From nobody Mon Sep 29 21:15:50 2025 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 2C3F1C00140 for ; Tue, 16 Aug 2022 00:39:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245335AbiHPAjA (ORCPT ); Mon, 15 Aug 2022 20:39:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351888AbiHPAge (ORCPT ); Mon, 15 Aug 2022 20:36:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A554518A8F9; Mon, 15 Aug 2022 13:37:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A70E261232; Mon, 15 Aug 2022 20:37:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96B9AC433C1; Mon, 15 Aug 2022 20:37:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660595878; bh=YTiMFhoSMMnGNTHiEsgFEmAmD1SPaL3yjJsXjV8eRAs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TBWXYBV7enf5Z5dcD7IlmwH/qsvMKHvZ3xSZu984xtkFbWrqktPaYpddE1zGu3Ae6 UgXKnzVvurq6H9ss4hguc6sOV6GYvAeW2XBVeDBkbBtwfct6xSNq3xORcs70X6nze8 Qm2GXTMRpK1Q/xY3MTZuOZ1f8u9AB3Lff1AbKjA0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Viresh Kumar , Juergen Gross , Oleksandr Tyshchenko , Stefano Stabellini , Sasha Levin Subject: [PATCH 5.19 0871/1157] xen: dont require virtio with grants for non-PV guests Date: Mon, 15 Aug 2022 20:03:47 +0200 Message-Id: <20220815180514.310806817@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Juergen Gross [ Upstream commit 251e90e7e346a23742b90e2c4db19d322e071d99 ] Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen grant mappings") introduced a new requirement for using virtio devices: the backend now needs to support the VIRTIO_F_ACCESS_PLATFORM feature. This is an undue requirement for non-PV guests, as those can be operated with existing backends without any problem, as long as those backends are running in dom0. Per default allow virtio devices without grant support for non-PV guests. On Arm require VIRTIO_F_ACCESS_PLATFORM for devices having been listed in the device tree to use grants. Add a new config item to always force use of grants for virtio. Fixes: fa1f57421e0b ("xen/virtio: Enable restricted memory access using Xen= grant mappings") Reported-by: Viresh Kumar Signed-off-by: Juergen Gross Reviewed-by: Oleksandr Tyshchenko Tested-by: Oleksandr Tyshchenko # Arm64 gue= st using Xen Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20220622063838.8854-4-jgross@suse.com Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- arch/arm/xen/enlighten.c | 4 +++- arch/x86/xen/enlighten_hvm.c | 4 +++- arch/x86/xen/enlighten_pv.c | 5 ++++- drivers/xen/Kconfig | 9 +++++++++ drivers/xen/grant-dma-ops.c | 10 ++++++++++ include/xen/xen-ops.h | 9 +++++++++ include/xen/xen.h | 8 -------- 7 files changed, 38 insertions(+), 11 deletions(-) diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 1f9c3ba32833..93c8ccbf2982 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -34,6 +34,7 @@ #include #include #include +#include =20 #include =20 @@ -443,7 +444,8 @@ static int __init xen_guest_init(void) if (!xen_domain()) return 0; =20 - xen_set_restricted_virtio_memory_access(); + if (IS_ENABLED(CONFIG_XEN_VIRTIO)) + virtio_set_mem_acc_cb(xen_virtio_mem_acc); =20 if (!acpi_disabled) xen_acpi_guest_init(); diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index 8b71b1dd7639..28762f800596 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -4,6 +4,7 @@ #include #include #include +#include =20 #include #include @@ -195,7 +196,8 @@ static void __init xen_hvm_guest_init(void) if (xen_pv_domain()) return; =20 - xen_set_restricted_virtio_memory_access(); + if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); =20 init_hvm_pv_info(); =20 diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 70fb2ea85e90..0ed2e487a693 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -31,6 +31,7 @@ #include #include #include +#include =20 #include #include @@ -109,7 +110,9 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc= ); =20 static void __init xen_pv_init_platform(void) { - xen_set_restricted_virtio_memory_access(); + /* PV guests can't operate virtio devices without grants. */ + if (IS_ENABLED(CONFIG_XEN_VIRTIO)) + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); =20 populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP)); =20 diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index bfd5f4f706bc..a65bd92121a5 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -355,4 +355,13 @@ config XEN_VIRTIO =20 If in doubt, say n. =20 +config XEN_VIRTIO_FORCE_GRANT + bool "Require Xen virtio support to use grants" + depends on XEN_VIRTIO + help + Require virtio for Xen guests to use grant mappings. + This will avoid the need to give the backend the right to map all + of the guest memory. This will need support on the backend side + (e.g. qemu or kernel, depending on the virtio device types used). + endmenu diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index fc0142484001..8973fc1e9ccc 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include #include @@ -287,6 +289,14 @@ bool xen_is_grant_dma_device(struct device *dev) return has_iommu; } =20 +bool xen_virtio_mem_acc(struct virtio_device *dev) +{ + if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) + return true; + + return xen_is_grant_dma_device(dev->dev.parent); +} + void xen_grant_setup_dma_ops(struct device *dev) { struct xen_grant_dma_data *data; diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h index 80546960f8b7..dae0f350c678 100644 --- a/include/xen/xen-ops.h +++ b/include/xen/xen-ops.h @@ -5,6 +5,7 @@ #include #include #include +#include #include #include #include @@ -217,6 +218,7 @@ static inline void xen_preemptible_hcall_end(void) { } #ifdef CONFIG_XEN_GRANT_DMA_OPS void xen_grant_setup_dma_ops(struct device *dev); bool xen_is_grant_dma_device(struct device *dev); +bool xen_virtio_mem_acc(struct virtio_device *dev); #else static inline void xen_grant_setup_dma_ops(struct device *dev) { @@ -225,6 +227,13 @@ static inline bool xen_is_grant_dma_device(struct devi= ce *dev) { return false; } + +struct virtio_device; + +static inline bool xen_virtio_mem_acc(struct virtio_device *dev) +{ + return false; +} #endif /* CONFIG_XEN_GRANT_DMA_OPS */ =20 #endif /* INCLUDE_XEN_OPS_H */ diff --git a/include/xen/xen.h b/include/xen/xen.h index ac5a144c6a65..a99bab817523 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -52,14 +52,6 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec= 1, extern u64 xen_saved_max_mem_size; #endif =20 -#include - -static inline void xen_set_restricted_virtio_memory_access(void) -{ - if (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain()) - virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); -} - #ifdef CONFIG_XEN_UNPOPULATED_ALLOC int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages= ); void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages= ); --=20 2.35.1