From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.212 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793088721; b=wIHDVvSZmHkWqgcEgN62GdiO2a7FuHJjKLNQoSeaPvTRCn/04oclvaZUST2+Z2iq/BXY OBcHAUcAniCAUJE2rc19YTHgUYjy6Gaq8LioWG3ddSnMj4M6c7+HOT7byOwaYVrHKgcpT Q+7LLf2IaszsZTnLZWrwRDCH1XUJwN99zl2YnRaBJRZ5qqdYrYBz24Kr980xr5m7WHhoX NV8CgtQnxKtKVOp9K9A1a5oja3IHdKZjmGBmAjoK0k0C8UIimnSoCCUo/6L8Xw9/2Hkxa sH/Gc2Eohr4+8TlXfDfUwMuqof0RBg5lCL4KWj/d/T9mv0ez+oKHSltNHj8tEipc1+w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793088721; 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:MIME-Version:Content-Transfer-Encoding; bh=gb5sZs9kXKkHxMOBK0QCN7nKSbVD+3tuMPiUXhvbYWs=; b=ZSY2wuE8mMzxlRQXcTjUZpOWzf9SWdvKrRQD+hn9i22a9oo86aBgl1iBFL8n6qcYpI0f o2Ogn8I9MbW6EIrcjKkCMD7c44BuiD3cw0bLzX8BnVm3JcNeqn8fdR5RSXwqX+TSTgwlb kNvAVKu+sMjJkABIzF4ZsKOtN2IhachlAZBvVrTFLvWjj2DgMeJ4/PSfUIf6CAiC89xNA 8ZrLc5dmdQvDNSVYLp5e7pmti80ggqYoTYgyc/4zT64yvXHogXswXy6PITD1BocSuudwC kCp1benpFeQrPCk1NgSDM6991rH6ghPQ8OZdIuWInlD6Hhu5syJ0INHlhDsePsz/9wg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; arc=none smtp.remote-ip=91.218.175.212 Received: from mta0.migadu.com (out-212.mta0.migadu.com [91.218.175.212]) (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 3D644606A31B for ; Tue, 27 Oct 2026 08:11:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3D644606A31B 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 X-Envelope-To: kvmarm@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=uPm1bCuVoiN/lEjit+HbKmRBz2Yja0dVUN8FPqoeyWI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793088712; v=1; x=1793693512; b=U0BJUmhX6RzNk2/1qkmWnQdb3QryqZz51xgBbvnMpozZvRbiaxWB2hkdQ53sMVYEDPg7u+Cg YqMPfztZI0Y8rZdq9z+651ka5O8LUIvsiXN3dfQe5V4FBJlC2sv1ty+cL9uBOmba9HluKY/CZ7B MmXHxSp6221CY4ky4tZmTbHE= X-Envelope-To: kvmarm@lists.linux.dev Received: by smtp.migadu.com with ESMTPS id 45e916e20e21a3dd; Tue, 27 Oct 2026 08:11:52 +0000 X-Mizu-Trace-ID: 45e916e20e21a3dd X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Vincent Donnefort , kernel-team@android.com, linux-kernel@vger.kernel.org, Oculytic , Fuad Tabba Subject: [PATCH 0/3] KVM: arm64: Fix PMU handling in pKVM Date: Tue, 27 Oct 2026 08:11:44 +0000 Message-ID: <20261027081147.498183-1-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi folks, Two fixes and a hardening patch for PMU handling in pKVM, as one series [1]. The first is Vincent's rework of his HPMN fix. It supersedes his earlier posting [2]. Rather than read nr_event_counters through a different accessor, the host now copies the hypervisor's kvm_host_data before it's deprivileged, so host_data_ptr() returns what was set up at init. Otherwise, HPMN is 0 and a non-protected guest's event counters don't count. The second is the non-protected half of Oliver's patch from 2024 [3]. It passes the host's PMU events to the hyp vCPU of a non-protected guest, whose counters otherwise all read 0. The third covers the protected half. It stops the host's counters while a protected guest runs, so the host can't count the guest's cycles and events. Side channels are outside pKVM's threat model, so it carries no Fixes: tag. Based on kvmarm/next (dd0bc00e3e920). Cheers, /fuad [1] https://lore.kernel.org/all/86bj8kzix4.wl-maz@kernel.org/ [2] https://lore.kernel.org/all/20261023092007.3918848-1-vdonnefort@google.com/ [3] https://lore.kernel.org/all/20240305184840.636212-2-oliver.upton@linux.dev/ Fuad Tabba (1): KVM: arm64: Disable host PMU counters for protected guests Oliver Upton (1): KVM: arm64: Pass the PMU events to the hyp vCPU of non-protected guests Vincent Donnefort (1): KVM: arm64: Synchronise kvm_host_data before host deprivileging arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/debug.c | 4 +++- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 11 +++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 24 ++++++++++++++++++++++++ arch/arm64/kvm/pkvm.c | 6 ++++++ 5 files changed, 45 insertions(+), 1 deletion(-) base-commit: dd0bc00e3e9201fd49b62ff9cc07890c89003afe -- 2.47.3