[PATCH V4 4/8] xen/virtio: Enable restricted memory access using Xen grant mappings
From: Oleksandr Tyshchenko <hidden>
Date: 2022-06-02 19:24:37
Also in:
lkml, xen-devel
Subsystem:
arm port, the rest, x86 architecture (32-bit and 64-bit), xen hypervisor arm, xen hypervisor interface, xen hypervisor x86 · Maintainers:
Russell King, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Stefano Stabellini, Juergen Gross
From: Juergen Gross <jgross@suse.com>
In order to support virtio in Xen guests add a config option XEN_VIRTIO
enabling the user to specify whether in all Xen guests virtio should
be able to access memory via Xen grant mappings only on the host side.
Also set PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS feature from the guest
initialization code on Arm and x86 if CONFIG_XEN_VIRTIO is enabled.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
Changes V1 -> V2:
- new patch, split required changes from commit:
"[PATCH V1 3/6] xen/virtio: Add option to restrict memory access under Xen"
- rework according to new platform_has() infrastructure
Changes V2 -> V3:
- add Stefano's R-b
Changes V3 -> V4:
- add Boris' R-b
---
arch/arm/xen/enlighten.c | 2 ++
arch/x86/xen/enlighten_hvm.c | 2 ++
arch/x86/xen/enlighten_pv.c | 2 ++
drivers/xen/Kconfig | 11 +++++++++++
include/xen/xen.h | 8 ++++++++
5 files changed, 25 insertions(+)
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 07eb69f..1f9c3ba 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c@@ -443,6 +443,8 @@ static int __init xen_guest_init(void) if (!xen_domain()) return 0; + xen_set_restricted_virtio_memory_access(); + if (!acpi_disabled) xen_acpi_guest_init(); else
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 517a9d8..8b71b1d 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c@@ -195,6 +195,8 @@ static void __init xen_hvm_guest_init(void) if (xen_pv_domain()) return; + xen_set_restricted_virtio_memory_access(); + init_hvm_pv_info(); reserve_shared_info();
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index ca85d14..30d24fe 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c@@ -108,6 +108,8 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); static void __init xen_pv_init_platform(void) { + xen_set_restricted_virtio_memory_access(); + populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP)); set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 313a9127..a7bd8ce 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig@@ -339,4 +339,15 @@ config XEN_GRANT_DMA_OPS bool select DMA_OPS +config XEN_VIRTIO + bool "Xen virtio support" + depends on VIRTIO + select XEN_GRANT_DMA_OPS + help + Enable virtio support for running as Xen guest. Depending on the + guest type this will require special support on the backend side + (qemu or kernel, depending on the virtio device types used). + + If in doubt, say n. + endmenu
diff --git a/include/xen/xen.h b/include/xen/xen.h
index a99bab8..0780a81 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h@@ -52,6 +52,14 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, extern u64 xen_saved_max_mem_size; #endif +#include <linux/platform-feature.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); +} + #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);
--
2.7.4
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