From nobody Mon Feb 9 14:14:50 2026 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (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 AB36735971D for ; Sat, 31 Jan 2026 13:29:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866183; cv=none; b=Q0FpT2E65fkJqQ1pPS9g9UsmBLuHFPh/HEby9H1tUugHxULzChgZVYlexxhDXuVVL2RlndRysU4skgLbi2wxeLsg2SaZTGQkfZHgAdi6aDjqBpl/FgG+bS0pTI+Mcx8s4/doaRquDhTI5/G5qyJyuTJI9Ik24L672mpCKjbk3So= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866183; c=relaxed/simple; bh=fhPeQWVBSnCBrnALKVurTRUuPiSMZ+f8M8+cUOxcd9o=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=CM+3TVH9iXGm0wXq6Uup4xyhJNt+mg3UW1bTczgwCnkvJsvARUjBT52llKYQnJyyX0PkZ/9ryhG6C0qPCnqxIULxfhK69JetxoC1Ri+4z05NCbzngUmSUM5lQ39lE0ZwvwBL+2dXnVBL4xOdgzMT2EaQvbcOFF9YGloFn5mZVKg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=shR+yCPa; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="shR+yCPa" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-482d8e6e13aso15113295e9.3 for ; Sat, 31 Jan 2026 05:29:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769866180; x=1770470980; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=goZ+MaQKy7l7B7ncr3K66S9aihGDrIDC3mypa0RPtIo=; b=shR+yCPa5yAlvHuz8iMQb28m8bm+SbLvib+3DZAF1QqMQ9G3hA0pJ1JnjKX3gsps/B AiX0KEY4yih3k0Lqqugl23VheIWccwYTVd4bkMbfBfGEAUXtIQRPvluhe6LAfvCNTz1Q U4i72sPDOaFx1x3juNhgHIFnhS9BDWWTKAbDmFNk1EjlSez4cGVKzDWO2iDfjUml/Md6 zbwXj+2bH9ECyhpX0A51vB7Lzz7Gfat3JDLMYD9dQxNwcR8EoS9AO5sJsMX5TXF3v0t/ 9YSG+SSrbouSiMOcfLohk98g4gVcTiKC1cJSZxD+NFMZtgiXAvidSKN+8VddI7YhRv4m RuaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769866180; x=1770470980; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=goZ+MaQKy7l7B7ncr3K66S9aihGDrIDC3mypa0RPtIo=; b=FpJJ47W6eGJwkO21kvXhwsmg1NKU6nODX95ClP0u9ljcTWCARQk45KRsQMhIkDHUcB FMXu3qEoBEQNybmGn61jAR5TXRlBcsdLj5QkKfVXBLiS2vqhqMd7l3i9LMxmThQ2BIKK ouh9+pZpDaL5ibQokH/zj+3drtyefwla3VcEupU5x0IgwzHSYrvfrvOcQY5uU0e0Jexl wJ71I6ZkwQL9NZEHcL0QVUMDN+bCIybAZ1H+0G3fum5GGczPMRIq6CJ6j3KiZO76tr4C wFPqeVTuP+0L8tr1F8An/5JD+wHs5XxCTPtB7VZ4Nds+ReiKl8upseyLjNqaxlOLV5nA JIiw== X-Forwarded-Encrypted: i=1; AJvYcCVlU/YIjxcrBvc8OLn/rFRPsOw22lYJkxXcT0Lwc+f91GVMRzAyMDenxmNlX/02AyLUrf4v44Zgy7/eo2I=@vger.kernel.org X-Gm-Message-State: AOJu0Yxx5EZYO2dWUU2CHAlFg2HS64mZqlRPqoh3WdfpcaSPktMzYmre VKS7UcgsoPdUwk8A1UQXWWX9ZibDmU612lMABOMX167OWD25SnvThpV5yMOA9j4Xajxsw4Yq4MZ ngilylxaCfeWEn6LJpp8AMQ== X-Received: from wmz6.prod.google.com ([2002:a05:600c:6b66:b0:480:1b84:b6e]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1da8:b0:480:3a71:92b2 with SMTP id 5b1f17b1804b1-482db498227mr71271215e9.26.1769866180081; Sat, 31 Jan 2026 05:29:40 -0800 (PST) Date: Sat, 31 Jan 2026 13:28:38 +0000 In-Reply-To: <20260131132848.254084-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260131132848.254084-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.rc1.225.gd81095ad13-goog Message-ID: <20260131132848.254084-21-vdonnefort@google.com> Subject: [PATCH v11 20/30] KVM: arm64: Add clock support to nVHE/pKVM hyp From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In preparation for supporting tracing from the nVHE hyp, add support to generate timestamps with a clock fed by the CNTCVT counter. The clock can be kept in sync with the kernel's by updating the slope values. This will be done later. As current we do only create a trace clock, make the whole support dependent on the upcoming CONFIG_NVHE_EL2_TRACING. