From patchwork Thu Mar 16 00:30:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ackerley Tng X-Patchwork-Id: 13176865 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 0DD5BC7619A for ; Thu, 16 Mar 2023 00:32:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233299AbjCPAcC (ORCPT ); Wed, 15 Mar 2023 20:32:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233126AbjCPAbm (ORCPT ); Wed, 15 Mar 2023 20:31:42 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7325EA3B75 for ; Wed, 15 Mar 2023 17:31:22 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id s15-20020a170902ea0f00b0019d0c7a83dfso15280plg.14 for ; Wed, 15 Mar 2023 17:31:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678926680; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=JjmIOJvjUEG2+4aovgmSBlRBGRP0JRLKbOkhR3o7e/I=; b=XWGmJ9JAs9QizM49LznB/3WeGWT9Pc+PU89wCd8j/FUtVE5mMn/ax/bL088f1qtOz1 RFmCWBaiH29nU9Rm1KEJYwwbJN+AkVaHOxnJG89ZrDJuTFkTNXO5WvuZG2ISNDllw0uo fSjaUkPVuesviWcTzk98UxYatwmpd417x6c+02nHUCPhFRDc3jObfLW3h3zTrxlqgUMt LSd6LeHzPnNB0IV8pPZgCTjW0bYxKCuKc0IBsjiwto4vhAFiBAjpHsDO9Qt092Ms2tAr DgVpYe+MAJleDmnTkKW5CLiYIwwbNbMGX4Gf9ND5AcxA8F5WN4Z2xDh5NS+5PrMXSWp9 XSmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678926680; 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=JjmIOJvjUEG2+4aovgmSBlRBGRP0JRLKbOkhR3o7e/I=; b=GbkUoB67Cm4TUYjzWToyalWGdiCb6XPBFVKtkhDAFN9CUOEuNqCi/X69dypyovshxv aQpYy5mirD/HxS15HnldAfFCY8VdDicih2AoC5a8bDzUKHF6+MZKGRMLc0IDmVaq0EZ1 3EEHO0KxxCa4s29U5MkusSp4Nfv9itYRJ54zTde3yf1sQhsKEWC0XQe/mB5zXAsSWmjY okSiV99HQfwHhAGt3vrSEmmezx23LKrwM4hg+SYq7wRx+xHedzjyW5Ehrb/MoTjAwL6N SveTgTxDnNLHL39lJ0VZbSff6WbmjdEda6sUhnmr8SmPtAbvJxJvvOCELGmYsyppKrnN 7KcQ== X-Gm-Message-State: AO0yUKX3hDw8UCnHwiS9AdE+LZC35wqIMcfNPfr96fa+UiSfywadeWYD M8eO74upyyBwX4huwwVUDXdvj1kVh21SGAOhbaWrYYx3LVbFiRs7i1TuiRNdS6y6H3dwOTx0+3z EHa0vky/TLwbtTc/f8mzcKQbNUcYrnGq1QUr90Mjs63wbR1nHLEyi5tk1K2X27aTtll2SltU= X-Google-Smtp-Source: AK7set+j36PrTQ1uWKwZ/ZTMviUfrC3nfQJHH3bSUBCARqM/YyB/PYWAqeXRAUTM8xOy7rllnybTZtBO0uvKhOtP8A== X-Received: from ackerleytng-cloudtop.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1f5f]) (user=ackerleytng job=sendgmr) by 2002:a17:902:e5cb:b0:1a0:4346:d43e with SMTP id u11-20020a170902e5cb00b001a04346d43emr595748plf.11.1678926680301; Wed, 15 Mar 2023 17:31:20 -0700 (PDT) Date: Thu, 16 Mar 2023 00:30:56 +0000 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.40.0.rc2.332.ga46443480c-goog Message-ID: <48490641ce981c31ea58c11ad478ff85cd0dd156.1678926164.git.ackerleytng@google.com> Subject: [RFC PATCH 03/10] KVM: selftests: Test that VM private memory should not be readable from host From: Ackerley Tng To: kvm@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, qemu-devel@nongnu.org Cc: aarcange@redhat.com, ak@linux.intel.com, akpm@linux-foundation.org, arnd@arndb.de, bfields@fieldses.org, bp@alien8.de, chao.p.peng@linux.intel.com, corbet@lwn.net, dave.hansen@intel.com, david@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, hpa@zytor.com, hughd@google.com, jlayton@kernel.org, jmattson@google.com, joro@8bytes.org, jun.nakajima@intel.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, luto@kernel.org, mail@maciej.szmigiero.name, mhocko@suse.com, michael.roth@amd.com, mingo@redhat.com, naoya.horiguchi@nec.com, pbonzini@redhat.com, qperret@google.com, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, tabba@google.com, tglx@linutronix.de, vannapurve@google.com, vbabka@suse.cz, vkuznets@redhat.com, wanpengli@tencent.com, wei.w.wang@intel.com, x86@kernel.org, yu.c.zhang@linux.intel.com, Ackerley Tng Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org After VM memory is remapped as private memory and guest has written to private memory, request the host to read the corresponding hva for that private memory. The host should not be able to read the value in private memory. This selftest shows that private memory contents of the guest are not accessible to host userspace via the HVA. Signed-off-by: Ackerley Tng --- .../kvm/x86_64/private_mem_conversions_test.c | 54 ++++++++++++++++--- 1 file changed, 48 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c index ef9894340a2b..f2c1e4450b0e 100644 --- a/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c +++ b/tools/testing/selftests/kvm/x86_64/private_mem_conversions_test.c @@ -47,6 +47,16 @@ static void memcmp_h(uint8_t *mem, uint8_t pattern, size_t size) pattern, i, mem[i]); } +static void memcmp_ne_h(uint8_t *mem, uint8_t pattern, size_t size) +{ + size_t i; + + for (i = 0; i < size; i++) + TEST_ASSERT(mem[i] != pattern, + "Expected not to find 0x%x at offset %lu but got 0x%x", + pattern, i, mem[i]); +} + /* * Run memory conversion tests with explicit conversion: * Execute KVM hypercall to map/unmap gpa range which will cause userspace exit @@ -64,8 +74,14 @@ static void memcmp_h(uint8_t *mem, uint8_t pattern, size_t size) #define GUEST_STAGE(o, s) { .offset = o, .size = s } -#define GUEST_SYNC4(gpa, size, current_pattern, new_pattern) \ - ucall(UCALL_SYNC, 4, gpa, size, current_pattern, new_pattern) +#define UCALL_RW_SHARED (0xca11 - 0) +#define UCALL_R_PRIVATE (0xca11 - 1) + +#define REQUEST_HOST_RW_SHARED(gpa, size, current_pattern, new_pattern) \ + ucall(UCALL_RW_SHARED, 4, gpa, size, current_pattern, new_pattern) + +#define REQUEST_HOST_R_PRIVATE(gpa, size, expected_pattern) \ + ucall(UCALL_R_PRIVATE, 3, gpa, size, expected_pattern) static void guest_code(void) { @@ -86,7 +102,7 @@ static void guest_code(void) /* Memory should be shared by default. */ memset((void *)DATA_GPA, ~init_p, DATA_SIZE); - GUEST_SYNC4(DATA_GPA, DATA_SIZE, ~init_p, init_p); + REQUEST_HOST_RW_SHARED(DATA_GPA, DATA_SIZE, ~init_p, init_p); memcmp_g(DATA_GPA, init_p, DATA_SIZE); for (i = 0; i < ARRAY_SIZE(stages); i++) { @@ -113,6 +129,12 @@ static void guest_code(void) kvm_hypercall_map_private(gpa, size); memset((void *)gpa, p2, size); + /* + * Host should not be able to read the values written to private + * memory + */ + REQUEST_HOST_R_PRIVATE(gpa, size, p2); + /* * Verify that the private memory was set to pattern two, and * that shared memory still holds the initial pattern. @@ -133,11 +155,20 @@ static void guest_code(void) continue; kvm_hypercall_map_shared(gpa + j, PAGE_SIZE); - GUEST_SYNC4(gpa + j, PAGE_SIZE, p1, p3); + REQUEST_HOST_RW_SHARED(gpa + j, PAGE_SIZE, p1, p3); memcmp_g(gpa + j, p3, PAGE_SIZE); } + /* + * Even-number pages are still mapped as private, host should + * not be able to read those values. + */ + for (j = 0; j < size; j += PAGE_SIZE) { + if (!((j >> PAGE_SHIFT) & 1)) + REQUEST_HOST_R_PRIVATE(gpa + j, PAGE_SIZE, p2); + } + /* * Convert the entire region back to shared, explicitly write * pattern three to fill in the even-number frames before @@ -145,7 +176,7 @@ static void guest_code(void) */ kvm_hypercall_map_shared(gpa, size); memset((void *)gpa, p3, size); - GUEST_SYNC4(gpa, size, p3, p4); + REQUEST_HOST_RW_SHARED(gpa, size, p3, p4); memcmp_g(gpa, p4, size); /* Reset the shared memory back to the initial pattern. */ @@ -209,7 +240,18 @@ static void test_mem_conversions(enum vm_mem_backing_src_type src_type) switch (get_ucall(vcpu, &uc)) { case UCALL_ABORT: REPORT_GUEST_ASSERT_4(uc, "%lx %lx %lx %lx"); - case UCALL_SYNC: { + case UCALL_R_PRIVATE: { + uint8_t *hva = addr_gpa2hva(vm, uc.args[0]); + uint64_t size = uc.args[1]; + + /* + * Try to read hva for private gpa from host, should not + * be able to read private data + */ + memcmp_ne_h(hva, uc.args[2], size); + break; + } + case UCALL_RW_SHARED: { uint8_t *hva = addr_gpa2hva(vm, uc.args[0]); uint64_t size = uc.args[1];