From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f202.google.com (mail-oi1-f202.google.com [209.85.167.202]) (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 8EF923B637A for ; Thu, 9 Jul 2026 22:37:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783636641; cv=none; b=Va8CaG06QdHEmywoWq5qOnHWChetIMoI2rkmtrSpEix704iPU6vtJ99dFJR6e2sqmfOyIARwZACHD2JvAgx7W0934V/0H63f6NRknPSIrrfOpAc6lgP50mg+wjpBW5AYYOj4OJ0mbGUwAFJFmwOuhz1fst0xwbZJWFF3ogFtzbc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783636641; c=relaxed/simple; bh=OWCxBSzaeWIE2U5n1eWlPbSfhQNJbN6VFfYTdf5ETt0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=GIWTT64wsbHGfePKVXTpjFuoDvTiJhg2QCG1dJF1b5Gv86Tuf8OjPmzuLalhdB7KOHIFv593eqBpTD00pFCEsDHp8wXEhfD97qHbASP+zsJbMePIQkZNNGa5oqcGihFJAhkhSlndBTpH7Wosw/KLKpZlIeCDknHUaCsgbRpCObs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--coltonlewis.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Al70bSo/; arc=none smtp.client-ip=209.85.167.202 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--coltonlewis.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Al70bSo/" Received: by mail-oi1-f202.google.com with SMTP id 5614622812f47-487059fb570so484553b6e.0 for ; Thu, 09 Jul 2026 15:37:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1783636637; x=1784241437; 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=78osRNk8qRzph/366BzOmfMhZhXhz27WDl9JWZTx3ao=; b=Al70bSo/1cjYQpXbFXns7AWSlORSpH0raKYt4Hx/CccmhoFA4IYskk+0fMu2Nrcz6z 6JtbRivVHK6reg1vTJJJbPaVS4JMlrQiNsNOSB9t0R1YBBnSmsdl4LqTTuzoSHlDYFmz yoaKuJt2fCzuAcC5xoGY++uOjlgJY3xk/LDOTAGw2+wYhGsrWoaNjtY8tKc6Sp231LZx gMC1wLbYVgXsHybKQq0AxzauXFunJBwyqBnxdQDun6kuriXhSQMw9RRJdNjDI+ZbovRy m1AHzrfWqdO8mYFd+JK38ZWzVxzrsZpukLYRYe30tIAhQ8l3Sgfn8Kn5Almq15hVvcGN Ccrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783636637; x=1784241437; 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=78osRNk8qRzph/366BzOmfMhZhXhz27WDl9JWZTx3ao=; b=liTazAMMZLKYDymLPGeVYS29UMnvS0qwIxCVjcTb6FWa6kc5Relz31HiJ7XI6Lbe1c /ahPq1F2EDKEItH8slxPYaxyM4wWrYD+HBahVt/B5EK9RVunHv5tGLHrBMS+s8nFNAEz BP+HDkAjnsgSzBFiFK1u0hOV0y8D5Okh/PIDjsB+FDYseT0159Lo4XLmuR3onEEze4Wp K+ZRmjQos3mQU4+Qo/uFpcbQBMkoU2r+EGgoqvnS5EUvYnSny7eFZtSpR78oceiDFr1h /9mGCXn2IJolr5JDlj0228jI3SDxQ9+iX/BO+AOVESeP02myhqchnS7Xfc8tfEYdp3Rw ruCg== X-Forwarded-Encrypted: i=1; AFNElJ9ERu6/Y+5/WyPocaez23t3LnFS+P5YWJVt01bdsO39PYOBq/C3PQKOtw4oCEXdW9nFH8EsFXY=@lists.linux.dev X-Gm-Message-State: AOJu0Yy9eq1SqAQEIt1dsZXgRi6tkXmjMYqqJG/OYCRM8hgzx/qfl9DQ v//XJH8/qYo8x4ySrz23yvAUDNFuW8eEZkEuwtGgz2B5AbrA08yWQVocdEY4tQHkmcAt3vQl8TQ iG06PscMkeKequvKl665ieF580w== X-Received: from ilbcl1.prod.google.com ([2002:a05:6e02:3781:b0:503:6571:319a]) (user=coltonlewis job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6808:250c:b0:495:f74a:5bed with SMTP id 5614622812f47-4a203fc3ef9mr7510176b6e.28.1783636636840; Thu, 09 Jul 2026 15:37:16 -0700 (PDT) Date: Thu, 9 Jul 2026 22:36:00 +0000 In-Reply-To: <20260709223604.12934-1-coltonlewis@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260709223604.12934-1-coltonlewis@google.com> X-Mailer: git-send-email 2.55.0.795.g602f6c329a-goog Message-ID: <20260709223604.12934-4-coltonlewis@google.com> Subject: [PATCH 6.6 v3 3/6] arm64: Fix early handling of FEAT_E2H0 not being implemented From: Colton Lewis To: stable@vger.kernel.org Cc: oliver.upton@linux.dev, sashal@kernel.org, gregkh@linuxfoundation.org, mizhang@google.com, catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, ahmed.genidi@arm.com, leo.yan@arm.com, miguel.luis@oracle.