From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 AF36E43F4C2 for ; Sat, 17 Oct 2026 11:03:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792235000; cv=none; b=Wnx6OcV7AJ2pbT1uNRH8Ca3Rz7fQV1pucPq8vfLM38cntmLZXhr7WY7fs/Mo6YyZz1NvyUhpqnwvZJXmkeoRBTUvyVyfKQCyOyZwQcJm29ZULBpv8r4NhF4WgI1vWbP3DDXZ4OU4mUOLS5jG5JDx6qFBfdzP/hsR4TJGH5GtXNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792235000; c=relaxed/simple; bh=luspfJ1xZI4NzBO23wK7yIzNkEv+cTp75VYBXkmFvWU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Oob7noasCwabaJWZMP5MAwh+qX1YW3qPWCf/bYlF2Z0IVq+j+d8LF4gD8VhrJVam6VLiBiHYdaLQRiiCuZBQAhITqOATHZOvPmT/fi0CaaNPpJWqNKtarKnc0WpqC7cr9VR8Sxlou06jY74jDOd3m5VuQkVFp3Gz059EOg4CSuM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=HFGRgl8x; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HFGRgl8x" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-2e95bd1c14cso5454205ad.2 for ; Sat, 17 Oct 2026 04:03:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792234999; x=1792839799; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Ny7KTMx+qld96qza0vCY0Dx/Bp+/LmW5iI7Izuhy18k=; b=HFGRgl8x2pvUeS+IOBQT6G87n9ULbCa/xyH7KUFuDGhfLgAYYUgighZzDY+sPrdEgk 0/YHQWnuBexsNgLfQpgdAy2bXHYxJsZUzrHtI60HGefIGx2383Bq0LGjHit+ZwiC7uK2 +IJbdFWyeFgP555ht1n5Ms9Bg6598Bmm6IMcST8xE367OU9zxmT/ySS/U4Bc4Kz+Hl2e KKoeSV/WpO61zXBQhYHrf+2xsQJzo6LbwUIiIBHL1/zPaasiMU4iZnIdpZ/IXSBWCZNE nf3Os+FbQSfcNfsE5T9prXGJq0D01/6o3ZNCkB+21BPhxYiagaenZBfAwA51cYpbmax7 C31A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792234999; x=1792839799; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=Ny7KTMx+qld96qza0vCY0Dx/Bp+/LmW5iI7Izuhy18k=; b=ufPMGr9Xan2nsGN9AJKYDDD3ZB5UB5PWrdXt0blp0Y6mvwwLqWrzFa+mDtzXXOMGJf Lt1TI8JwnNQuQy4l+VXccd4Hs3w3jGQ1GQoVYBEwd594isV8hawHvptZFVRy/IyY/Sf9 dJ/sMA40HUTPj8pMUkFcBpilW1tHkbiQSIcjk//ZmQ5pVB1aFLjShcichyst3Jve9li0 MPTnUCS2wEroshUeMiipgUis14O9LFDA8NorBhAUfq8oc0lTXUdZNB2ls2AFtS/3pu+G lkUf5JsMGH8MyVIGqPGegNSm4lrz/l74BJvwmybmRqRtswWk1BFufbI/BL57Hq4bhdHU zaDw== X-Forwarded-Encrypted: i=1; AKwUvByFVrMJwOfvbVvrEFUHLQmxdHWFyiOHCJkMAZyCXiCpvD8XSZoWD5xkCqaXceQ1ubRahnAiFzZP1yWtsvM=@vger.kernel.org X-Gm-Message-State: AFq9FYKMsaLHMEq6W8WIQplS93Oljpn5OKn5dExLHRteMqb1WrtM9S17 7N/ak5K9okTDPYo+vEhhXDzF4XmbxIqLbKQl0nAmB3uY3kiJBddpn39l X-Gm-Gg: AYBFou3A6BcGVGy+QaZL3OI5VkE0ux19LtTJ2DK8LsjbEAUIqy0Iz0NFW/e3Mm3CsR+ XsgU9ysyFL02xhHwMmWbCrHJbDpQBON8DRd9HZbDsMHebofrw7tFvP52bEAvR3W2+9KnvTS0Z8T +8tsj4BDFz+NHxjku8qxhydm/xHRqO85pux8b5f3UDWfy29bYFPfSHqAqwoSDhEghhO53Xp20QT NMfWrjK5gXdxIn+JwyygtNhj7pHqLvkVwV4JtBh1uRzXe3MZwNvzmZ08Hqsg99kMW0TAO+f/pTp NUEUpOYks/o9v+HG/bi0FoGNTQKO6hbbvcVJpSAjVDPpwM1kUR3uHQcf+kt3P9oH4dAfWUjaiNg efby1dw7rJxJrHoMwJ6Da6lTWB1Wc9Cm4ZDZRLdwd/QLSvFc719T8FPcRdhj9boL6ZxMTGNzwGO NQVA7XH+vptRqFdRGlRctbiriTGiOmxWdFxtKzjw6qRkpARoIjqm55sZRevX0I7Q9/lIrYbjWNY 4T6amOLym2uUNUg7NtnNA== X-Received: by 2002:a17:902:d512:b0:2e9:3c24:999 with SMTP id d9443c01a7336-2e9a6c0de51mr23081545ad.40.1792234999087; Sat, 17 Oct 2026 04:03:19 -0700 (PDT) Received: from x1c ([2405:9800:b670:b64b:7c65:ff3e:80ba:b06]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2e97e804dd9sm20559955ad.16.2026.10.17.04.03.