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Peter Anvin" , "Michael S. Tsirkin" , Jason Wang , Stefano Stabellini , Oleksandr Tyshchenko Subject: [PATCH v3 1/3] virtio: replace restricted mem access flag with callback Date: Wed, 22 Jun 2022 08:38:36 +0200 Message-Id: <20220622063838.8854-2-jgross@suse.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220622063838.8854-1-jgross@suse.com> References: <20220622063838.8854-1-jgross@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) X-ZM-MESSAGEID: 1655879964654100005 Content-Type: text/plain; charset="utf-8" Instead of having a global flag to require restricted memory access for all virtio devices, introduce a callback which can select that requirement on a per-device basis. For convenience add a common function returning always true, which can be used for use cases like SEV. Per default use a callback always returning false. As the callback needs to be set in early init code already, add a virtio anchor which is builtin in case virtio is enabled. Signed-off-by: Juergen Gross --- arch/s390/mm/init.c | 4 ++-- arch/x86/mm/mem_encrypt_amd.c | 4 ++-- drivers/virtio/Kconfig | 4 ++++ drivers/virtio/Makefile | 1 + drivers/virtio/virtio.c | 4 ++-- drivers/virtio/virtio_anchor.c | 18 ++++++++++++++++++ include/linux/platform-feature.h | 6 +----- include/linux/virtio_anchor.h | 19 +++++++++++++++++++ include/xen/xen.h | 4 ++-- 9 files changed, 51 insertions(+), 13 deletions(-) create mode 100644 drivers/virtio/virtio_anchor.c create mode 100644 include/linux/virtio_anchor.h diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 6a0ac00d5a42..4a154a084966 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -31,7 +31,6 @@ #include #include #include -#include #include #include #include @@ -48,6 +47,7 @@ #include #include #include +#include #include =20 pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir"); @@ -175,7 +175,7 @@ static void pv_init(void) if (!is_prot_virt_guest()) return; =20 - platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); =20 /* make sure bounce buffers are shared */ swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE); diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c index f6d038e2cd8e..97452688f99f 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -20,8 +20,8 @@ #include #include #include +#include #include -#include =20 #include #include @@ -245,7 +245,7 @@ void __init sev_setup_arch(void) swiotlb_adjust_size(size); =20 /* Set restricted memory access for virtio. */ - platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); } =20 static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret= _prot) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index a6dc8b5846fe..ce93966575a1 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -1,6 +1,10 @@ # SPDX-License-Identifier: GPL-2.0-only +config VIRTIO_ANCHOR + bool + config VIRTIO tristate + select VIRTIO_ANCHOR help This option is selected by any driver which implements the virtio bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index 0a82d0873248..8e98d24917cc 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_VIRTIO) +=3D virtio.o virtio_ring.o +obj-$(CONFIG_VIRTIO_ANCHOR) +=3D virtio_anchor.o obj-$(CONFIG_VIRTIO_PCI_LIB) +=3D virtio_pci_modern_dev.o obj-$(CONFIG_VIRTIO_PCI_LIB_LEGACY) +=3D virtio_pci_legacy_dev.o obj-$(CONFIG_VIRTIO_MMIO) +=3D virtio_mmio.o diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 6bace84ae37e..21e753fe1b50 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -2,10 +2,10 @@ #include #include #include +#include #include #include #include -#include #include =20 /* Unique numbering for virtio devices. */ @@ -174,7 +174,7 @@ static int virtio_features_ok(struct virtio_device *dev) =20 might_sleep(); =20 - if (platform_has(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS)) { + if (virtio_check_mem_acc_cb(dev)) { if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n"); diff --git a/drivers/virtio/virtio_anchor.c b/drivers/virtio/virtio_anchor.c new file mode 100644 index 000000000000..4d6a5d269b55 --- /dev/null +++ b/drivers/virtio/virtio_anchor.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include + +bool virtio_require_restricted_mem_acc(struct virtio_device *dev) +{ + return true; +} +EXPORT_SYMBOL_GPL(virtio_require_restricted_mem_acc); + +static bool virtio_no_restricted_mem_acc(struct virtio_device *dev) +{ + return false; +} + +bool (*virtio_check_mem_acc_cb)(struct virtio_device *dev) =3D + virtio_no_restricted_mem_acc; +EXPORT_SYMBOL_GPL(virtio_check_mem_acc_cb); diff --git a/include/linux/platform-feature.h b/include/linux/platform-feat= ure.h index b2f48be999fa..6ed859928b97 100644 --- a/include/linux/platform-feature.h +++ b/include/linux/platform-feature.h @@ -6,11 +6,7 @@ #include =20 /* The platform features are starting with the architecture specific ones.= */ - -/* Used to enable platform specific DMA handling for virtio devices. */ -#define PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS (0 + PLATFORM_ARCH_FEAT_N) - -#define PLATFORM_FEAT_N (1 + PLATFORM_ARCH_FEAT_N) +#define PLATFORM_FEAT_N (0 + PLATFORM_ARCH_FEAT_N) =20 void platform_set(unsigned int feature); void platform_clear(unsigned int feature); diff --git a/include/linux/virtio_anchor.h b/include/linux/virtio_anchor.h new file mode 100644 index 000000000000..432e6c00b3ca --- /dev/null +++ b/include/linux/virtio_anchor.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_VIRTIO_ANCHOR_H +#define _LINUX_VIRTIO_ANCHOR_H + +#ifdef CONFIG_VIRTIO_ANCHOR +struct virtio_device; + +bool virtio_require_restricted_mem_acc(struct virtio_device *dev); +extern bool (*virtio_check_mem_acc_cb)(struct virtio_device *dev); + +static inline void virtio_set_mem_acc_cb(bool (*func)(struct virtio_device= *)) +{ + virtio_check_mem_acc_cb =3D func; +} +#else +#define virtio_set_mem_acc_cb(func) do { } while (0) +#endif + +#endif /* _LINUX_VIRTIO_ANCHOR_H */ diff --git a/include/xen/xen.h b/include/xen/xen.h index 0780a81e140d..ac5a144c6a65 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -52,12 +52,12 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *ve= c1, extern u64 xen_saved_max_mem_size; #endif =20 -#include +#include =20 static inline void xen_set_restricted_virtio_memory_access(void) { if (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain()) - platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); } =20 #ifdef CONFIG_XEN_UNPOPULATED_ALLOC --=20 2.35.3