From nobody Sat Apr 11 13:54:41 2026 Received: from mail-ed1-f74.google.com (mail-ed1-f74.google.com [209.85.208.74]) (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 566853BED4B for ; Fri, 6 Mar 2026 14:36:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772807777; cv=none; b=Ntp6kici7dMKpF4mSSXwSsfTNXWhpGDET4h/Bx6ahDokSxznsuhAEkvL9bDeSNIgl/xhER1f4UoVBXQF9O2+Et/HOTrXXGmeUdL3mqROOpT7doI+0RfaNTZRH0G5yw7MZQ+v15X51dZE3BZS505aSGLUVG4oD0nzlzgSi/oTTXg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772807777; c=relaxed/simple; bh=h2rVCYiv2RErJ8J/DPs4R6liat0vq1OWoPSAfx6DS2s=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=eYKscLGSsq2pa6qtdPRzutmX6ACE9pOzb+w4CmIcyYSNZZD9+c+ucVddyitfvCq/+Xh4ov4z5cmxdDyZ5upZby7PvRPDqj3h531uQpsx+TT8UBMqHtzGmNlELLKEI1psNZnHsfnP3j8qYDVYowhtBz/KQq4Zc7SFFlNvq8VJMlg= 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=3TpykPHX; arc=none smtp.client-ip=209.85.208.74 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="3TpykPHX" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-661aff85c3eso1313694a12.2 for ; Fri, 06 Mar 2026 06:36:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772807774; x=1773412574; 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=xnACahr8ULD6CcAQo9gjmAw66hUMbPmLgQ2wO/RqDz0=; b=3TpykPHXQU3ww5fDK/M2qWCg34NpDgpsq3NnEADVs76ZiNFBtq9w+2KV0QJn1Df2nw T03htRbS8hOH2iAxLhlHHhZZTdgEVVFVVzmtil9bZq9FTljpJjjTn7XcdPR8gYCDE5K7 YO/Q86yVAGwDWM4tGxWfS+1D8nqLEH4R3jx9JEtlauKoOlpAQGW2/pERMTZhBVs7RWF7 NdWLcP9wB8PqdwWWGtWg0D8HAkETmSdYEzJxE7+TrdKWI3lRdhNgA8zfRWFf8+PI8HEv 1qgsTnXcSednLdq/VIMGyz7gKUDYYwL8d0qmKUsKlqXkvDXnDlZBqIWyCRZCt10N8+Oy YmtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772807774; x=1773412574; 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=xnACahr8ULD6CcAQo9gjmAw66hUMbPmLgQ2wO/RqDz0=; b=hT/NWOK8hfbh4YAjEAlRj2U6StKwEfjmv1Cw2DdhqpClyQc3uHP5xO0wj8Q86b96V1 7aaLBcpAOYvCUp6CLewk+ix9wfEJseecIQ2FuGunmELi71T0r9abYDGUoM13I4rht/Qb aNgk5b8s5FelywaLxj6ps9icedhQhpyPIvlD/qiMHDYWGZLRteGptqlWM53lS861bM3F p2Xv7gIBTFntfZzfQHHhoEPEfhAACs50QyaIIqIHyU1fO/K0kwiOqrW8na7XKN7Q9eQC MTUsQseye3jo2W31yyD3zUTbqtQ1EfHp/V0SRJMnXxUoXqf1+j5C3QksvPz/8yxXw/qR lERQ== X-Forwarded-Encrypted: i=1; AJvYcCW36LxxXZYmlaCqcnnekazG1HsqH03h+G97Hmn8Cjc+tqiYhtIbCiwfKjmA78hz8RDuv1KFd6FWXOOn0bs=@vger.kernel.org X-Gm-Message-State: AOJu0YzpSAGFyH5p9EwR/leFuLoO1finn1laYVAwTe5Dhub66cuTllSj wxtnCBF4UGxcDu4GAiaQhOhiM6kpVWnRoh6xLDb4xWFVrIJLr3D30/VtROEqVhDliXkpXNvvziv azCF88SRjw0lsBUeYhyk9Kg== X-Received: from edrs15.prod.google.com ([2002:aa7:c54f:0:b0:660:a4e3:2ed2]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:430c:b0:65a:2ec5:99c0 with SMTP id 4fb4d7f45d1cf-6619d4565b4mr1408474a12.3.1772807772463; Fri, 06 Mar 2026 06:36:12 -0800 (PST) Date: Fri, 6 Mar 2026 14:35:24 +0000 In-Reply-To: <20260306143536.339777-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260306143536.339777-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260306143536.339777-21-vdonnefort@google.com> Subject: [PATCH v13 20/32] 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 2.53.0.473.g4a7958ca14-goog