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 17 Oct 2026 04:03:18 -0700 (PDT) From: Tharit Tangkijwanichakul To: Paolo Bonzini , Sean Christopherson Cc: Shuah Khan , Marc Zyngier , Oliver Upton , Fuad Tabba , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel-mentees@lists.linux.dev, skhan@linuxfoundation.org, me@brighamcampbell.com, jkoolstra@xs4all.nl, Tharit Tangkijwanichakul Subject: [PATCH 4/5] KVM: selftests: Reserve memslot 1 for the ucall MMIO address Date: Sat, 17 Oct 2026 18:02:12 +0700 Message-ID: <20261017110213.46199-5-tharitt97@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261017110213.46199-1-tharitt97@gmail.com> References: <20261017110213.46199-1-tharitt97@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Back the ucall MMIO address with a read-only region in slot 1 when KVM_CAP_READONLY_MEM is available. Writes still exit as MMIO, while overlapping memslot creation is rejected. Start test memslots at slot 2, leaving slot 1 reserved by convention even when read-only memory is unsupported. Signed-off-by: Tharit Tangkijwanichakul --- .../testing/selftests/kvm/include/kvm_util.h | 2 +- tools/testing/selftests/kvm/lib/kvm_util.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h index 759d604d44ce..4dbb2ef332fc 100644 --- a/tools/testing/selftests/kvm/include/kvm_util.h +++ b/tools/testing/selftests/kvm/include/kvm_util.h @@ -30,7 +30,7 @@ #define KVM_DEV_PATH "/dev/kvm" #define KVM_MAX_VCPUS 512 -#define TEST_MEM_SLOT_BASE 1 +#define TEST_MEM_SLOT_BASE 2 #define NSEC_PER_SEC 1000000000L diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c index 9ddc047d5c27..73e28814a226 100644 --- a/tools/testing/selftests/kvm/lib/kvm_util.c +++ b/tools/testing/selftests/kvm/lib/kvm_util.c @@ -20,6 +20,7 @@ #include #define KVM_UTIL_MIN_PFN 2 +#define KVM_UCALL_MEMSLOT 1 u32 kvm_random_seed; struct kvm_random_state kvm_rng; @@ -492,6 +493,7 @@ struct kvm_vm *__vm_create(struct vm_shape shape, u32 nr_runnable_vcpus, struct userspace_mem_region *slot0; struct kvm_vm *vm; int i, flags; + gpa_t mmio_gpa; kvm_set_files_rlimit(nr_runnable_vcpus); @@ -514,14 +516,19 @@ struct kvm_vm *__vm_create(struct vm_shape shape, u32 nr_runnable_vcpus, kvm_vm_elf_load(vm, program_invocation_name); - /* - * TODO: Add proper defines to protect the library's memslots, and then - * carve out memslot1 for the ucall MMIO address. KVM treats writes to - * read-only memslots as MMIO, and creating a read-only memslot for the - * MMIO region would prevent silently clobbering the MMIO region. + /* KVM treats writes to read-only memslots as MMIO, and creating + * a read-only memslot for the MMIO region would prevent silently + * clobbering the MMIO region. */ slot0 = memslot2region(vm, 0); - ucall_init(vm, slot0->region.guest_phys_addr + slot0->region.memory_size); + mmio_gpa = slot0->region.guest_phys_addr + slot0->region.memory_size; + ucall_init(vm, mmio_gpa); + + if (vm_check_cap(vm, KVM_CAP_READONLY_MEM)) + vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, + mmio_gpa, KVM_UCALL_MEMSLOT, + vm_adjust_num_guest_pages(vm->mode, 1), + KVM_MEM_READONLY); if (kvm_random_seed != last_kvm_seed) kvm_seed_rng(kvm_random_seed); -- 2.53.0