From nobody Fri Apr 3 14:18:29 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 8171B343216 for ; Thu, 19 Feb 2026 15:03:48 +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=1771513429; cv=none; b=s+/Ir7QpWT+P9APWNrauNFpQhNZiQpjyj7kl1EW/TM3hCvpbhZvjsQnPh+GQuJdCNCLAyVgFlkj5hexwxLXv7uR6PG3gKT/ojeMI65bCFs6WiU8xq+MxdwF2F3WRoLF5AKGuTUZEZkXDxk+zinMYwbmdUuXkiALf8K/Jk22usmI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513429; c=relaxed/simple; bh=RKbQOpKLzyAI1YMOMrFprtXk9TGxMOVYooJ2mkz5y7A=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=YEY1tKh+g45oSLsSdZSat3r/nGuLP0lzc7RL/90WPP2/xP4EbVhracTz8mM53oCHXhzPd37w0JQUJZObcWri5HKe16oPQOcFJH9aqUyF04bW4+BC5se4Ckp+ebSfW45EMXVN9LJ2sTJ20QzquCqPyH43zJjgm0BZTDp7uwAasl4= 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=SiymNKxL; 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="SiymNKxL" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4836abfc742so7361105e9.0 for ; Thu, 19 Feb 2026 07:03:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1771513427; x=1772118227; 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=4+WeYCHm29WX1Oz+Ipz9cvL1JwZd5S77G6D55KrRRUU=; b=SiymNKxLo3sFOR6Umz0F8Cx+fPdnxBZs3qPwrYVJIyKxyUy8ukDlvNisiSDSBBiCml 3JfTw92lj9Z1f+fbfNXswp47lRibXb3jFtC8O4u2/SdE/iymsHc146/CMqJamoZ7dob1 BdAh9ffq7FPrhuW/4j68XgulLy9vp6BDiNaadslcsTo+ULxko+IZcVv/PC2BDfim6vMw aXThUqz8H8iZsKu4+hSJAdwYuT2np9VY1AdjHuPtS5pD1CHR860UdKYWBnIsH0vVdzLR OsNpZ05mLongWByTSi8PYjB4k276yRynFlq6pOS3Vo4aeYi9eOOHfilAuCSu6bLkXEhF MYUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771513427; x=1772118227; 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=4+WeYCHm29WX1Oz+Ipz9cvL1JwZd5S77G6D55KrRRUU=; b=Q37OINeG3BpXWH3id8N4fb4lO43kLOXPOUgm/nsP1VjWWznMknqfHXGoDDPOPymUjZ fTrcqXpk8p9e2x2bPeppOI1xHMqFQfLaxT/L8UNGQH8KeNep+WxOM+Qv0qs5xJVIQMWL YLA3bm7uVbRMCNk9cQ3HZZ7EC+iH6KTksyvP2XMwoEsPk5mtwmhvyQ2I9VN5fTnCr4wc CVHrxuvp87ftAZSnkRF9yNVoQUgEBfmMRheFRcUuwO4qw6UtlK0aCahskjgegdPfxwtA cEVvnwsvuWDQuE0bIV+E1EmixcYhKFZU+YQqYzXmjvXHOJLzsxz00A/tIW5WRDvWODvS CNSA== X-Forwarded-Encrypted: i=1; AJvYcCVPy2/1vk/yxkWA1i9iZn1zr6i0U/oB3KZYjC5PNi54TLmXU6vR1yci0bAiyElJSrbntukcCgZXgwYYVWE=@vger.kernel.org X-Gm-Message-State: AOJu0YyxkmG94MW9qlkbxFzEeH1S0WHIl93KjUZMe4GX+D2LBSHoFdNm FCwp3QWLmNN0tPRohlHTshgwBIko28FKd1fICEyybMdOvKKxEsyk//ZGcvn6R6/OgfdOkMUYVgQ lb/5nuyzwMV1jmR7QhZkstA== X-Received: from wmep7.prod.google.com ([2002:a05:600c:4307:b0:47f:941a:613d]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:3e8f:b0:45c:4470:271c with SMTP id 5b1f17b1804b1-4838f15c50dmr167483695e9.18.1771513426701; Thu, 19 Feb 2026 07:03:46 -0800 (PST) Date: Thu, 19 Feb 2026 15:02:57 +0000 In-Reply-To: <20260219150307.14538-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260219150307.14538-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.335.g19a08e0c02-goog Message-ID: <20260219150307.14538-21-vdonnefort@google.com> Subject: [PATCH v12 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 2.53.0.335.g19a08e0c02-goog