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xen: don't require virtio with grants for non-PV guests

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Commit fa1f57421e ("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: fa1f57421e ("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>
This commit is contained in:
Juergen Gross
2022-06-22 08:38:38 +02:00
parent a870544ca9
commit 251e90e7e3
7 changed files with 38 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
include/xen/xen-ops.h
View File

@@ -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 */

8
include/xen/xen.h
View File

@@ -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);