From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) (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 D68403E0094 for ; Wed, 19 Aug 2026 22:42:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787179383; cv=none; b=uSBykFWiRKyLBCWo8bAOBcpJGvd7KAWFwMJabn5nfBdeOisp0ExVIVb6gdsD2K2m4+MWpeamWTmCKhx3ADS9kbPZFKLVdXhXR3JRzpIgmfOFlanTrdJ/AYLYuU7bii9wvzwKnO8pi1L1VwuSybAeuqX84h8LuoUYgveYLT/9qt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787179383; c=relaxed/simple; bh=TBv4jWE24nFMwbwZRdR3u9uJWahJa5hxuvryb+jc+e8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=XQ8j68PSAOM0HBQ1rtfMy075G2/VkzzSZrbekr5Wfbg30j9JQHFtTOupYOio3xquqAl3ush1d1nutuWuMzhZ/IT3Mdkt6EYQvG2UE/PTxoPcnT6eP+iZEzh2OI29P+/5PUNDXNnbwUm0JbxA8adcBy1h5b6Fu3Xzf3QsvyrQvO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=MymcRbzy; arc=none smtp.client-ip=209.85.221.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MymcRbzy" Received: by mail-wr1-f45.google.com with SMTP id ffacd0b85a97d-47f84023916so1453678f8f.3 for ; Wed, 19 Aug 2026 15:42:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787179377; x=1787784177; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=vhLrSGY9svoYEa5H9hIeWUA3Z0wbe2vysdY+foWNbO8=; b=MymcRbzyCI9qU5cS+KQodr96iPszMfIwjMEtwHevceflmQzNARRkl0BQtuZyvfXyJi EYAaN362VjwkpytwHe581RA9LpPSI29/NMPpa9hoNHNKdSIg+VuQgT6FSDV4hgAB9nje 9zp6FEp8dMNMl+/Y7Rfuuhke8mINnRAH6NigNS625u/zPZZTfEo+DqNDXBSTWLlT8H+e zlp1KMav5uC/unz0nEfVJbb6bX9knAiilENtOq2Xjt86xEClNDDHoNafMmNO5dpbx0Be KRx0aQ1uw8pLlNfhj/TsOfiYnQAGwrOKLILlmSN/Pj9ecKaycXBSA00GKR6gIJaAAJOK /gdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787179377; x=1787784177; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=vhLrSGY9svoYEa5H9hIeWUA3Z0wbe2vysdY+foWNbO8=; b=C+b9DSt31+lWo+Pr5yTpijF7iOEzzocI+DWXeA2AaBXgF4E07RydTcLqloWRSw5fpz oPKvZ87F9YYMkxAaA9L3tKReA6sjxZ9X2unEuaAWdetilQRkyOSx4iceCtDNUXvcHvy4 OJZ11BSaCtVzsRpcezD6bmkSe3SdmugNtNqUXLOt8cMPImGfxJUKLiK9FpYojgCXIOTM wF/x2l1JYrUuDGnzrg3BZwSodjk6CsDgD7n8Z21RE8MsQn4zeYNGOxJIVdxpXyn6zsd8 2m7OsZtWxgZVuLHiA+tZwpxkKXizMYAXBMM+8UhD08Mg18wczvXZCMbAqlCZpKMvApBW /k2g== X-Forwarded-Encrypted: i=1; AHgh+RodIJnXFVN02MmdR03z6gf4QJVstJI14X1CsqXEumT64Wj888V0Dr5kMvQhCMNEmmR9/yE2Aw3U4lMde6M=@vger.kernel.org X-Gm-Message-State: AFuF++n68SwCBEmiDcGayDKD2ts81PMuszw2XHgta9Jp8byLrNHQhy8g JcOGNRRuioSI4groKUyIV90JUaLxFFhCu9UAJIY3+l86ijGPiaE0xCpL X-Gm-Gg: AR+sD10nwd7pyP/O/HMaFdidVdLF3ECOLT3neadvDOt3wxlumWE4FhxtybIoMhEtJdJ Kzs9lT1MzJqg/flx0XmOct5tDEUY74yPnafDO9uSK+6WxaaiEpG23GcnA58+6lXGx1TVqCnjPIm WvgrnVfVOfnQ7mN6mDqsRaV7WZwDj52NhXhzflkgo3BwyhZ/fVo3fs8kqJyPTXkDwhiAK+/pLQs ldoL357cbCoGsKk7cejs3qDVgq17elUZb3BDS5+ZIj1YpGN6Ex+3Oz79X/5CHztJ4oGjAKwfHsN yMoteIMZQaKvxRUwLhm7m9v/4KSwxiKgS0/mpo1tusU3POsn7IX+JqHuC9zcftqHZDs/LtuBhrI 2aCkv/0ASQ0hoqRA9ir7WWMy8OnVcVWkUHLMcVhgBcv7t5b1AwMwh9AiKDqszK1a76ehJ5Bwn8z VGsxWVRRF1eh7IX+FGp8zuCxvdxks37qr04sMs7aMolof1djUgmCtAJVjm6U+7biik7UkbiPim5 3VJHyUzGS2QpDwzZIokNR6F/P2dzBSKUGQv62c5IPMuiKdzH7NgYJC8hNuSR2ec4Mr4NwRRaeBL EIGeDg3YZzFFSgF01qzeYCSu6oFmRgjnOTIbgXzAp2Bi0D5m2nDTZysPFV69Z61qyhGC X-Received: by 2002:a05:6000:41de:b0:482:a36c:a5e1 with SMTP id ffacd0b85a97d-482b1e875b8mr15751227f8f.1.1787179376510; Wed, 19 Aug 2026 15:42:56 -0700 (PDT) Received: from localhost.localdomain (dynamic-2a02-3100-ae9e-1d01-58d3-443d-4fa6-01cd.310.pool.telefonica.de. [2a02:3100:ae9e:1d01:58d3:443d:4fa6:1cd]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482b1450e61sm8553317f8f.13.2026.08.19.15.42.54 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 19 Aug 2026 15:42:55 -0700 (PDT) From: Karl Mehltretter To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev Cc: Karl Mehltretter , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Paolo Bonzini , Shuah Khan , Eric Auger , Christoffer Dall , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v2 0/5] KVM: arm64: fix VGICv3 redistributor rollback Date: Thu, 20 Aug 2026 00:42:24 +0200 Message-Id: <20260819224229.82948-1-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit A failed REDIST_REGION write can unregister redistributor iodevs while leaving their cached vCPU assignments and free_index values intact. A retry then skips those assignments and succeeds with redistributors missing from the MMIO bus. Patches 1 and 2 fix VGICv3 redistributor failure handling. Patch 3 cleans up redistributor teardown. Patches 4 and 5 extend the KVM selftest infrastructure and add regression coverage. Patch 1 reserves the current vCPU's region slot before registering its iodev and releases the assignment if registration fails. This keeps free_index consistent with the cached assignments. Patch 2 uses the same cleanup during redistributor unregistration, allowing the existing rollback to reset the vCPUs processed before the failure. Patch 3 unregisters redistributors before freeing their regions and removes the region destructor's now-redundant vCPU scan. It is not required by the first two patches. Patch 4 lets the common VGIC setup helper select the guest entry point. Patch 5 adds a regression test that rejects an overlapping region, retries at a valid address, and then accesses all four redistributors. It exercises the failed region update fixed by patch 2. The MMIO bus registration failure handled by patch 1 is not fault-injected. Testing: built the patched kernel and selftest in an arm64 Linux Docker container with GCC 13.3.0. The selftest passed under QEMU 11.0.2 TCG with -machine virt,virtualization=on,gic-version=3 and -cpu max. The same selftest against the exact unpatched base failed with: Unexpected MMIO exit at 0x8030008 --- Changes since RFC: - Reset all redistributor assignments after a failed region update. - Split MMIO bus registration failure, region rollback, and teardown cleanup into separate patches. - Split the selftest infrastructure change from the regression test and check all four redistributors after retry. - Rebase onto the current kvmarm/next. Previous version: RFC: https://lore.kernel.org/r/cover.1786344511.git.kmehltretter@gmail.com Karl Mehltretter (5): KVM: arm64: vgic-v3: Undo assignment on iodev registration failure KVM: arm64: vgic-v3: Reset assignments after failed region setup KVM: arm64: vgic-v3: Unregister redistributors before freeing regions KVM: arm64: selftests: Pass guest code to vm_gic_create_with_vcpus() KVM: arm64: selftests: Test VGICv3 redistributor region retry arch/arm64/kvm/vgic/vgic-init.c | 11 +- arch/arm64/kvm/vgic/vgic-mmio-v3.c | 33 ++--- tools/testing/selftests/kvm/arm64/vgic_init.c | 117 ++++++++++++++++-- 3 files changed, 134 insertions(+), 27 deletions(-) base-commit: 57e7cf13ac26bf1a3dba6cfa601f7b2481811575 -- 2.39.5 (Apple Git-154)