From nobody Sat Feb 7 03:11:06 2026 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 D683AC43217 for ; Mon, 28 Nov 2022 22:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234589AbiK1W54 (ORCPT ); Mon, 28 Nov 2022 17:57:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234427AbiK1W5p (ORCPT ); Mon, 28 Nov 2022 17:57:45 -0500 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A27C1D331 for ; Mon, 28 Nov 2022 14:57:45 -0800 (PST) Received: by mail-pj1-x1049.google.com with SMTP id pi2-20020a17090b1e4200b0021834843687so12942610pjb.0 for ; Mon, 28 Nov 2022 14:57:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=xELzf4EoZMDlLUFpchpTMdst44hVrjj4VfJq2w9Ep4g=; b=tfGq1I9Ag4TRomwGArbD/e7Y8OTucyzeGIBpiuBA8HCvwovRyzZMr0jL1essdKJxRl AsLiTHBqMnFPfYFL6W6Gg7mrjwghkx+mm5CkL9sermoxxif5geNncKOnzhv9WJMna7+6 EPztlMnA0Oomg6EENpjW8lYY6HTV4pMsV6RsBaky6LIIuYQSC81VQlR7T/MBuaYTWxpQ f5UDgsfX+NOHM+75d9ZexrzlpgZuMggqW0WB5v/Wh074p4fD/QcK7Gu/EJn7qY53pFPB GawhLmEMkaB82ICjvMdzs3LpOgwabZXU5VPUQVxNfTlONzJDpAGPE3cFsxOXcyO0tlwn 4clQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=xELzf4EoZMDlLUFpchpTMdst44hVrjj4VfJq2w9Ep4g=; b=VjX9hLOnbfhY5H2/SLVONYdDelavIfJMYRCPPpG0c1qMAYAWwSWTiZbTU/e9GUV7Hm scuCMFDtVbYJipaxRBv+1Ou1E5MwnRvwSARiVcSM/JgAGDQjA8nVtg5evaJao42K3Bcc w38Ju87ae5QcDCV9912UOliTf4XZET+W6/c0dt5yBg0ZKXnEj82eFN4K0n65ucQcud+c tPklcmcXOBLFFnyhdfewEJnj24VKGZnlKUgSl1p7y6ixW3HFT8ImUhWwVmXsP236mCMK yGrE7Lv6NQ3Q05Za5wTGoVXhCO9dGFu73/vDxvUi7aYW3ZPKmga7A8XjF9D78LPaTy1n FEtg== X-Gm-Message-State: ANoB5pmt/K3wJNoMHxfR4ermMNd+Ks8/eoEnwdiX50N+6p9LbYG+nAzb OGokGIsNE8Eo7NZLJb5Izcq69FHxnjQ= X-Google-Smtp-Source: AA0mqf7XlYSOiBUAPxiV1JPp5qojEVpBxwXB4xMCDPs7V/2pUAuGBNrlhEa8A1+VJ8AZPriNzHDsDb7tf1Y= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:820c:b0:189:505b:73dd with SMTP id x12-20020a170902820c00b00189505b73ddmr26974391pln.143.1669676264666; Mon, 28 Nov 2022 14:57:44 -0800 (PST) Reply-To: Sean Christopherson Date: Mon, 28 Nov 2022 22:57:34 +0000 In-Reply-To: <20221128225735.3291648-1-seanjc@google.com> Mime-Version: 1.0 References: <20221128225735.3291648-1-seanjc@google.com> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog Message-ID: <20221128225735.3291648-4-seanjc@google.com> Subject: [PATCH v2 3/4] KVM: selftests: Disallow "get supported CPUID" before REQ_XCOMP_GUEST_PERM From: Sean Christopherson To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Lei Wang , Sean Christopherson Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Disallow using kvm_get_supported_cpuid() and thus caching KVM's supported CPUID info before enabling XSAVE-managed features that are off-by-default and must be enabled by ARCH_REQ_XCOMP_GUEST_PERM. Caching the supported CPUID before all XSAVE features are enabled can result in false negatives due to testing features that were cached before they were enabled. Signed-off-by: Sean Christopherson --- .../selftests/kvm/lib/x86_64/processor.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/tes= ting/selftests/kvm/lib/x86_64/processor.c index 23067465c035..1d3829e652e6 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -601,21 +601,24 @@ void vcpu_arch_free(struct kvm_vcpu *vcpu) free(vcpu->cpuid); } =20 +/* Do not use kvm_supported_cpuid directly except for validity checks. */ +static void *kvm_supported_cpuid; + const struct kvm_cpuid2 *kvm_get_supported_cpuid(void) { - static struct kvm_cpuid2 *cpuid; int kvm_fd; =20 - if (cpuid) - return cpuid; + if (kvm_supported_cpuid) + return kvm_supported_cpuid; =20 - cpuid =3D allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES); + kvm_supported_cpuid =3D allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES); kvm_fd =3D open_kvm_dev_path_or_exit(); =20 - kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, cpuid); + kvm_ioctl(kvm_fd, KVM_GET_SUPPORTED_CPUID, + (struct kvm_cpuid2 *)kvm_supported_cpuid); =20 close(kvm_fd); - return cpuid; + return kvm_supported_cpuid; } =20 static uint32_t __kvm_cpu_has(const struct kvm_cpuid2 *cpuid, @@ -684,6 +687,9 @@ void __vm_xsave_require_permission(int bit, const char = *name) .addr =3D (unsigned long) &bitmask }; =20 + TEST_ASSERT(!kvm_supported_cpuid, + "kvm_get_supported_cpuid() cannot be used before ARCH_REQ_XCOMP_GUES= T_PERM"); + kvm_fd =3D open_kvm_dev_path_or_exit(); rc =3D __kvm_ioctl(kvm_fd, KVM_GET_DEVICE_ATTR, &attr); close(kvm_fd); --=20 2.38.1.584.g0f3c55d4c2-goog