From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f197.google.com (mail-lj1-f197.google.com [209.85.208.197]) (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 618FC47CA65 for ; Fri, 7 Aug 2026 16:43:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786121041; cv=none; b=NSJSO4Upd35NkXxIi0z7tO2YYaLnSuSH5izvENSNAmxGwQnYRcXPZ0Tt3X1n+b4jm1b+o4bScauUdBVmBhE4HRuG0ECQ/8T8b1Pbi6b4s4ZiUSYyzDeqEa+N8Ahqw831kJ0kY+hf7Vvohpo19wft4B1F1ME20wnG1Wno5ikEWAo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786121041; c=relaxed/simple; bh=WJpZQ0SdOrH7RGvEvyDpMPhGUMqMI5kRtv8KfcRLpcY=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=cxEvXwbI8THv/27SJby64hBNHAURMIuOOFuzuToS6FH3OweIFSdXTkH0OTOimjdQWgsonvg8ynmibPDEJi+75PfhNVFR2urYhiJPrqP4NripLgJtkpMY5d4xzgvzaAFOL3Y0n0gL4T5/nCDs7NLmA9xNXpjRG/aRtBap75VXNBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--sebastianene.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=cSMASzM7; arc=none smtp.client-ip=209.85.208.197 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--sebastianene.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cSMASzM7" Received: by mail-lj1-f197.google.com with SMTP id 38308e7fff4ca-39f44d8edb6so13439381fa.3 for ; Fri, 07 Aug 2026 09:43:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1786121035; x=1786725835; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=7TXLJIzu0sdUTbcYifBsweWW0qiwt6RC0AmUjCHWXcg=; b=cSMASzM7c0+uXiQdQIwGKmSqLxX+y+z1iqYNUhdrn0YfB7dL2nesWHWlGE6LvY6b+q tiM8MOc4o6I15qv2QA/eE3IbY6JhcW18N0mfFJntWW7wrNgiJdAAZ5z70ff5jhKNwvMX QfTajyIwdUhtacA3Gy+jmSwTjVZ3nHVHekE+9hqismQXTPx7DObzhtWPVtQV4/jOVogB da6OE+wfki/Qblm1kydfdlQNrRrX4N8lFWl1QfDJxwNWMQzEZes2I2MLPk8SV2SXqphm hc3HTasJEYgUTbNrvgqVlkM+ctXMRD+9/XVMPrdeqxNA8uHdgF7VvPEKQK3pF7INNMPs TLyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786121035; x=1786725835; h=content-type: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:content-type; bh=7TXLJIzu0sdUTbcYifBsweWW0qiwt6RC0AmUjCHWXcg=; b=PTmUXmwdni7t/sNy9KKJV0Zn0DQxd6M6pTZeiYxcsdpHcdwMTCHvUcbGn8brCAZ25+ tUMCuJdjbRgMl8qaYeX7vKu/bx4sjfPdzjfV0LAuLZgVEkxuFb1hHS1+63I8M+RTp3gn 3RKQLeUtKYqWhLBVUgSHUBuFb+orW/9Wq9XfLsgMOCq8jpsO6wGHC6R1jWRFnNASDMg2 5Ufym+Xjt0q4GWrAM9yF7A19wSdI1BOkPqlk/x4q/AoDuVqhuf083Prmk/O28r+U6Uge CehVM/11nCMlj5yDjGXmXEyGTdNMCL+s2ax7/OhjVo8IziiHrC1svbqlsOTgSuejSuPo ZWdA== X-Gm-Message-State: AOJu0YxsNFp9hzI1C8Dite86GQXL83viGS8cq+W4Bs8pshE/pQ7UbShb tUaRFtOTJnQ2CMdWObpaTT7/qgcQ/+rXdLWElC+uz1+avoWXHUUfqQcG4SHBSBoNeKj6iNGX9qs dWttqXdGuK0ynBTyF/Q+ZCJTb6Mxg1w== X-Received: from ljik18.prod.google.com ([2002:a2e:8892:0:b0:397:f415:3317]) (user=sebastianene job=prod-delivery.src-stubby-dispatcher) by 2002:a2e:bc0d:0:b0:39b:f64:1af3 with SMTP id 38308e7fff4ca-39fe56728b1mr2004231fa.8.1786121034668; Fri, 07 Aug 2026 09:43:54 -0700 (PDT) Date: Fri, 7 Aug 2026 16:43:21 +0000 In-Reply-To: <20260807164322.2970811-2-sebastianene@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260807164322.2970811-2-sebastianene@google.com> X-Mailer: