From patchwork Fri Dec 9 01:53:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 632747 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53764C4332F for ; Fri, 9 Dec 2022 01:54:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229610AbiLIByK (ORCPT ); Thu, 8 Dec 2022 20:54:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230064AbiLIBxv (ORCPT ); Thu, 8 Dec 2022 20:53:51 -0500 Received: from out-149.mta0.migadu.com (out-149.mta0.migadu.com [IPv6:2001:41d0:1004:224b::95]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF97F950FE for ; Thu, 8 Dec 2022 17:53:42 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Oliver Upton , Paolo Bonzini , Shuah Khan , Nathan Chancellor , Nick Desaulniers , Tom Rix Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kvmarm@lists.linux.dev, Ricardo Koller , Sean Christopherson , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH v2 5/7] KVM: arm64: selftests: Don't identity map the ucall MMIO hole Date: Fri, 9 Dec 2022 01:53:04 +0000 Message-Id: <20221209015307.1781352-6-oliver.upton@linux.dev> In-Reply-To: <20221209015307.1781352-1-oliver.upton@linux.dev> References: <20221209015307.1781352-1-oliver.upton@linux.dev> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Currently the ucall MMIO hole is placed immediately after slot0, which is a relatively safe address in the PA space. However, it is possible that the same address has already been used for something else (like the guest program image) in the VA space. At least in my own testing, building the vgic_irq test with clang leads to the MMIO hole appearing underneath gicv3_ops. Stop identity mapping the MMIO hole and instead find an unused VA to map to it. Yet another subtle detail of the KVM selftests library is that virt_pg_map() does not update vm->vpages_mapped. Switch over to virt_map() instead to guarantee that the chosen VA isn't to something else. Signed-off-by: Oliver Upton --- tools/testing/selftests/kvm/lib/aarch64/ucall.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/aarch64/ucall.c b/tools/testing/selftests/kvm/lib/aarch64/ucall.c index 562c16dfbb00..f212bd8ab93d 100644 --- a/tools/testing/selftests/kvm/lib/aarch64/ucall.c +++ b/tools/testing/selftests/kvm/lib/aarch64/ucall.c @@ -14,11 +14,13 @@ static vm_vaddr_t *ucall_exit_mmio_addr; void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa) { - virt_pg_map(vm, mmio_gpa, mmio_gpa); + vm_vaddr_t mmio_gva = vm_vaddr_unused_gap(vm, vm->page_size, KVM_UTIL_MIN_VADDR); + + virt_map(vm, mmio_gva, mmio_gpa, 1); vm->ucall_mmio_addr = mmio_gpa; - write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gpa); + write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gva); } void ucall_arch_do_ucall(vm_vaddr_t uc)