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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D7D0C433E1 for ; Fri, 29 May 2020 16:03:41 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 3388220897 for ; Fri, 29 May 2020 16:03:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="YcnFoBNw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3388220897 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E1D874B27F; Fri, 29 May 2020 12:03:40 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@kernel.org Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oBA8t1E5+p+8; Fri, 29 May 2020 12:03:39 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 0D4804B279; Fri, 29 May 2020 12:03:39 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 153EE4B21E for ; Fri, 29 May 2020 12:03:38 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6wStC3UEw442 for ; Fri, 29 May 2020 12:03:37 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 017BE4B25C for ; Fri, 29 May 2020 12:03:36 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1EA2520814; Fri, 29 May 2020 16:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590768215; bh=R6r5GkOAL3ZO4KyBEEK8jowTrzETCOs0VNAKSknUigQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YcnFoBNwGYCJ+0cE90hlmpyIwlOlpZaPDciH/QNLFsc1+flwoV/cQk/HDFiJFGepP WqXA+2j9c57PBLjwtboHBVxaCOh1+BEbDsdNpaIY5AhiSMJ4HnP3ykzcRHWnM0qFg1 OX1N/2u4YrzwnVbKzPSL5qKb6ujntP0wwHZW8+W4= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jehSD-00GJKc-Nk; Fri, 29 May 2020 17:01:54 +0100 From: Marc Zyngier To: Paolo Bonzini Subject: [PATCH 14/24] KVM: arm64: Make KVM_CAP_MAX_VCPUS compatible with the selected GIC version Date: Fri, 29 May 2020 17:01:11 +0100 Message-Id: <20200529160121.899083-15-maz@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200529160121.899083-1-maz@kernel.org> References: <20200529160121.899083-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: pbonzini@redhat.com, alexandru.elisei@arm.com, ascull@google.com, ardb@kernel.org, christoffer.dall@arm.com, dbrazdil@google.com, tabba@google.com, james.morse@arm.com, giangyi@amazon.com, zhukeqian1@huawei.com, mark.rutland@arm.com, suzuki.poulose@arm.com, will@kernel.org, yuzenghui@huawei.com, julien.thierry.kdev@gmail.com, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Will Deacon , Jiang Yi , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu KVM_CAP_MAX_VCPUS always return the maximum possible number of VCPUs, irrespective of the selected interrupt controller. This is pretty misleading for userspace that selects a GICv2 on a GICv3 system that supports v2 compat: It always gets a maximum of 512 VCPUs, even if the effective limit is 8. The 9th VCPU will fail to be created, which is unexpected as far as userspace is concerned. Fortunately, we already have the right information stashed in the kvm structure, and we can return it as requested. Reported-by: Ard Biesheuvel Signed-off-by: Marc Zyngier Tested-by: Alexandru Elisei Reviewed-by: Alexandru Elisei Link: https://lore.kernel.org/r/20200427141507.284985-1-maz@kernel.org --- arch/arm64/kvm/arm.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 0ea9a0266d9a..e01d44df98df 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -95,6 +95,11 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, return r; } +static int kvm_arm_default_max_vcpus(void) +{ + return vgic_present ? kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS; +} + /** * kvm_arch_init_vm - initializes a VM data structure * @kvm: pointer to the KVM struct @@ -128,8 +133,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.vmid.vmid_gen = 0; /* The maximum number of VCPUs is limited by the host's GIC model */ - kvm->arch.max_vcpus = vgic_present ? - kvm_vgic_get_max_vcpus() : KVM_MAX_VCPUS; + kvm->arch.max_vcpus = kvm_arm_default_max_vcpus(); return ret; out_free_stage2_pgd: @@ -204,10 +208,11 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = num_online_cpus(); break; case KVM_CAP_MAX_VCPUS: - r = KVM_MAX_VCPUS; - break; case KVM_CAP_MAX_VCPU_ID: - r = KVM_MAX_VCPU_ID; + if (kvm) + r = kvm->arch.max_vcpus; + else + r = kvm_arm_default_max_vcpus(); break; case KVM_CAP_MSI_DEVID: if (!kvm) -- 2.26.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm