From a603002eea8213eec5211be5a85db8340aea06d0 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 22 Jun 2022 08:38:36 +0200 Subject: virtio: replace restricted mem access flag with callback 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 Tested-by: Oleksandr Tyshchenko # Arm64 guest using Xen Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20220622063838.8854-2-jgross@suse.com Signed-off-by: Juergen Gross --- include/linux/platform-feature.h | 6 +----- include/linux/virtio_anchor.h | 19 +++++++++++++++++++ include/xen/xen.h | 4 ++-- 3 files changed, 22 insertions(+), 7 deletions(-) create mode 100644 include/linux/virtio_anchor.h (limited to 'include') diff --git a/include/linux/platform-feature.h b/include/linux/platform-feature.h index b2f48be999fa..6ed859928b97 100644 --- a/include/linux/platform-feature.h +++ b/include/linux/platform-feature.h @@ -6,11 +6,7 @@ #include /* 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) 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 = 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 *vec1, extern u64 xen_saved_max_mem_size; #endif -#include +#include 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); } #ifdef CONFIG_XEN_UNPOPULATED_ALLOC -- cgit v1.2.3 From a870544ca9d215449e91ebc01e35d80b23151c78 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 22 Jun 2022 08:38:37 +0200 Subject: kernel: remove platform_has() infrastructure The only use case of the platform_has() infrastructure has been removed again, so remove the whole feature. Signed-off-by: Juergen Gross Tested-by: Oleksandr Tyshchenko # Arm64 guest using Xen Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20220622063838.8854-3-jgross@suse.com Signed-off-by: Juergen Gross --- MAINTAINERS | 8 -------- include/asm-generic/Kbuild | 1 - include/asm-generic/platform-feature.h | 8 -------- include/linux/platform-feature.h | 15 --------------- kernel/Makefile | 2 +- kernel/platform-feature.c | 27 --------------------------- 6 files changed, 1 insertion(+), 60 deletions(-) delete mode 100644 include/asm-generic/platform-feature.h delete mode 100644 include/linux/platform-feature.h delete mode 100644 kernel/platform-feature.c (limited to 'include') diff --git a/MAINTAINERS b/MAINTAINERS index 64379c699903..c173a580ff77 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15953,14 +15953,6 @@ S: Maintained F: Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml F: drivers/iio/chemical/pms7003.c -PLATFORM FEATURE INFRASTRUCTURE -M: Juergen Gross -S: Maintained -F: arch/*/include/asm/platform-feature.h -F: include/asm-generic/platform-feature.h -F: include/linux/platform-feature.h -F: kernel/platform-feature.c - PLDMFW LIBRARY M: Jacob Keller S: Maintained diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild index 8e47d483b524..302506bbc2a4 100644 --- a/include/asm-generic/Kbuild +++ b/include/asm-generic/Kbuild @@ -44,7 +44,6 @@ mandatory-y += msi.h mandatory-y += pci.h mandatory-y += percpu.h mandatory-y += pgalloc.h -mandatory-y += platform-feature.h mandatory-y += preempt.h mandatory-y += rwonce.h mandatory-y += sections.h diff --git a/include/asm-generic/platform-feature.h b/include/asm-generic/platform-feature.h deleted file mode 100644 index 4b0af3d51588..000000000000 --- a/include/asm-generic/platform-feature.h +++ /dev/null @@ -1,8 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_GENERIC_PLATFORM_FEATURE_H -#define _ASM_GENERIC_PLATFORM_FEATURE_H - -/* Number of arch specific feature flags. */ -#define PLATFORM_ARCH_FEAT_N 0 - -#endif /* _ASM_GENERIC_PLATFORM_FEATURE_H */ diff --git a/include/linux/platform-feature.h b/include/linux/platform-feature.h deleted file mode 100644 index 6ed859928b97..000000000000 --- a/include/linux/platform-feature.h +++ /dev/null @@ -1,15 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _PLATFORM_FEATURE_H -#define _PLATFORM_FEATURE_H - -#include -#include - -/* The platform features are starting with the architecture specific ones. */ -#define PLATFORM_FEAT_N (0 + PLATFORM_ARCH_FEAT_N) - -void platform_set(unsigned int feature); -void platform_clear(unsigned int feature); -bool platform_has(unsigned int feature); - -#endif /* _PLATFORM_FEATURE_H */ diff --git a/kernel/Makefile b/kernel/Makefile index a7e1f49ab2b3..318789c728d3 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -7,7 +7,7 @@ obj-y = fork.o exec_domain.o panic.o \ cpu.o exit.o softirq.o resource.o \ sysctl.o capability.o ptrace.o user.o \ signal.o sys.o umh.o workqueue.o pid.o task_work.o \ - extable.o params.o platform-feature.o \ + extable.o params.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ async.o range.o smpboot.o ucount.o regset.o diff --git a/kernel/platform-feature.c b/kernel/platform-feature.c deleted file mode 100644 index cb6a6c3e4fed..000000000000 --- a/kernel/platform-feature.c +++ /dev/null @@ -1,27 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -#include -#include -#include -#include - -#define PLATFORM_FEAT_ARRAY_SZ BITS_TO_LONGS(PLATFORM_FEAT_N) -static unsigned long __read_mostly platform_features[PLATFORM_FEAT_ARRAY_SZ]; - -void platform_set(unsigned int feature) -{ - set_bit(feature, platform_features); -} -EXPORT_SYMBOL_GPL(platform_set); - -void platform_clear(unsigned int feature) -{ - clear_bit(feature, platform_features); -} -EXPORT_SYMBOL_GPL(platform_clear); - -bool platform_has(unsigned int feature) -{ - return test_bit(feature, platform_features); -} -EXPORT_SYMBOL_GPL(platform_has); -- cgit v1.2.3 From 251e90e7e346a23742b90e2c4db19d322e071d99 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 22 Jun 2022 08:38:38 +0200 Subject: xen: don't require virtio with grants for non-PV guests 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 guest using Xen Reviewed-by: Stefano Stabellini Link: https://lore.kernel.org/r/20220622063838.8854-4-jgross@suse.com Signed-off-by: Juergen Gross --- 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(-) (limited to 'include') 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 #include @@ -443,7 +444,8 @@ static int __init xen_guest_init(void) if (!xen_domain()) return 0; - xen_set_restricted_virtio_memory_access(); + if (IS_ENABLED(CONFIG_XEN_VIRTIO)) + virtio_set_mem_acc_cb(xen_virtio_mem_acc); 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 #include #include @@ -195,7 +196,8 @@ static void __init xen_hvm_guest_init(void) if (xen_pv_domain()) return; - xen_set_restricted_virtio_memory_access(); + if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); init_hvm_pv_info(); 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 #include #include @@ -109,7 +110,9 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 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); populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP)); 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 If in doubt, say n. +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; } +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 device *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 */ #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 *vec1, extern u64 xen_saved_max_mem_size; #endif -#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); -- cgit v1.2.3