From mboxrd@z Thu Jan 1 00:00:00 1970 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 77D8B3AEF3B for ; Fri, 6 Mar 2026 14:02:50 +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=1772805774; cv=none; b=n9SC4oYUW7O/jO4UpyFlAWv+qBKZATX9SuqXY7qgCqT2A+aYuyQaLmvhiOxDZnnoVEDbPN/HNcEJXfhCqh8a8dYSP2Ua4HHv1fNR67qpQODmr3fzoAUtDmLE85xl1duH1VYXv1dGS5aAUFKHVsKgtwvy58+meAP/D74QJ1BUP+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772805774; c=relaxed/simple; bh=3OQfV3w/2qk9lemOSyqAInJWfA1kcX3/Dpbr8AywQL8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=aKxdKkom/XdchVPy1PzlnhElt3axylVjkuKMz7NTYzfwI/HVSgiIEtmPE/wot5twVCpy6P01wD7jBRMR9ao4uknvwWzOtqA0Hz3H9v5oy4voY3Bdx6R5rWqfQwHNo3+bZSvqQWSyeIbdGsxIAg9wH3dl2ngmcydchc7+UtDSyhE= 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=GA0q+NLj; 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--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="GA0q+NLj" Received: by mail-ed1-f74.google.com with SMTP id 4fb4d7f45d1cf-661aff85c3eso1245828a12.2 for ; Fri, 06 Mar 2026 06:02:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772805769; x=1773410569; 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=CtHGmGW+kuNXfpqkwV8R0QzbahP6BhHBAQuRE9dnG2k=; b=GA0q+NLjnNeaPAAluYbcRBq7jiDl4E0cPz8MM81EeodbtofmR9pLTdrbi4dtkf556C cedfSngBU7wlpByleh112nAdfj7Q6ASSKK9vw0xF5OFWgSHT1+vpa9FTd05j8dO2aHlc DXigjhM1QcfA057AT15YeJ6BE2l6BwRKwh6YJ8O3LtfrKWPPbbifqCdTaDcVZIf9HrEt OywH45JJ4KlckaMk2JHM+6/k5dXuBfJwTU8Gdvz1Pl7Ry8hxSaqrJaheptOv438sGVF7 rpaLC546hS04GgHk8ICBC3wm9S1SOX/7CSdBzYvmZXGJ37seBVniWkbDb8N9ywauJ1BN e8lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772805769; x=1773410569; 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=CtHGmGW+kuNXfpqkwV8R0QzbahP6BhHBAQuRE9dnG2k=; b=ZJw2wck5Bqbf2d0n0ih67OhD9Okreh8lf5j/pR88bNW4czVyUP5idl0vUUerEndhxo z6i5V/K3xih4KEcn/nU1gLBFYrsyqKA8aZ2A4fwskRY0zkHr/OUqHUeVEnybPcHGiPpd VU0ev3iIGiF1J9LY3mej6yE3rDPZoi7RD2wcNaAU+pOgScaXn5DqwKrgCvhIa8e17Y8I CVtiJ27ozSWyETn7mzWfHZg9Xl7MchVgxiTarlV4nCRlAaQn9G6AfRVy5sFbAV0Atk5x cqRaF79USDXpZJcS0fQO5i4WTIMP6mpMJr3CCjgfIB5KUrcmx+6D4Uo8jSXfgMyVylFb DsaQ== X-Gm-Message-State: AOJu0YzfjSmVfwMof5U2XxiwflY/p8I/HeZdBWp69uWwcO+XrCCCI/w7 2JaZ1zHraKtyLl8UFfy2qFb+TN8eKk55RJrEWxPjrShulITT1ufBd3Jcy0oEUYQ7ruN3QGEG5E7 bmudz3gTmNtQIHcTibFIjd4lCdBX7V4EQieFFEj1+/8FUxg9GQRMzMcOLju/2gW+OtUUkONV6dL aEbYnYOrY4rFnb4JJH/qZXciWkHn8= X-Received: from edoy18.prod.google.com ([2002:aa7:c252:0:b0:660:e9bd:31af]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:2807:b0:658:1304:b699 with SMTP id 4fb4d7f45d1cf-6619d50626dmr1271444a12.31.1772805768583; Fri, 06 Mar 2026 06:02:48 -0800 (PST) Date: Fri, 6 Mar 2026 14:02:31 +0000 In-Reply-To: <20260306140232.2193802-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260306140232.2193802-1-tabba@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260306140232.2193802-13-tabba@google.com> Subject: [PATCH v1 12/13] KVM: arm64: Hoist MTE validation check out of MMU lock path From: Fuad Tabba To: kvm@vger.kernel.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, catalin.marinas@arm.com, will@kernel.org, qperret@google.com, vdonnefort@google.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" Simplify the non-cacheable attributes assignment by using a ternary operator. Additionally, hoist the MTE validation check (mte_allowed) out of kvm_s2_fault_map() and into kvm_s2_fault_compute_prot(). This allows us to fail faster and avoid acquiring the KVM MMU lock unnecessarily when the VMM introduces a disallowed VMA for an MTE-enabled guest. Signed-off-by: Fuad Tabba --- arch/arm64/kvm/mmu.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 9265a7fc43f7..cc6b35efcee5 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1870,18 +1870,21 @@ static int kvm_s2_fault_compute_prot(struct kvm_s2_fault *fault) if (fault->exec_fault) fault->prot |= KVM_PGTABLE_PROT_X; - if (fault->s2_force_noncacheable) { - if (fault->vm_flags & VM_ALLOW_ANY_UNCACHED) - fault->prot |= KVM_PGTABLE_PROT_NORMAL_NC; - else - fault->prot |= KVM_PGTABLE_PROT_DEVICE; - } else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC)) { + if (fault->s2_force_noncacheable) + fault->prot |= (fault->vm_flags & VM_ALLOW_ANY_UNCACHED) ? + KVM_PGTABLE_PROT_NORMAL_NC : KVM_PGTABLE_PROT_DEVICE; + else if (cpus_have_final_cap(ARM64_HAS_CACHE_DIC)) fault->prot |= KVM_PGTABLE_PROT_X; - } if (fault->nested) adjust_nested_exec_perms(kvm, fault->nested, &fault->prot); + if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) { + /* Check the VMM hasn't introduced a new disallowed VMA */ + if (!fault->mte_allowed) + return -EFAULT; + } + return 0; } @@ -1918,15 +1921,8 @@ static int kvm_s2_fault_map(struct kvm_s2_fault *fault, void *memcache) } } - if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) { - /* Check the VMM hasn't introduced a new disallowed VMA */ - if (fault->mte_allowed) { - sanitise_mte_tags(kvm, fault->pfn, fault->vma_pagesize); - } else { - ret = -EFAULT; - goto out_unlock; - } - } + if (!fault->fault_is_perm && !fault->s2_force_noncacheable && kvm_has_mte(kvm)) + sanitise_mte_tags(kvm, fault->pfn, fault->vma_pagesize); /* * Under the premise of getting a FSC_PERM fault, we just need to relax -- 2.53.0.473.g4a7958ca14-goog