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authorJuergen Gross <jgross@suse.com>2022-06-22 08:38:38 +0200
committerJuergen Gross <jgross@suse.com>2022-08-01 07:43:03 +0200
commit251e90e7e346a23742b90e2c4db19d322e071d99 (patch)
treec4c3477288ae1ab03b0933fbeeaff78020c1b63f /drivers/xen
parenta870544ca9d215449e91ebc01e35d80b23151c78 (diff)
downloadlinux-251e90e7e346a23742b90e2c4db19d322e071d99.tar.bz2
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 <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>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/Kconfig9
-rw-r--r--drivers/xen/grant-dma-ops.c10
2 files changed, 19 insertions, 0 deletions
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;