From nobody Thu Oct 9 14:51:49 2025 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (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 0DA6921146B for ; Wed, 18 Jun 2025 04:24:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750220678; cv=none; b=VSh0RX10OCb7fp9WinhXyHN1PC+/fG0ZJu1W/ED8IOSSxce5uPZk6tWnCjkrU78SC9NUxROuPppsGK6C+zJCnGxLFSfxhNxLAIQYceRmYmx0LTjblSVL3hQKVasSM4YWupq2+n9qKGfqR+1yAg4lqza+wT5AaND5l28B/OmYYQo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750220678; c=relaxed/simple; bh=NPz0+9NZChr+FABsJMTAuN25yJ2sI7tDtR2Lkd4QSco=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=oqWfKQN4xRYjunRyntZZdYZMzC+qflJhvxBdtkLzSxX1ti/e/kOZmVKyxlkw6IDRhcJdm1+uurD+oxcZnTCGIIjfDOJXP/k+PcdU8p4VtwOeL8YcjZpD8mOajTuTy0x9BCa6Hyc17IUhoCY9J4DKgFj/0JKbVPW5dgfh9NfZd2s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jthoughton.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=3HiNoPEr; arc=none smtp.client-ip=209.85.216.73 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--jthoughton.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3HiNoPEr" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-3121cffd7e8so5248175a91.0 for ; Tue, 17 Jun 2025 21:24:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1750220676; x=1750825476; 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=Crtc37yj3I5HY0sOOY/Hc9qKBpXKt+15nfqytsnjM48=; b=3HiNoPErfo7kydQaNjYH+735LMmei2TZUHSQcMwl8H8YOCupVnC5Y3QGo66IOXwSra xO67bvOk7Nz/6AWdeORFdzlVKwYQtLQqFOuAh5fhFA4tZAjblAyhLD0CqDBqruCha7ia sqZDCCf/sqMF443ANY8anWsVnEU3S6FOcS2WU5U2VAbnKAPYpYI2YEGGttbkYO7oMHvw KQswzSS5LhJhrzjGl3cBXlBgNcce/6u1+FDdOH+9bs9KmCiA6rNZQYGQK41+ITk03o4m /C5v+NFcGQwhPApvZ892WmB4qqI7Gg4F6stzBEi5HSz3wF5+tYl5dasALWW/IDGU68UF LG2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1750220676; x=1750825476; 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=Crtc37yj3I5HY0sOOY/Hc9qKBpXKt+15nfqytsnjM48=; b=CKVAjbjt9kWwI4s1UJO7jUhAYHkG0oxf2fZWf7KVUfhQ9fLmlxvFfm8I9cbytV4Tuu W17FzoZo3MCoBYCgd2dvM37zZhUmRwbLYoZjaiaXhxBbyiEHb0lhi8Ux9rGiepsoqqC9 per9cSahfJsjidl9OPfNMZojXb/J/2zXPwEYN1uU/tuXI2suHrHtWUMqXbeWpS0wIX/E 0icvLL6hEBgoblQuiay6FsH8TlyKlvKxw/CfjdEmq8U4KiLR/WM7/et1v7Qo+NrQVcc7 Gpo7Am9270C/VRNq/kuMmU9IHB40+fWKC3b7SNzkJftX5lpOtPs9KNxhcJkHTHKi5Q9o Apsw== X-Forwarded-Encrypted: i=1; AJvYcCUyKxbdRTd4/hRd86ug8HmZ3FG8dz3MsdgzUjAjGRvf3RCchA8KQeyosHniHPIuceX03H0RJVncIoUWrfE=@vger.kernel.org X-Gm-Message-State: AOJu0YypcLZnL9tUetWR9S7PoRKUFIKp4FAyW3UDzvJPlRLworQHixmo kOVXCqHCi7qFuTq2YJP/hPLuHDLgpk+yqGZqhUXq9m0RgAUcEDp517xJcy/Bd1Q6maApfFvVIUB Nk2XJ2oGMtlRLexTOyXRY4A== X-Google-Smtp-Source: AGHT+IECQVYtJtqccD2ckXzkUCRtEGI61f7empdw5CPtw8UB73TqbA6HTmrTRxT/T52yNYKeR/onnUx3D5hsOmVD X-Received: from pjbsl11.prod.google.com ([2002:a17:90b:2e0b:b0:312:1dae:6bf0]) (user=jthoughton job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5245:b0:311:ff02:3fcc with SMTP id 98e67ed59e1d1-313f1c03409mr27710648a91.14.1750220676391; Tue, 17 Jun 2025 21:24:36 -0700 (PDT) Date: Wed, 18 Jun 2025 04:24:15 +0000 In-Reply-To: <20250618042424.330664-1-jthoughton@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250618042424.330664-1-jthoughton@google.com> X-Mailer: git-send-email 2.50.0.rc2.696.g1fc2a0284f-goog Message-ID: <20250618042424.330664-7-jthoughton@google.com> Subject: [PATCH v3 06/15] KVM: arm64: Add support for KVM userfault exits From: James Houghton To: Paolo Bonzini , Sean Christopherson , Oliver Upton Cc: Jonathan Corbet , Marc Zyngier , Yan Zhao , James Houghton , Nikita Kalyazin , Anish Moorthy , Peter Gonda , Peter Xu , David Matlack , wei.w.wang@intel.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To support KVM userfault exits with arm64: 1. Force mappings to be 4K while KVM_MEM_USERFAULT is enabled. 2. Return -EFAULT when kvm_do_userfault() reports that the page is userfault (or that reading the bitmap failed). kvm_arch_commit_memory_region() was written assuming that, for KVM_MR_FLAGS_ONLY changes, KVM_MEM_LOG_DIRTY_PAGES must be being toggled. This is no longer the case, so adjust the logic appropriately. Signed-off-by: James Houghton Signed-off-by: Sean Christopherson --- arch/arm64/kvm/mmu.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 0c209f2e1c7b2..d75a6685d6842 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1548,7 +1548,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys= _addr_t fault_ipa, * logging_active is guaranteed to never be true for VM_PFNMAP * memslots. */ - if (logging_active) { + if (logging_active || is_protected_kvm_enabled() || + kvm_is_userfault_memslot(memslot)) { force_pte =3D true; vma_shift =3D PAGE_SHIFT; } else { @@ -1637,6 +1638,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys= _addr_t fault_ipa, mmu_seq =3D vcpu->kvm->mmu_invalidate_seq; mmap_read_unlock(current->mm); =20 + if (kvm_do_userfault(vcpu, &fault)) + return -EFAULT; + pfn =3D __kvm_faultin_pfn(memslot, fault.gfn, fault.write ? FOLL_WRITE : = 0, &writable, &page); if (pfn =3D=3D KVM_PFN_ERR_HWPOISON) { @@ -2134,15 +2138,19 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, const struct kvm_memory_slot *new, enum kvm_mr_change change) { - bool log_dirty_pages =3D new && new->flags & KVM_MEM_LOG_DIRTY_PAGES; + u32 old_flags =3D old ? old->flags : 0; + u32 new_flags =3D new ? new->flags : 0; + + /* Nothing to do if not toggling dirty logging. */ + if (!((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES)) + return; =20 /* * At this point memslot has been committed and there is an * allocated dirty_bitmap[], dirty pages will be tracked while the * memory slot is write protected. */ - if (log_dirty_pages) { - + if (new_flags & KVM_MEM_LOG_DIRTY_PAGES) { if (change =3D=3D KVM_MR_DELETE) return; =20 --=20 2.50.0.rc2.692.g299adb8693-goog