Add basic support for virtio with grants on x86 by defaulting the
backend to be in dom0 in the case the guest kernel was built with
CONFIG_XEN_VIRTIO_FORCE_GRANT.
Juergen Gross (3):
xen/virtio: restructure xen grant dma setup
xen/virtio: use dom0 as default backend for
CONFIG_XEN_VIRTIO_FORCE_GRANT
xen/virtio: enable grant based virtio on x86
arch/x86/xen/enlighten_hvm.c | 2 +-
arch/x86/xen/enlighten_pv.c | 2 +-
drivers/xen/grant-dma-ops.c | 81 +++++++++++++++++++++++++-----------
include/xen/xen-ops.h | 1 +
4 files changed, 59 insertions(+), 27 deletions(-)
--
2.35.3
In order to prepare supporting other means than device tree for
setting up virtio devices under Xen, restructure the functions
xen_is_grant_dma_device() and xen_grant_setup_dma_ops() a little bit.
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/grant-dma-ops.c | 68 +++++++++++++++++++++++--------------
1 file changed, 43 insertions(+), 25 deletions(-)
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index 8973fc1e9ccc..f29759d5301f 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -273,22 +273,28 @@ static const struct dma_map_ops xen_grant_dma_ops = {
.dma_supported = xen_grant_dma_supported,
};
-bool xen_is_grant_dma_device(struct device *dev)
+static bool xen_is_dt_grant_dma_device(struct device *dev)
{
struct device_node *iommu_np;
bool has_iommu;
- /* XXX Handle only DT devices for now */
- if (!dev->of_node)
- return false;
-
iommu_np = of_parse_phandle(dev->of_node, "iommus", 0);
- has_iommu = iommu_np && of_device_is_compatible(iommu_np, "xen,grant-dma");
+ has_iommu = iommu_np &&
+ of_device_is_compatible(iommu_np, "xen,grant-dma");
of_node_put(iommu_np);
return has_iommu;
}
+bool xen_is_grant_dma_device(struct device *dev)
+{
+ /* XXX Handle only DT devices for now */
+ if (dev->of_node)
+ return xen_is_dt_grant_dma_device(dev);
+
+ return false;
+}
+
bool xen_virtio_mem_acc(struct virtio_device *dev)
{
if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
@@ -297,45 +303,56 @@ bool xen_virtio_mem_acc(struct virtio_device *dev)
return xen_is_grant_dma_device(dev->dev.parent);
}
-void xen_grant_setup_dma_ops(struct device *dev)
+static int xen_dt_grant_setup_dma_ops(struct device *dev,
+ struct xen_grant_dma_data *data)
{
- struct xen_grant_dma_data *data;
struct of_phandle_args iommu_spec;
- data = find_xen_grant_dma_data(dev);
- if (data) {
- dev_err(dev, "Xen grant DMA data is already created\n");
- return;
- }
-
- /* XXX ACPI device unsupported for now */
- if (!dev->of_node)
- goto err;
-
if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells",
0, &iommu_spec)) {
dev_err(dev, "Cannot parse iommus property\n");
- goto err;
+ return -ESRCH;
}
if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") ||
iommu_spec.args_count != 1) {
dev_err(dev, "Incompatible IOMMU node\n");
of_node_put(iommu_spec.np);
- goto err;
+ return -ESRCH;
}
of_node_put(iommu_spec.np);
+ /*
+ * The endpoint ID here means the ID of the domain where the
+ * corresponding backend is running
+ */
+ data->backend_domid = iommu_spec.args[0];
+
+ return 0;
+}
+
+void xen_grant_setup_dma_ops(struct device *dev)
+{
+ struct xen_grant_dma_data *data;
+
+ data = find_xen_grant_dma_data(dev);
+ if (data) {
+ dev_err(dev, "Xen grant DMA data is already created\n");
+ return;
+ }
+
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
goto err;
- /*
- * The endpoint ID here means the ID of the domain where the corresponding
- * backend is running
- */
- data->backend_domid = iommu_spec.args[0];
+ if (dev->of_node) {
+ if (xen_dt_grant_setup_dma_ops(dev, data))
+ goto err;
+ } else {
+ /* XXX ACPI device unsupported for now */
+ goto err;
+ }
if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data,
GFP_KERNEL))) {
@@ -348,6 +365,7 @@ void xen_grant_setup_dma_ops(struct device *dev)
return;
err:
+ devm_kfree(dev, data);
dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");
}
--
2.35.3
With CONFIG_XEN_VIRTIO_FORCE_GRANT set the default backend domid to 0,
enabling to use xen_grant_dma_ops for those devices.
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/grant-dma-ops.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index f29759d5301f..a00112235877 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -349,6 +349,9 @@ void xen_grant_setup_dma_ops(struct device *dev)
if (dev->of_node) {
if (xen_dt_grant_setup_dma_ops(dev, data))
goto err;
+ } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) {
+ dev_info(dev, "Using dom0 as backend\n");
+ data->backend_domid = 0;
} else {
/* XXX ACPI device unsupported for now */
goto err;
--
2.35.3
Use an x86-specific virtio_check_mem_acc_cb() for Xen in order to setup
the correct DMA ops.
