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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 1F52AC4338F for ; Sat, 21 Aug 2021 12:08:15 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 8B67F61216 for ; Sat, 21 Aug 2021 12:08:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8B67F61216 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 182A94B1A1; Sat, 21 Aug 2021 08:08:14 -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 TC6UebEJUxfC; Sat, 21 Aug 2021 08:08:09 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 951DA4B1A4; Sat, 21 Aug 2021 08:08:09 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id DC1EF4B19F for ; Sat, 21 Aug 2021 08:08:08 -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 gLgBbbuj9Lm5 for ; Sat, 21 Aug 2021 08:08:04 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 44D984B176 for ; Sat, 21 Aug 2021 08:08:04 -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 14E7761215; Sat, 21 Aug 2021 12:08:03 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=hot-poop.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mHPn6-006Md6-Oa; Sat, 21 Aug 2021 13:08:00 +0100 From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH][kvmtool] virtio/pci: Correctly handle MSI-X masking while MSI-X is disabled Date: Sat, 21 Aug 2021 13:07:42 +0100 Message-Id: <20210821120742.855712-1-maz@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, kernel-team@android.com, Andre.Przywara@arm.com, alexandru.elisei@arm.com, tglx@linutronix.de, will@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: Andre Przywara , Thomas Gleixner , kernel-team@android.com, Will Deacon 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 Since Linux commit 7d5ec3d36123 ("PCI/MSI: Mask all unused MSI-X entries"), kvmtool segfaults when the guest boots and tries to disable all the MSI-X entries of a virtio device while MSI-X itself is disabled. What Linux does is seems perfectly correct. However, kvmtool uses a different decoding depending on whether MSI-X is enabled for this device or not. Which seems pretty wrong. Cure the problem by removing the check against MSI-X being enabled, and simplify the whole logic which looked a bit odd. With this, Linux is back booting as a kvmtool guest with MSI-X. Cc: Andre Przywara Cc: Alexandru Elisei Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Marc Zyngier --- include/kvm/virtio.h | 2 +- virtio/core.c | 12 ++++-------- virtio/pci.c | 7 ++----- 3 files changed, 7 insertions(+), 14 deletions(-) diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h index 3a311f54..7047d36f 100644 --- a/include/kvm/virtio.h +++ b/include/kvm/virtio.h @@ -166,7 +166,7 @@ u16 virt_queue__get_head_iov(struct virt_queue *vq, struct iovec iov[], u16 virt_queue__get_inout_iov(struct kvm *kvm, struct virt_queue *queue, struct iovec in_iov[], struct iovec out_iov[], u16 *in, u16 *out); -int virtio__get_dev_specific_field(int offset, bool msix, u32 *config_off); +int virtio__get_dev_specific_field(int offset, u32 *config_off); enum virtio_trans { VIRTIO_PCI, diff --git a/virtio/core.c b/virtio/core.c index 90a661d1..afb09e90 100644 --- a/virtio/core.c +++ b/virtio/core.c @@ -169,16 +169,12 @@ void virtio_exit_vq(struct kvm *kvm, struct virtio_device *vdev, memset(vq, 0, sizeof(*vq)); } -int virtio__get_dev_specific_field(int offset, bool msix, u32 *config_off) +int virtio__get_dev_specific_field(int offset, u32 *config_off) { - if (msix) { - if (offset < 4) - return VIRTIO_PCI_O_MSIX; - else - offset -= 4; - } + if (offset < 24) + return VIRTIO_PCI_O_MSIX; - *config_off = offset; + *config_off = offset - 24; return VIRTIO_PCI_O_CONFIG; } diff --git a/virtio/pci.c b/virtio/pci.c index eb91f512..2a6e41f1 100644 --- a/virtio/pci.c +++ b/virtio/pci.c @@ -112,9 +112,7 @@ static bool virtio_pci__specific_data_in(struct kvm *kvm, struct virtio_device * { u32 config_offset; struct virtio_pci *vpci = vdev->virtio; - int type = virtio__get_dev_specific_field(offset - 20, - virtio_pci__msix_enabled(vpci), - &config_offset); + int type = virtio__get_dev_specific_field(offset, &config_offset); if (type == VIRTIO_PCI_O_MSIX) { switch (offset) { case VIRTIO_MSI_CONFIG_VECTOR: @@ -208,8 +206,7 @@ static bool virtio_pci__specific_data_out(struct kvm *kvm, struct virtio_device struct virtio_pci *vpci = vdev->virtio; u32 config_offset, vec; int gsi; - int type = virtio__get_dev_specific_field(offset - 20, virtio_pci__msix_enabled(vpci), - &config_offset); + int type = virtio__get_dev_specific_field(offset, &config_offset); if (type == VIRTIO_PCI_O_MSIX) { switch (offset) { case VIRTIO_MSI_CONFIG_VECTOR: -- 2.30.2 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm