From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.67 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793606333; b=12FAjc8iNxy8ExydBA7WBVN1HQ3IQhLgNtIUk6g9OW2dNZ3DDl/I/ebuhbtPH4Ginuf8 BiEUz8b8rfhp2dlsEV/UW4qNS/A4Ij+o2sdhi9zVLJYD1Q29dQJUWgueqZhbdKeZ9WWq1 wN6jR78WlYn+RgnFr+ezVGvi/JUD/ljjNR+P8x/noJgOty0265uB+AcbFBBKwmSwg/bJ5 Xb10eYGvrDVu4Rwl/HGCJnpxjx1ycezmO3nNp+Q1x7jgHgbPMm1OGzFkxyZSPLCT2Pxa1 fYWThxmGfGODbVreirfci8hV22ansrZH/79ILJBDh+50vdKktPpl9KFB+6+j7KvX1Bg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793606333; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=I7f0XyCAtF4SJfvjHPyOeR1juZYlK47QDPUr9ArN18s=; b=JoZLcud7TBV46w8J7IP5s3yyYO6ihZX05/Z0Qnr1DzmgZh2JUCSV7pg/xFQbDmqUFsuD JN/6g+Vt9/KcVAOJ4ZwvKx6Aw1kfeG3AVKzrdf9CdBhm8chAzUEpapE2kMLpulcuyH1+I D1b348aXTzMlv8Y3GtbGWBoAvCF0hZpdvmvbxhOSYqRMVEnVkWah8NWy6ZZ4b7cJsmgQ5 i5NUMsTlaTyb4yws+Ka9a6UA8v4QmZeEeugzKCbDHMen8sRtuMGTr7CmUIgfvggcNTfQ2 nsyP1WRpXxqD1MOyomJ1aVqx3ax2OxI4v2sEJKyoMMEg3QBIvyNAzRJLq7lq6D0PfWw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ogl8CBtQ; arc=none smtp.remote-ip=91.218.175.67 Received: from mta0.migadu.com (out-67.mta0.migadu.com [91.218.175.67]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 94481606A32D for ; Mon, 2 Nov 2026 07:58:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 94481606A32D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ogl8CBtQ X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=0wwKFnAfKLxHm3MqsSLnib+x1Cbbb0RE6cyNuCZw7gg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793606328; v=1; x=1794211128; b=ogl8CBtQDjMx17gldrzG8y9aQpsv613GYEwNn1rJXC+6g/+opPkIIcn+HlXnAavrY1GAUOPR txvgIyi154ghhKYCU0qOvD37Z8I+Q68/aAi2YXxkuHE8YpTvtAEVvcChEiA6LpGxcNy4ifYtDgx 6Gx1AIx4F8D+VlBhLhO16xlA= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 9c4dd2f3ef011e26; Mon, 02 Nov 2026 07:58:48 +0000 X-Mizu-Trace-ID: 9c4dd2f3ef011e26 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Will Deacon , Lorenzo Stoakes , Jack Thomson , Congkai Tan , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Fuad Tabba Subject: [PATCH v4 1/2] KVM: arm64: Clear the VM's feature bitmap when kvm_setup_vcpu() fails Date: Mon, 2 Nov 2026 07:58:42 +0000 Message-ID: <20261102075843.2556018-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261102075843.2556018-1-fuad.tabba@linux.dev> References: <20261102075843.2556018-1-fuad.tabba@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit KVM_ARM_VCPU_INIT records the requested features in the VM-wide bitmap before kvm_setup_vcpu() runs, and leaves them there when setup fails (e.g., HAS_EL2_E2H0 on a host without FEAT_NV1). The PMU attributes read that bitmap before the vCPU is initialized, so after such a failure with PMU_V3 requested, KVM_SET_DEVICE_ATTR on the PMU group no longer returns -ENODEV. Until an INIT has succeeded, every INIT that gets past the feature checks rewrites the bitmap. After that, kvm_vcpu_init_changed() requires the requested features to match it, so the copy is a no-op. Clear the bitmap on failure while KVM_ARCH_FLAG_VCPU_FEATURES_CONFIGURED is clear. Fixes: 427733579744e ("KVM: arm64: Select default PMU in KVM_ARM_VCPU_INIT handler") Suggested-by: Oliver Upton Reviewed-by: Lorenzo Stoakes (ARM) Signed-off-by: Fuad Tabba --- arch/arm64/kvm/arm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 157bf4b812020..3e91e01b032c4 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1856,8 +1856,13 @@ static int __kvm_vcpu_set_target(struct kvm_vcpu *vcpu, bitmap_copy(kvm->arch.vcpu_features, &features, KVM_VCPU_MAX_FEATURES); ret = kvm_setup_vcpu(vcpu); - if (ret) + if (ret) { + /* Clear the bitmap if setup fails on the first vCPU to be initialized. */ + if (!test_bit(KVM_ARCH_FLAG_VCPU_FEATURES_CONFIGURED, &kvm->arch.flags)) + bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES); + goto out_unlock; + } /* Now we know what it is, we can reset it. */ kvm_reset_vcpu(vcpu); -- 2.47.3