From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3D40DFF4946 for ; Mon, 30 Mar 2026 06:22:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=JRGlqTUddNs22qbjK1XF9AytOTARdjde3qWaPPuWarI=; b=R1d29IfWhPV2TWOW3yU5FKRMUl kNBfUqqmdzax9zx7yfAc4A/Y9Ixwq9+M8WSqXzKjR3LpUJ++8Wl0lojjT7ZkTmAAEESvwVBY9xTbZ VEHeYIvNBT9doilqttcUlx5opzsREUmEeIgFc2EEs6KFkVfwo8XBtnUZb0C2pz+dkk2lOpXCrQbWS iEFEbFhBpitRmo5l0fSbVz7ziqlXz7RsgEtKmmjGJ4khhC2S14UYHNGddqo852d9LrKBthcetThIO iqUWfUAJGhmnJA+06QpF0zMVA7A5LYlxtBSTpxtPoKcB1L7Ia8eWZgjL3c4PFwrCTBkcBz8V/W78K rjMo2S0Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w760x-0000000Ag7o-1KIG; Mon, 30 Mar 2026 06:22:19 +0000 Received: from out-176.mta1.migadu.com ([95.215.58.176]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w760t-0000000Ag6D-1FEp for linux-arm-kernel@lists.infradead.org; Mon, 30 Mar 2026 06:22:17 +0000 Message-ID: <0064952b-048c-455d-ad89-e27e5cb82591@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1774851728; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JRGlqTUddNs22qbjK1XF9AytOTARdjde3qWaPPuWarI=; b=ITBmfkdGvwuPDXnsffYC3RL1CaOmCF/2VlOTHdKT+Q7ImF10cXOMIoVaLLRIU4blXOt6tP duQCcmk2g36LuwcQWBgCNhYQYhVZf0XcLdzLJABnsHxs6Gkks4lvw9jpYB4A7jo5ZZy2Hs 0Pk3+FiE2FReGdaXwbt6hKscxnFc+Cc= Date: Mon, 30 Mar 2026 14:21:50 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v17 24/24] KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory To: Sean Christopherson Cc: Paolo Bonzini , Marc Zyngier , Oliver Upton , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Gavin Shan , Shivank Garg , Vlastimil Babka , Xiaoyao Li , David Hildenbrand , Fuad Tabba , Ackerley Tng , Tao Chan , James Houghton References: <20250729225455.670324-1-seanjc@google.com> <20250729225455.670324-25-seanjc@google.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zenghui Yu In-Reply-To: <20250729225455.670324-25-seanjc@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260329_232216_264069_D25F9FEF X-CRM114-Status: GOOD ( 20.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 7/30/25 6:54 AM, Sean Christopherson wrote: > Add a guest_memfd testcase to verify that a vCPU can fault-in guest_memfd > memory that supports mmap(), but that is not currently mapped into host > userspace and/or has a userspace address (in the memslot) that points at > something other than the target guest_memfd range. Mapping guest_memfd > memory into the guest is supposed to operate completely independently from > any userspace mappings. > > Signed-off-by: Sean Christopherson > --- > .../testing/selftests/kvm/guest_memfd_test.c | 64 +++++++++++++++++++ > 1 file changed, 64 insertions(+) > > diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c > index 088053d5f0f5..b86bf89a71e0 100644 > --- a/tools/testing/selftests/kvm/guest_memfd_test.c > +++ b/tools/testing/selftests/kvm/guest_memfd_test.c > @@ -13,6 +13,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -21,6 +22,7 @@ > > #include "kvm_util.h" > #include "test_util.h" > +#include "ucall_common.h" > > static void test_file_read_write(int fd) > { > @@ -298,6 +300,66 @@ static void test_guest_memfd(unsigned long vm_type) > kvm_vm_free(vm); > } > > +static void guest_code(uint8_t *mem, uint64_t size) > +{ > + size_t i; > + > + for (i = 0; i < size; i++) > + __GUEST_ASSERT(mem[i] == 0xaa, > + "Guest expected 0xaa at offset %lu, got 0x%x", i, mem[i]); > + > + memset(mem, 0xff, size); > + GUEST_DONE(); > +} > + > +static void test_guest_memfd_guest(void) > +{ > + /* > + * Skip the first 4gb and slot0. slot0 maps <1gb and is used to back > + * the guest's code, stack, and page tables, and low memory contains > + * the PCI hole and other MMIO regions that need to be avoided. > + */ > + const uint64_t gpa = SZ_4G; > + const int slot = 1; > + > + struct kvm_vcpu *vcpu; > + struct kvm_vm *vm; > + uint8_t *mem; > + size_t size; > + int fd, i; > + > + if (!kvm_has_cap(KVM_CAP_GUEST_MEMFD_MMAP)) > + return; > + > + vm = __vm_create_shape_with_one_vcpu(VM_SHAPE_DEFAULT, &vcpu, 1, guest_code); > + > + TEST_ASSERT(vm_check_cap(vm, KVM_CAP_GUEST_MEMFD_MMAP), > + "Default VM type should always support guest_memfd mmap()"); > + > + size = vm->page_size; > + fd = vm_create_guest_memfd(vm, size, GUEST_MEMFD_FLAG_MMAP); This test fails on arm64 when vm->page_size is 4k and host's page_size is 64k: [root@localhost kvm]# ./guest_memfd_test Random seed: 0x6b8b4567 __vm_create: mode='PA-bits:40, VA-bits:48, 4K pages' type='0', pages='660' ==== Test Assertion Failure ==== include/kvm_util.h:683: fd >= 0 pid=889 tid=889 errno=22 - Invalid argument 1 0x000000000040262b: vm_create_guest_memfd at kvm_util.h:683 2 (inlined by) test_guest_memfd_guest at guest_memfd_test.c:450 3 (inlined by) main at guest_memfd_test.c:491 4 0x00007fff8f56af3b: ?? ??:0 5 0x00007fff8f56b007: ?? ??:0 6 0x0000000000402a2f: _start at ??:? KVM_CREATE_GUEST_MEMFD failed, rc: -1 errno: 22 (Invalid argument) Thanks, Zenghui > + vm_set_user_memory_region2(vm, slot, KVM_MEM_GUEST_MEMFD, gpa, size, NULL, fd, 0); > + > + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); > + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); > + memset(mem, 0xaa, size); > + munmap(mem, size); > + > + virt_pg_map(vm, gpa, gpa); > + vcpu_args_set(vcpu, 2, gpa, size); > + vcpu_run(vcpu); > + > + TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_DONE); > + > + mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); > + TEST_ASSERT(mem != MAP_FAILED, "mmap() on guest_memfd failed"); > + for (i = 0; i < size; i++) > + TEST_ASSERT_EQ(mem[i], 0xff); > + > + close(fd); > + kvm_vm_free(vm); > +} > + > int main(int argc, char *argv[]) > { > unsigned long vm_types, vm_type; > @@ -314,4 +376,6 @@ int main(int argc, char *argv[]) > > for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types)) > test_guest_memfd(vm_type); > + > + test_guest_memfd_guest(); > }