From: Juergen Gross jgross@suse.com
[ Upstream commit a603002eea8213eec5211be5a85db8340aea06d0 ]
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 jgross@suse.com Tested-by: Oleksandr Tyshchenko oleksandr_tyshchenko@epam.com # Arm64 guest using Xen Reviewed-by: Stefano Stabellini sstabellini@kernel.org Link: https://lore.kernel.org/r/20220622063838.8854-2-jgross@suse.com Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 <linux/cma.h> #include <linux/gfp.h> #include <linux/dma-direct.h> -#include <linux/platform-feature.h> #include <asm/processor.h> #include <linux/uaccess.h> #include <asm/pgalloc.h> @@ -48,6 +47,7 @@ #include <asm/kasan.h> #include <asm/dma-mapping.h> #include <asm/uv.h> +#include <linux/virtio_anchor.h> #include <linux/virtio_config.h>
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;
- platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
/* 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 <linux/bitops.h> #include <linux/dma-mapping.h> #include <linux/virtio_config.h> +#include <linux/virtio_anchor.h> #include <linux/cc_platform.h> -#include <linux/platform-feature.h>
#include <asm/tlbflush.h> #include <asm/fixmap.h> @@ -245,7 +245,7 @@ void __init sev_setup_arch(void) swiotlb_adjust_size(size);
/* Set restricted memory access for virtio. */ - platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); + virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc); }
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 e1556d2a355a..56c77f63cd22 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-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o +obj-$(CONFIG_VIRTIO_ANCHOR) += virtio_anchor.o obj-$(CONFIG_VIRTIO_PCI_LIB) += virtio_pci_modern_dev.o obj-$(CONFIG_VIRTIO_PCI_LIB_LEGACY) += virtio_pci_legacy_dev.o obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 7deeed30d1f3..14c142d77fba 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -2,10 +2,10 @@ #include <linux/virtio.h> #include <linux/spinlock.h> #include <linux/virtio_config.h> +#include <linux/virtio_anchor.h> #include <linux/module.h> #include <linux/idr.h> #include <linux/of.h> -#include <linux/platform-feature.h> #include <uapi/linux/virtio_ids.h>
/* Unique numbering for virtio devices. */ @@ -174,7 +174,7 @@ static int virtio_features_ok(struct virtio_device *dev)
might_sleep();
- 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 <linux/virtio.h> +#include <linux/virtio_anchor.h> + +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) = + 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-feature.h index b2f48be999fa..6ed859928b97 100644 --- a/include/linux/platform-feature.h +++ b/include/linux/platform-feature.h @@ -6,11 +6,7 @@ #include <asm/platform-feature.h>
/* 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 <linux/platform-feature.h> +#include <linux/virtio_anchor.h>
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