From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f73.google.com (mail-ed1-f73.google.com [209.85.208.73]) (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 4A62B341074 for ; Mon, 15 Dec 2025 16:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765817521; cv=none; b=d5iKaBcPDTwCtGCEBnIbvcEet4tUKA3Eq7qGQAoO9L1ZEl1uXiYY4dvBu4shhBuUf0wJNMqtOJFb/WrKlMmXZqaC6KMzJh/L3zTraHqpaYpt1Va2gc7SMYqkqo1Tkq8rySivS3bwt0FkZGJRTiqP5Nnb+QFKZGn0l7LopA0NClM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765817521; c=relaxed/simple; bh=H+BYPeuC46/cZwkzUGpKRp4PEKTMr0g8kH+Bp2Om/eI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=sdva1Ow/7zY0YdYDxVL47LPNhL8oDHvCYgeDGamWLQEjV8p+1mieK3w3NzdfdFNcgt0zp3LTbXapSQjHKsdn8ZMvKEA1VHTnDty7f5ug8jCtr9gcdct/3KwyVVG5TrW4UHmcJGVmuubzdqgWPkDjaybuq+t6NdlFvCGGmfg/tRY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=vpsWTE5q; arc=none smtp.client-ip=209.85.208.73 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--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vpsWTE5q" Received: by mail-ed1-f73.google.com with SMTP id 4fb4d7f45d1cf-64969d8d4f2so5351543a12.1 for ; Mon, 15 Dec 2025 08:51:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1765817517; x=1766422317; 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=rkHSL25koHVDTaMmCRcby8S1CrLCFqcfDXkn0dsUTFg=; b=vpsWTE5qIGXjoKwxTKEuoBKCjSuzjeoBw1e43f7xkutPvnFhrltDJCTM+7L6VToad/ SJIppHe4VTZALh8jZjIu5UBQ5N6ki0LCrvIKIe58M1Vy39fKv7qr0XHGBKiOAAWyYCr7 V1XKIagV/S4WQFPhQ4LIn6K+ZchhzVQi/9+DpX0JzwP5eqIHD3989q4l4owASCWTmoXj CTIYAmPdYb2iC3ISlKKchYXrjRijZgG8q6i+nbmoyv2DOaX2u72mFBQ9CMcYChX6it5w m7uYiabUchpmuKp7DNXqZ8Oip9Pakqe09Wh848VW0GmHV3Grgo2vwWKphkiGUpEksf3H YETw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1765817517; x=1766422317; 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=rkHSL25koHVDTaMmCRcby8S1CrLCFqcfDXkn0dsUTFg=; b=kvrPWzuBqIRUb5Y510L8EruqA57kbq8d8IrOukjFz40zkws8oPB6YvoOizIrfCSDJu gGgn9KCp3iZd9PHTWR40V+Xb7cRHAiK1c433DRziFIzKaj/cWNWCdSU3y1jVeH5pK7Yl GnZsI/M5JbB+5jasE+Z45qNnSxhlk1YspCniLxJ/vCbCqErwyqKG8ZHJPV7LteXcWvO9 eYs37C7ktZljFdGUp4hkUqu98WLGvmLAFa2PqLmrLI4hBf45azw+FiirbYluAxN+U2yJ 4V403Z33IIcGh7EUNEKmavsYcc5NNfZaCnq0Iu1kifDRNSZ6z2sntzroZa/4IFesU4W6 H8cQ== X-Gm-Message-State: AOJu0YwGIiaHMag56OK9jatAtSuvhMVGQ+lzrO8w21WIfT65Dn3Sor3i 1Ofz9m7gD0XQ+hLV53JZeAYWh+bV3IUr4nRDZoD9ZlbavU+FWP9WiPPHF4rZJMm93iWm5VBAs2F 72KWuqKvE2ga6JplXzSMpwoF42qr+5TUJeERduyGiGs1Nr8NUOxnDDYXaksJrkKbHNtp3TNN0M5 Pt6sMayrRuOPFEkM83kqJOxY5vmME= X-Google-Smtp-Source: AGHT+IFrHxiEYHDjT58c4YVmrMD5eO1DrDlCmV6f5ukjJAbXvW2Vssi5+5Lw36DE9YHOiX+0KsCF3RMJMA== X-Received: from edbdk5.prod.google.com ([2002:a05:6402:1d85:b0:649:1567:4ee3]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:d08:b0:641:8a92:9334 with SMTP id 4fb4d7f45d1cf-6499b1301b7mr10482727a12.6.1765817517246; Mon, 15 Dec 2025 08:51:57 -0800 (PST) Date: Mon, 15 Dec 2025 16:51:51 +0000 In-Reply-To: <20251215165155.3451819-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251215165155.3451819-1-tabba@google.com> X-Mailer: git-send-email 2.52.0.239.gd5f0c6e74e-goog Message-ID: <20251215165155.3451819-2-tabba@google.com> Subject: [PATCH v2 1/5] KVM: arm64: selftests: Disable unused TTBR1_EL1 translations From: Fuad Tabba To: kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, will@kernel.org, pbonzini@redhat.com, shuah@kernel.org, anup@brainfault.org, tabba@google.com Content-Type: text/plain; charset="UTF-8" KVM selftests map all guest code and data into the lower virtual address range (0x0000...) managed by TTBR0_EL1. The upper range (0xFFFF...) managed by TTBR1_EL1 is unused and uninitialized. If a guest accesses the upper range, the MMU attempts a translation table walk using uninitialized registers, leading to unpredictable behavior. Set `TCR_EL1.EPD1` to disable translation table walks for TTBR1_EL1, ensuring that any access to the upper range generates an immediate Translation Fault. Additionally, set `TCR_EL1.TBI1` (Top Byte Ignore) to ensure that tagged pointers in the upper range also deterministically trigger a Translation Fault via EPD1. Define `TCR_EPD1_MASK`, `TCR_EPD1_SHIFT`, and `TCR_TBI1` in `processor.h` to support this configuration. These are based on their definitions in `arch/arm64/include/asm/pgtable-hwdef.h`. Suggested-by: Will Deacon Signed-off-by: Fuad Tabba --- tools/testing/selftests/kvm/include/arm64/processor.h | 4 ++++ tools/testing/selftests/kvm/lib/arm64/processor.c | 2 ++ 2 files changed, 6 insertions(+) diff --git a/tools/testing/selftests/kvm/include/arm64/processor.h b/tools/testing/selftests/kvm/include/arm64/processor.h index ff928716574d..ac97a1c436fc 100644 --- a/tools/testing/selftests/kvm/include/arm64/processor.h +++ b/tools/testing/selftests/kvm/include/arm64/processor.h @@ -90,6 +90,9 @@ #define TCR_TG0_64K (UL(1) << TCR_TG0_SHIFT) #define TCR_TG0_16K (UL(2) << TCR_TG0_SHIFT) +#define TCR_EPD1_SHIFT 23 +#define TCR_EPD1_MASK (UL(1) << TCR_EPD1_SHIFT) + #define TCR_IPS_SHIFT 32 #define TCR_IPS_MASK (UL(7) << TCR_IPS_SHIFT) #define TCR_IPS_52_BITS (UL(6) << TCR_IPS_SHIFT) @@ -97,6 +100,7 @@ #define TCR_IPS_40_BITS (UL(2) << TCR_IPS_SHIFT) #define TCR_IPS_36_BITS (UL(1) << TCR_IPS_SHIFT) +#define TCR_TBI1 (UL(1) << 38) #define TCR_HA (UL(1) << 39) #define TCR_DS (UL(1) << 59) diff --git a/tools/testing/selftests/kvm/lib/arm64/processor.c b/tools/testing/selftests/kvm/lib/arm64/processor.c index d46e4b13b92c..5b379da8cb90 100644 --- a/tools/testing/selftests/kvm/lib/arm64/processor.c +++ b/tools/testing/selftests/kvm/lib/arm64/processor.c @@ -384,6 +384,8 @@ void aarch64_vcpu_setup(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init) tcr_el1 |= TCR_IRGN0_WBWA | TCR_ORGN0_WBWA | TCR_SH0_INNER; tcr_el1 |= TCR_T0SZ(vm->va_bits); + tcr_el1 |= TCR_TBI1; + tcr_el1 |= TCR_EPD1_MASK; if (use_lpa2_pte_format(vm)) tcr_el1 |= TCR_DS; -- 2.52.0.239.gd5f0c6e74e-goog