From nobody Mon Feb 9 14:34:02 2026 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 1CFD3337692 for ; Mon, 26 Jan 2026 10:44:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769424288; cv=none; b=ecPnHN6QJMYcyNhSTXUFJZHmADthUFy6rvMX9tNgsltZqyyQvva5Hv8m7dmsGUiYHRuMWTVCwI45OR5SN/vdcjvlWlwIfxePyZtUELVEn0I1mdpMfBdU9GN7CERPMZBbpryoUbIwIJ8D75DLFyAlGtGfSRlotBVmPu2pcKNixM4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769424288; c=relaxed/simple; bh=nnTr5HL8Y/dQvuipzEumtvYWxP+I8ZzG7VGe+d+aJtA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=sTvcx1ZkUsm7wUtTTgwTFYKQHlGYAuQVGGIHyLJt7Y6qhV3pVIV60Gt6XwBP+dxkvz6Kdxv6uu+ew3hbexIp9YDAErO4lC/OFKH/eUvtu2zTZTjH35ItEGUUusdfNJ7vizxUUYO1/O+WMRzdoMSAIXuCfs9Beeg5bd+5qQrW/aw= 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=o4u26+Iv; arc=none smtp.client-ip=209.85.128.74 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="o4u26+Iv" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-47ee868f5adso45987455e9.0 for ; Mon, 26 Jan 2026 02:44:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769424284; x=1770029084; 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=+meh5z0/4QwnO6LSl7j279PrriMLEbu2DSgtDyqQa7E=; b=o4u26+IvJYimne5MRWzBeW1wCPWjgeHLviOCq4bVz0Wc2chZqWOmc0eJHzcTedZ5Jp BrHVvOQ+q4qlxPusKoj+eurUBbLE4h3lWOGl0HeCRTIrWeXwRYt3rUZCF0ZXMC38pO76 P0pP+GBWTKIB/uPI3am8oBNj942OV/rax52jDYObNmcMfLUvxbwQea2kJfJrN+JhPNke 4UkcFZk+06IbU+jvQZHZJBd28LBA5lnd0BC8a5b5Scopz2tKq8HbNU3J7idbyzDwrSE/ xX8ZZW8A7Dl3C7hGs4dV8v4HU/g8069Xhw2ux1QVOmIP80EgLyLNS4ruo3gPBuY9dLiM zz/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769424284; x=1770029084; 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=+meh5z0/4QwnO6LSl7j279PrriMLEbu2DSgtDyqQa7E=; b=B6WdhUP/LOQottrepjpwDht16iogblddDu6H3kNQ8XLx7NhGcsVSHoO2eUzAEgzrYX Xv9cXkqh9bdlDcpzWtTOsehV5iDSfOSuYWO6VVOr6cq1ZxsZD9+QC78qsZkJ12qZsp7u 7reg2jYA+FDfzSSQbusbABxQZVRQxzpeaeYrfX/YfxI872uDmCjCqOrdO9IWlZ7NORlc cTnEwKr9U+IRTAB26bVwRHBIId58qeYJbYidelkPsbnpokPAFxh7QcysG+X6yD7KzJBy 8/PEtJaiTXSx5l+lFpfTNRfBhe4L40tgw0LDMJ3V3NnOXqWf8kpodN/fuEr0xHKBuF9/ 0yzw== X-Forwarded-Encrypted: i=1; AJvYcCVMLfYepUQ1kIBIPy53bLuGvUXku2j/b7wzPVay+r1Ch9BOQlsKOeoR+4fwzORC6uJAETHIRkg1q0gscf4=@vger.kernel.org X-Gm-Message-State: AOJu0YyEPyO2PgeL8ANwkh2vmpNdNrJDilXOfwwqioKdSqYIYcc/pbZL Qd3XpdVe9LZIBLoCaj9y6VlfAW2+FcAiKZURUaiXyrbM3W9SnIPyqgFWnr6zNFBHtRqnowELY5L FlD+Q7zckcbhv+8WNVAX0yQ== X-Received: from wrbei6.prod.google.com ([2002:a05:6000:4186:b0:435:c02a:cdd4]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a5d:5f44:0:b0:432:85eb:a3cc with SMTP id ffacd0b85a97d-435ca145617mr7262377f8f.19.1769424284248; Mon, 26 Jan 2026 02:44:44 -0800 (PST) Date: Mon, 26 Jan 2026 10:44:09 +0000 In-Reply-To: <20260126104419.1649811-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260126104419.1649811-1-vdonnefort@google.com> X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog Message-ID: <20260126104419.1649811-21-vdonnefort@google.com> Subject: [PATCH v10 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 dependant 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 2.52.0.457.g6b5491de43-goog