From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.236 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793185667; b=nnyfMUiJR25QnBSo76V3zNWsdv2EN/bNgTLQ6Q0oMmQQuDGouWjjhUxASRDQnorPYeeh DntOgmBVqFROeHaiGViNmFBnalBj8ge5+R88hb2tCIbCc0N252pLIyMJ/Dpr6tqOTswSZ 1Z4BmH3+Ci1Px9OxI/CoINNHqNsznDBUuUqV8oVm7mXLgPxKjcBjaeOSreUwy71eWl7ou kYKhllogDUEeDaCJjQHuB9iE06q3TOQ8VmJZslEs8LhxH6VOK9blKeYggOykkpI0OgCaS F4UVJtxaS10XT/wa4yZJddBLgqHXcMcrXXdwS5WFO4t/RGAote/WX5YACvaeZg3X6tw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793185667; 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=miIuE2N/e+SG7Kz34MMJd25ETZ3yxYFkA9Zemr87Wgo=; b=d8YE/77cD23ry5xKIhOZJsyTX/0LRi4coYSLjVUXXF+sNETWW5Hd3eQj+hspoEuLaMBv mfX+i5y6o6TNIuENmZBAMULdHVsVDBBdCTOCHbmvXagjlArQ2Ka6HIqjuroPhaCLPZTAq Q2vxKl8FZdCbULudAGJN3/T1+yVIGJ1H3pHmd++hXPLIdilnXGtI2Z6D8U9E8OjSuWyOD DUd7+PXXNhcdUeoXzHW0Zf9Jnvu/zp4CN5eI7l64HSp6OmJS6xAn3oSoxFkhGYHXi0zaL rIfxyhcS0BY1DLgCKpxCl/MM9kciXU6XlRhPS/NGXfq9KtOyJJnpT2ja21+mYzJGKfg== 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=JbcWMaMv; arc=none smtp.remote-ip=95.215.58.236 Received: from mta1.migadu.com (out-236.mta1.migadu.com [95.215.58.236]) (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 986F3606A31C for ; Wed, 28 Oct 2026 11:07:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 986F3606A31C 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=JbcWMaMv X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=Pg95Y+xFHx1ZIocuSPAyjynJpdUBiCDULSiHROnP0Os=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793185664; v=1; x=1793790464; b=JbcWMaMviRNJd8kBhaAtmLnWIDfterzdjIYllNK0xeavjxLbiYJigDFfLD4lnLenqGBmg2Lu 6yi6fwWuojUcQRLIJIfxP2O7WheAQYb7kHPt+Ckh2WrDB0scnRejCZqMW7mzMP7kVjq4rr2fNRI j9CMEK6tunROWqpFNsf898ik= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id e69cc8713850fd5b; Wed, 28 Oct 2026 11:07:44 +0000 X-Mizu-Trace-ID: e69cc8713850fd5b 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 v2 0/3] KVM: arm64: Fix PMU handling in pKVM Date: Wed, 28 Oct 2026 11:07:36 +0000 Message-ID: <20261028110739.2366566-1-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 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 Hi folks, Changes since v1 [1]: - Gate __pmu_stop_host_counters() on system_supports_pmuv3() rather than v1's per-CPU HAS_PMUV3 flag. (Marc) - Collected Vincent's Reviewed-by and Tested-by on patch 2. (thanks!) Two fixes and a hardening patch for PMU handling in pKVM, as one series [2]. The first is Vincent's rework of his HPMN fix. It supersedes his earlier posting [3]. Rather than read nr_event_counters through a different accessor, the host 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 [4]. 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/20261027081147.498183-1-fuad.tabba@linux.dev/ [2] https://lore.kernel.org/all/86bj8kzix4.wl-maz@kernel.org/ [3] https://lore.kernel.org/all/20261023092007.3918848-1-vdonnefort@google.com/ [4] 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/kvm/hyp/nvhe/hyp-main.c | 11 +++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 24 ++++++++++++++++++++++++ arch/arm64/kvm/pkvm.c | 6 ++++++ 3 files changed, 41 insertions(+) base-commit: dd0bc00e3e9201fd49b62ff9cc07890c89003afe -- 2.47.3