From: Juergen Gross jgross@suse.com
[ 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 viresh.kumar@linaro.org Signed-off-by: Juergen Gross jgross@suse.com Reviewed-by: Oleksandr Tyshchenko oleksandr_tyshchenko@epam.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/20220622063838.8854-4-jgross@suse.com Signed-off-by: Juergen Gross jgross@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 <linux/timekeeping.h> #include <linux/timekeeper_internal.h> #include <linux/acpi.h> +#include <linux/virtio_anchor.h>
#include <linux/mm.h>
@@ -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 <linux/cpu.h> #include <linux/kexec.h> #include <linux/memblock.h> +#include <linux/virtio_anchor.h>
#include <xen/features.h> #include <xen/events.h> @@ -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 <linux/gfp.h> #include <linux/edd.h> #include <linux/reboot.h> +#include <linux/virtio_anchor.h>
#include <xen/xen.h> #include <xen/events.h> @@ -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 <linux/of.h> #include <linux/pfn.h> #include <linux/xarray.h> +#include <linux/virtio_anchor.h> +#include <linux/virtio.h> #include <xen/xen.h> #include <xen/xen-ops.h> #include <xen/grant_table.h> @@ -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 <linux/percpu.h> #include <linux/notifier.h> #include <linux/efi.h> +#include <linux/virtio_anchor.h> #include <xen/features.h> #include <asm/xen/interface.h> #include <xen/interface/vcpu.h> @@ -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 <linux/virtio_anchor.h> - -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);