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Colton Lewis Content-Type: text/plain; charset="UTF-8" From: Marc Zyngier [ Upstream commit b3320142f3db9b3f2a23460abd3e22292e1530a5 ] Commit 3944382fa6f2 introduced checks for the FEAT_E2H0 not being implemented. However, the check is absolutely wrong and makes a point it testing a bit that is guaranteed to be zero. On top of that, the detection happens way too late, after the init_el2_state has done its job. This went undetected because the HW this was tested on has E2H being RAO/WI, and not RES1. However, the bug shows up when run as a nested guest, where HCR_EL2.E2H is not necessarily set to 1. As a result, booting the kernel in hVHE mode fails with timer accesses being cought in a trap loop (which was fun to debug). Fix the check for ID_AA64MMFR4_EL1.E2H0, and set the HCR_EL2.E2H bit early so that it can be checked by the rest of the init sequence. With this, hVHE works again in a NV environment that doesn't have FEAT_E2H0. Fixes: 3944382fa6f2 ("arm64: Treat HCR_EL2.E2H as RES1 when ID_AA64MMFR4_EL1.E2H0 is negative") Signed-off-by: Marc Zyngier Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20240321115414.3169115-1-maz@kernel.org Signed-off-by: Oliver Upton Signed-off-by: Colton Lewis --- arch/arm64/kernel/head.S | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index e32c8dd0b17a7..e0e710b36da37 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -576,6 +576,21 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) isb 0: mov_q x0, HCR_HOST_NVHE_FLAGS + + /* + * Compliant CPUs advertise their VHE-onlyness with + * ID_AA64MMFR4_EL1.E2H0 < 0. HCR_EL2.E2H can be + * RES1 in that case. Publish the E2H bit early so that + * it can be picked up by the init_el2_state macro. + * + * Fruity CPUs seem to have HCR_EL2.E2H set to RAO/WI, but + * don't advertise it (they predate this relaxation). + */ + mrs_s x1, SYS_ID_AA64MMFR4_EL1 + tbz x1, #(ID_AA64MMFR4_EL1_E2H0_SHIFT + ID_AA64MMFR4_EL1_E2H0_WIDTH - 1), 1f + + orr x0, x0, #HCR_E2H +1: msr hcr_el2, x0 isb @@ -588,22 +603,10 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) mov_q x1, INIT_SCTLR_EL1_MMU_OFF - /* - * Compliant CPUs advertise their VHE-onlyness with - * ID_AA64MMFR4_EL1.E2H0 < 0. HCR_EL2.E2H can be - * RES1 in that case. - * - * Fruity CPUs seem to have HCR_EL2.E2H set to RES1, but - * don't advertise it (they predate this relaxation). - */ - mrs_s x0, SYS_ID_AA64MMFR4_EL1 - ubfx x0, x0, #ID_AA64MMFR4_EL1_E2H0_SHIFT, #ID_AA64MMFR4_EL1_E2H0_WIDTH - tbnz x0, #(ID_AA64MMFR4_EL1_E2H0_SHIFT + ID_AA64MMFR4_EL1_E2H0_WIDTH - 1), 1f - mrs x0, hcr_el2 and x0, x0, #HCR_E2H cbz x0, 2f -1: + /* Set a sane SCTLR_EL1, the VHE way */ pre_disable_mmu_workaround msr_s SYS_SCTLR_EL12, x1 -- 2.55.0.795.g602f6c329a-goog