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/kvm/hyp/include/nvhe/clock.h b/arch/arm64/kvm/hyp/i= nclude/nvhe/clock.h new file mode 100644 index 000000000000..9f429f5c0664 --- /dev/null +++ b/arch/arm64/kvm/hyp/include/nvhe/clock.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ARM64_KVM_HYP_NVHE_CLOCK_H +#define __ARM64_KVM_HYP_NVHE_CLOCK_H +#include + +#include + +#ifdef CONFIG_NVHE_EL2_TRACING +void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc); +u64 trace_clock(void); +#else +static inline void +trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { } +static inline u64 trace_clock(void) { return 0; } +#endif +#endif diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Mak= efile index a244ec25f8c5..8dc95257c291 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -17,7 +17,7 @@ ccflags-y +=3D -fno-stack-protector \ hostprogs :=3D gen-hyprel HOST_EXTRACFLAGS +=3D -I$(objtree)/include =20 -lib-objs :=3D clear_page.o copy_page.o memcpy.o memset.o +lib-objs :=3D clear_page.o copy_page.o memcpy.o memset.o tishift.o lib-objs :=3D $(addprefix ../../../lib/, $(lib-objs)) =20 CFLAGS_switch.nvhe.o +=3D -Wno-override-init @@ -29,6 +29,7 @@ hyp-obj-y +=3D ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cp= uif-proxy.o ../entry.o \ ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o hyp-obj-y +=3D ../../../kernel/smccc-call.o hyp-obj-$(CONFIG_LIST_HARDENED) +=3D list_debug.o +hyp-obj-$(CONFIG_NVHE_EL2_TRACING) +=3D clock.o hyp-obj-y +=3D $(lib-objs) =20 ## diff --git a/arch/arm64/kvm/hyp/nvhe/clock.c b/arch/arm64/kvm/hyp/nvhe/cloc= k.c new file mode 100644 index 000000000000..32fc4313fe43 --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/clock.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2025 Google LLC + * Author: Vincent Donnefort + */ + +#include + +#include +#include + +static struct clock_data { + struct { + u32 mult; + u32 shift; + u64 epoch_ns; + u64 epoch_cyc; + u64 cyc_overflow64; + } data[2]; + u64 cur; +} trace_clock_data; + +static u64 __clock_mult_uint128(u64 cyc, u32 mult, u32 shift) +{ + __uint128_t ns =3D (__uint128_t)cyc * mult; + + ns >>=3D shift; + + return (u64)ns; +} + +/* Does not guarantee no reader on the modified bank. */ +void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) +{ + struct clock_data *clock =3D &trace_clock_data; + u64 bank =3D clock->cur ^ 1; + + clock->data[bank].mult =3D mult; + clock->data[bank].shift =3D shift; + clock->data[bank].epoch_ns =3D epoch_ns; + clock->data[bank].epoch_cyc =3D epoch_cyc; + clock->data[bank].cyc_overflow64 =3D ULONG_MAX / mult; + + smp_store_release(&clock->cur, bank); +} + +/* Use untrusted host data */ +u64 trace_clock(void) +{ + struct clock_data *clock =3D &trace_clock_data; + u64 bank =3D smp_load_acquire(&clock->cur); + u64 cyc, ns; + + cyc =3D __arch_counter_get_cntvct() - clock->data[bank].epoch_cyc; + + if (likely(cyc < clock->data[bank].cyc_overflow64)) { + ns =3D cyc * clock->data[bank].mult; + ns >>=3D clock->data[bank].shift; + } else { + ns =3D __clock_mult_uint128(cyc, clock->data[bank].mult, + clock->data[bank].shift); + } + + return (u64)ns + clock->data[bank].epoch_ns; +} --=20 2.53.0.rc1.225.gd81095ad13-goog