From nobody Thu Apr 2 17:23:44 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 9CCCA3EF0B5 for ; Mon, 9 Mar 2026 16:26:22 +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=1773073584; cv=none; b=TPpRsioQW9ZgztUO9zNa9/i06thFw8nKf7z0KuPfCvww0JBrDDoSdc75clrVjohHJgR52hF2WoNPWp86puj0mbGNskRn8p5sFAbZZHmGr63ha4uKemXa6fOClvg5f9KTv8FP56h9v8+g5dqyyRFJ/QDsRWJIfu35r8IqgEsghwE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773073584; c=relaxed/simple; bh=h2rVCYiv2RErJ8J/DPs4R6liat0vq1OWoPSAfx6DS2s=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=DD1KmwmCNK2lciOwq43K7Fpir1TQrExpfVGvvGILUTZnT+5Cu42yUmEWgEaPrD7VWHTTLylhU6JGgHxH537AXKzt7yRR1zY6PHcG/+u7T7aXKwWCHRR65KSsqRmIBIvuJEF/luhafZYBaPE/euQLRr8tyt+YJ2hebqghIZ54kww= 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=qptiIU2D; 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="qptiIU2D" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-66142e571c9so4596752a12.3 for ; Mon, 09 Mar 2026 09:26:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773073581; x=1773678381; 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=qptiIU2Dp+LYVMwH85ToBRqDuarCGGS3PE6QnA3+Es0G5edRT2/5Ib7WeOfdJhngG6 hjX1Cj+jvbE+2SX8JK1Hg1BEzhv6ZiSN40mDa2OCMqL5V2V+vbp81CyByxLq3FMpz6sE XmlPSXOS3Ui1iKhX46OyFa6ugk4YgLbx1lazVNB35A4Dvu2iNIiXKUE3IzGegwZgEkCK m6mPUPwuefQECm79TNBFzgTtdhTaOF7IYSr60ON9Ok+wKDcKAV6wVG4dgk9HQUugrVgn HJe/bn7wL4PBuGnnuWE36+sgNmTbeQ35pWDkWWsIuzRZbYH82x7qe/OtxpLDihlo206T w1lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773073581; x=1773678381; 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=oZjZvCnt1HEV/CY93j90bQtl3mOY0deJpgFVrnirRop86fPGV4qs+iHSUIOxx5ALpR q/TieaPA83TP+iKnCCbAiAGDqHlDuS+J9my/AclJd5OOX7do5sgPsJTZj7l87D5BmpIL kJ7q8WEpbPDXUVPaBeyZaDAliABrDNOblFgRTb5mXAn/yYYXCa6cJJUcHCy6fOqRpAgl TGZsapuA3L/o0NasmTFcwLeSDZBglDdOzAtqKe9VCMcMW1fJH6a42cUOjc/5Pcm2bSBP +xjzf5w7QaGTvofBqFeyPnqfBna4mhqjalYgw2U/cBRXNDtRkOpco4lhysfklWqKr4+I 5tNw== X-Forwarded-Encrypted: i=1; AJvYcCWuW3VTJTT4VezDhWOw1Bd6BSbhE1hr3hTDc1x5vcNMK3X13gY5wqI1APR7ZKVgLq9yyLXWwSbndMyTmNI=@vger.kernel.org X-Gm-Message-State: AOJu0YyfXgxgubN5OQahNEF/Ih4LLZZ4r2eMheuU3i1bUfyt1Qwx25iT Ct+d4O6h89zTyR1Yk5JmQ8z4sa2jrtfFckb2Qwn7QyReM0T4JpTfcYbVyvHOWuZEzVFazmLKW8i ZWvOgI9eW7PDkUVGaNPUhwA== X-Received: from edbdm18.prod.google.com ([2002:a05:6402:22d2:b0:662:8221:aa6c]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:3643:b0:662:b884:d1c with SMTP id 4fb4d7f45d1cf-662b8840e10mr161656a12.10.1773073580808; Mon, 09 Mar 2026 09:26:20 -0700 (PDT) Date: Mon, 9 Mar 2026 16:25:06 +0000 In-Reply-To: <20260309162516.2623589-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260309162516.2623589-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260309162516.2623589-21-vdonnefort@google.com> Subject: [PATCH v14 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 2.53.0.473.g4a7958ca14-goog