffcd0982373db0 x28: 0000000000000010 x27: ffffcd0981c63878 [ 0.000000] x26: 0000000000000018 x25: ffffcd0982013f38 x24: ffffcd0981c69068 [ 0.000000] x23: ffffcd0981c635f0 x22: ffffcd0982388640 x21: 0000000000000003 [ 0.000000] x20: 0000000000000017 x19: ffffcd09824c9308 x18: 000000000000000a [ 0.000000] x17: 5d305b203837205d x16: 305b203737205d30 x15: 0000000000000000 [ 0.000000] x14: 0000000000000000 x13: 3231207466696873 x12: 2074612070616c72 [ 0.000000] x11: 0000000000000058 x10: 0000000000000018 x9 : ffffcd0982396598 [ 0.000000] x8 : 0000000000057fa8 x7 : 000000000000002a x6 : ffffcd09823ee598 [ 0.000000] x5 : ffffcd09823ee598 x4 : 0000000000000000 x3 : 0000000000000000 [ 0.000000] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffcd09823852c0 [ 0.000000] Call trace: [ 0.000000] init_cpu_features+0xbc/0x344 (P) [ 0.000000] cpuinfo_store_boot_cpu+0x48/0x54 [ 0.000000] smp_prepare_boot_cpu+0x28/0x38 [ 0.000000] start_kernel+0x248/0x780 [ 0.000000] __primary_switched+0x88/0x90 [ 0.000000] ---[ end trace 0000000000000000 ]--- ... ``` Is this expected? I assume not, hence the report. If there is any information I can provide or patches I can test, I am more than happy to do so. Cheers, Nathan # bad: [2febe6e6ee6e34c7754eff3c4d81aa7b0dcb7979] Add linux-next specific files for 20260403 # good: [d8a9a4b11a137909e306e50346148fc5c3b63f9d] Merge tag 'v7.0-rc6-smb3-client-fix' of git://git.samba.org/sfrench/cifs-2.6 git bisect start 'origin/master' 'origin/stable' # bad: [dc9c72702de7e46679f8c2ab2175ab7070baa3ee] Merge branch 'main' of https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git git bisect bad dc9c72702de7e46679f8c2ab2175ab7070baa3ee # bad: [d5ea83fae6558b2431b022781f6ccb74d241b2bb] Merge branch 'for-next' of https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git git bisect bad d5ea83fae6558b2431b022781f6ccb74d241b2bb # bad: [d16ebd2d0dc90f1561d0a44a828db2c9148ad5f4] Merge branch 'for-next/perf' of https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git git bisect bad d16ebd2d0dc90f1561d0a44a828db2c9148ad5f4 # bad: [768784742008ccebbf3e88a26a6e9e6aad76dc8e] Merge branch 'timekeeping-next' of https://github.com/Rust-for-Linux/linux.git git bisect bad 768784742008ccebbf3e88a26a6e9e6aad76dc8e # good: [b671065be2bef906bb3e0c1bc7be4055e84ea1d3] Merge branch 'at91-fixes' of https://git.kernel.org/pub/scm/linux/kernel/git/at91/linux.git git bisect good b671065be2bef906bb3e0c1bc7be4055e84ea1d3 # bad: [bd1f7328e25426f08cafa8333293411788c7957b] Merge branch kvm-arm64/vgic-fixes-7.1 into kvmarm-master/next git bisect bad bd1f7328e25426f08cafa8333293411788c7957b # good: [1cd0bb0425594cea9baf862393a4ca9cc0c018a3] Merge branch kvm-arm64/pkvm-psci into kvmarm-master/next git bisect good 1cd0bb0425594cea9baf862393a4ca9cc0c018a3 # good: [bc20692f528b2ac8226bafe5b1db9a1f8be96dbf] KVM: arm64: Don't hold 'vm_table_lock' across guest page reclaim git bisect good bc20692f528b2ac8226bafe5b1db9a1f8be96dbf # good: [adb70b3a8b31e9eb05f2ec3c76d85f9a7a8c8cbc] KVM: arm64: Directly expose mapping prot and kill kvm_s2_fault git bisect good adb70b3a8b31e9eb05f2ec3c76d85f9a7a8c8cbc # good: [be46a408f376df31762e8a9914dc6d082755e686] KVM: arm64: Correctly plumb ID_AA64PFR2_EL1 into pkvm idreg handling git bisect good be46a408f376df31762e8a9914dc6d082755e686 # good: [33cdd7f8fa32c92317aa521bd6f407a3cba8474b] Merge branch kvm-arm64/spe-trbe-nvhe into kvmarm-master/next git bisect good 33cdd7f8fa32c92317aa521bd6f407a3cba8474b # good: [e54971a0468a8bc82b1976d5b010392d7cb689b9] Merge branch kvm-arm64/vgic-fixes-7.1 into kvmarm-master/next git bisect good e54971a0468a8bc82b1976d5b010392d7cb689b9 # bad: [899ff451fcee1289f3f37d061da66c3e38748a69] KVM: arm64: Advertise ID_AA64PFR2_EL1.GCIE git bisect bad 899ff451fcee1289f3f37d061da66c3e38748a69 # good: [9c1ac77ddfc90b6292ef63a4fa5ab6f9e4b29981] KVM: arm64: vgic-v5: Fold PPI state for all exposed PPIs git bisect good 9c1ac77ddfc90b6292ef63a4fa5ab6f9e4b29981 # first bad commit: [899ff451fcee1289f3f37d061da66c3e38748a69] KVM: arm64: Advertise ID_AA64PFR2_EL1.GCIE