git-send-email 2.55.0.654.g21b8a5bc05-goog Message-ID: <20260807164322.2970811-13-sebastianene@google.com> Subject: [PATCH v2 11/13] KVM: arm64: Prevent the host from specifying a different command queue From: Sebastian Ene To: catalin.marinas@arm.com, fuad.tabba@linux.dev, joey.gouly@arm.com, mark.rutland@arm.com, maz@kernel.org, oupton@kernel.org, rananta@google.com, Sascha.Bischoff@arm.com, suzuki.poulose@arm.com, will@kernel.org Cc: kvmarm@lists.linux.dev, android-kvm@google.com, bgrzesik@google.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, nathan@kernel.org, perlarsen@google.com, sebastianene@google.com, seiden@linux.ibm.com, smostafa@google.com, tglx@kernel.org, vdonnefort@google.com, vladimir.murzin@arm.com, yuzenghui@huawei.com, zenghui.yu@linux.dev Content-Type: text/plain; charset="UTF-8" Don't let a malicious host re-program the command queue register with a different address and size to bypass the commands sanitization. Prevent unpredictable hardware behavior and restrict updates to the GITS_CBASER while the ITS is enabled or not in a quiescent state. Signed-off-by: Sebastian Ene --- arch/arm64/kvm/hyp/nvhe/its_emulate.c | 32 +++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/its_emulate.c b/arch/arm64/kvm/hyp/nvhe/its_emulate.c index b9b71aa18d48..97cfa31d90d1 100644 --- a/arch/arm64/kvm/hyp/nvhe/its_emulate.c +++ b/arch/arm64/kvm/hyp/nvhe/its_emulate.c @@ -429,9 +429,41 @@ static void ctlr_write(struct pkvm_protected_reg *region, u64 offset, u64 value) writel_relaxed(value, its->base + GITS_CTLR); } +static void cbaser_write(struct pkvm_protected_reg *region, u64 offset, u64 value) +{ + struct its_priv_state *its = region->priv; + int num_pages; + u64 ctlr; + + ctlr = readl_relaxed(its->base + GITS_CTLR); + if ((ctlr & GITS_CTLR_ENABLE) || !(ctlr & GITS_CTLR_QUIESCENT)) + return; + + num_pages = its->host_state->cmdq_len / SZ_4K; + + /* Don't let the host program a different command queue */ + value &= ~(GENMASK(7, 0) | GENMASK_ULL(51, 12)); + value |= (num_pages - 1) & GENMASK(7, 0); + value |= __hyp_pa(its->cmd_original) & GENMASK_ULL(51, 12); + its->needs_flush = (value & GITS_CBASER_SHAREABILITY_MASK) != GITS_CBASER_InnerShareable; + + writeq_relaxed(value, its->base + GITS_CBASER); + + /* Restart the CMDQ to read from 0 */ + its->cmd_offset = 0; + writeq_relaxed(0, its->base + GITS_CWRITER); +} + +static void cbaser_read(struct pkvm_protected_reg *region, u64 offset, u64 *read) +{ + struct its_priv_state *its = region->priv; + *read = readq_relaxed(its->base + GITS_CBASER); +} + static struct its_handler its_handlers[] = { ITS_HANDLER(GITS_CWRITER, sizeof(u64), cwriter_write, cwriter_read), ITS_HANDLER(GITS_CTLR, sizeof(u32), ctlr_write, ctlr_read), + ITS_HANDLER(GITS_CBASER, sizeof(u64), cbaser_write, cbaser_read), {}, }; -- 2.55.0.654.g21b8a5bc05-goog