From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.173 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793201522; b=XVgfHcNUF73LWP4E59lAuwqw6/FAx8T8jHeFKJt3vrXERJhshv4KlaV5PZUY6eCdH789 lgAq4IjWpnmqm9QibUlfzClIgXcXmBIWKRWA99fQMsJvWkhRiU20ORPtS6yInE6ibM4Yf fYhpBbig6OtRvqd06YIEhEMqHK3bdJBqeYtJsZ3zwni1sEtWLVEdBr+00/IOarYAhmgkA yjRgomzyGlBGtOesORbT0vPHXiyMWeWVEhjdLU3sClkB5zOd+YayWLvXjAZmOsdb/+r6t GLZjo8/6sZdoJNor2uYsHowDvHer+z1w09xKmcJ8sD+Elgec7O/r4UY6AdnqVsIHKeQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793201522; 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=/dqcNV2rxcj+H+N6V1Q7pF0i14uOvWt3XmYVtpF0Vwo=; b=OAv7EHlZ6ETHmXx71MxpWp9OHbFpbM2n/Vpas89+GnC4rGgkNF/XpSXZ7P3w0+NKTHWF H4jZib0pDEirT6UVDxAE37Y6Zmi7LSXEEvV7C2y92oBzqZUvUyn27ySoUhC8sb2y/VQZS 1O3TelSjN3tDhclwQ/guS01u2YtTaJG/onQSePhCXOn9FudDu11zaruKrN76/1G9ZDS4K SPgUZd1gUEr0QfUkXoVGVCMaZXCPczotoKp1QkWmwoQPBE3KE+YCYyPCDKn8sw2il94DT 6b1pLJl52WTLB59CLkQ3Y4FwjoDVkSQo0TtbhwYPfOIbh0j6hRkcKPxhNt2m4mm0K+g== 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=xb5nZuD2; arc=none smtp.remote-ip=95.215.58.173 Received: from mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 46416606A320 for ; Wed, 28 Oct 2026 15:32:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 46416606A320 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=xb5nZuD2 X-Envelope-To: kvmarm@lists.linux.dev DKIM-Signature: a=rsa-sha256; bh=hOfLyCvPxdoMK3iGT2snLIRtrBmcqixK3sf0MGFjqIg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793201519; v=1; x=1793806319; b=xb5nZuD2ABwyQl4nxMN0ZnFllS2AzPkEPZ1p+XokSb7KMe+6glcbj656ChKzAJ1H4nKWjJjU k14PTpdGt0A5O/E8UKJU0fWdmO0LePFN0l4knxy+yLIt6k+xuvLk/CPDzoQXH372GnlGCxJcnMJ h60bkJC3tNPpTOO/xUP6feeM= X-Envelope-To: kvmarm@lists.linux.dev Received: by smtp.migadu.com with ESMTPS id 3c4a590b27db9bbe; Wed, 28 Oct 2026 15:31:59 +0000 X-Mizu-Trace-ID: 3c4a590b27db9bbe 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 v3 1/3] KVM: arm64: Synchronise kvm_host_data before host deprivileging Date: Wed, 28 Oct 2026 15:31:50 +0000 Message-ID: <20261028153152.1740044-2-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261028153152.1740044-1-fuad.tabba@linux.dev> References: <20261028153152.1740044-1-fuad.tabba@linux.dev> 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 From: Vincent Donnefort When protected mode is enabled, the host is populating and reading the hypervisor copy of kvm_host_data until it is deprivileged. This is an issue for nr_event_counters which is only used by the host to populate mdcr_el2. After deprivileging, it is reading an uninitialised value and sets HPMN to 0, preventing programmable event counters from counting a non-protected guest. Before the host is entirely deprivileged, copy the entire kvm_host_data content from the hypervisor copy to the host-accessible one. Fixes: 2417218f2f23 ("KVM: arm64: Get rid of __kvm_get_mdcr_el2() and related warts") Signed-off-by: Vincent Donnefort Signed-off-by: Fuad Tabba --- arch/arm64/kvm/pkvm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 380dfb1db0be4..58190ff6723d6 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -316,6 +316,12 @@ static void __init _kvm_host_prot_finalize(void *arg) { int *err = arg; + /* + * After __pkvm_prot_finalize, access to the hypervisor copy of + * kvm_host_data is lost. Save it into the host-accessible version. + */ + *this_cpu_ptr(&kvm_host_data) = *this_cpu_ptr_nvhe_sym(kvm_host_data); + if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize))) WRITE_ONCE(*err, -EINVAL); } -- 2.47.3