Signed-off-by: Juergen Gross <[email protected]>
---
arch/x86/xen/enlighten_hvm.c | 2 +-
arch/x86/xen/enlighten_pv.c | 2 +-
drivers/xen/grant-dma-ops.c | 10 ++++++++++
include/xen/xen-ops.h | 1 +
4 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 1c1ac418484b..c1cd28e915a3 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -212,7 +212,7 @@ static void __init xen_hvm_guest_init(void)
return;
if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
- virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
+ virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
init_hvm_pv_info();
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 9b1a58dda935..45b24c1b646a 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -112,7 +112,7 @@ static void __init xen_pv_init_platform(void)
{
/* 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);
+ virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index a00112235877..60a7acc334ed 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -372,6 +372,16 @@ void xen_grant_setup_dma_ops(struct device *dev)
dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");
}
+bool xen_virtio_restricted_mem_acc(struct virtio_device *dev)
+{
+ bool ret = xen_virtio_mem_acc(dev);
+
+ if (ret)
+ xen_grant_setup_dma_ops(dev->dev.parent);
+
+ return ret;
+}
+
MODULE_DESCRIPTION("Xen grant DMA-mapping layer");
MODULE_AUTHOR("Juergen Gross <[email protected]>");
MODULE_LICENSE("GPL");
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index dae0f350c678..3dd5aa936f1d 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -219,6 +219,7 @@ static inline void xen_preemptible_hcall_end(void) { }
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);
+bool xen_virtio_restricted_mem_acc(struct virtio_device *dev);
#else
static inline void xen_grant_setup_dma_ops(struct device *dev)
{
--
2.35.3
On 06.10.22 10:15, Juergen Gross wrote:
Hello Juergen
> Use an x86-specific virtio_check_mem_acc_cb() for Xen in order to setup
> the correct DMA ops.
>
> Signed-off-by: Juergen Gross <[email protected]>
> ---
> arch/x86/xen/enlighten_hvm.c | 2 +-
> arch/x86/xen/enlighten_pv.c | 2 +-
> drivers/xen/grant-dma-ops.c | 10 ++++++++++
> include/xen/xen-ops.h | 1 +
> 4 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
> index 1c1ac418484b..c1cd28e915a3 100644
> --- a/arch/x86/xen/enlighten_hvm.c
> +++ b/arch/x86/xen/enlighten_hvm.c
> @@ -212,7 +212,7 @@ static void __init xen_hvm_guest_init(void)
> return;
>
> if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
> - virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
> + virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
>
> init_hvm_pv_info();
>
> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> index 9b1a58dda935..45b24c1b646a 100644
> --- a/arch/x86/xen/enlighten_pv.c
> +++ b/arch/x86/xen/enlighten_pv.c
> @@ -112,7 +112,7 @@ static void __init xen_pv_init_platform(void)
> {
> /* 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);
> + virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
>
> populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
>
> diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
> index a00112235877..60a7acc334ed 100644
> --- a/drivers/xen/grant-dma-ops.c
> +++ b/drivers/xen/grant-dma-ops.c
> @@ -372,6 +372,16 @@ void xen_grant_setup_dma_ops(struct device *dev)
> dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");
> }
>
> +bool xen_virtio_restricted_mem_acc(struct virtio_device *dev)
> +{
> + bool ret = xen_virtio_mem_acc(dev);
The grant usage is mandatory for PV guests, right?
Then xen_virtio_mem_acc() should always return true for PV guests (I
mean even if CONFIG_XEN_VIRTIO_FORCE_GRANT is not set).
> +
> + if (ret)
> + xen_grant_setup_dma_ops(dev->dev.parent);
> +
> + return ret;
> +}
> +
> MODULE_DESCRIPTION("Xen grant DMA-mapping layer");
> MODULE_AUTHOR("Juergen Gross <[email protected]>");
> MODULE_LICENSE("GPL");
> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> index dae0f350c678..3dd5aa936f1d 100644
> --- a/include/xen/xen-ops.h
> +++ b/include/xen/xen-ops.h
> @@ -219,6 +219,7 @@ static inline void xen_preemptible_hcall_end(void) { }
> 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);
> +bool xen_virtio_restricted_mem_acc(struct virtio_device *dev);
> #else
> static inline void xen_grant_setup_dma_ops(struct device *dev)
> {
And probably static inline stub always returning false if
CONFIG_XEN_GRANT_DMA_OPS is not set.
--
Regards,
Oleksandr Tyshchenko
On 06.10.22 10:14, Juergen Gross wrote:
Hello Juergen
> In order to prepare supporting other means than device tree for
> setting up virtio devices under Xen, restructure the functions
> xen_is_grant_dma_device() and xen_grant_setup_dma_ops() a little bit.
>
> Signed-off-by: Juergen Gross <[email protected]>
Patch looks good,
one NIT, xen_dt_grant_setup_dma_ops() down the code doesn't actually
setup DMA OPS, it retrieves the backend domid via device-tree means and
stores it,
so I would rename to it, maybe something like
xen_dt_grant_setup_backend_domid() or xen_dt_grant_init_backend_domid(),
but I am not sure it would be good alternative.
So, w/ or w/o renaming:
Reviewed-by: Oleksandr Tyshchenko <[email protected]>
also
Tested-by: Oleksandr Tyshchenko <[email protected]> # Arm64
only
> ---
> drivers/xen/grant-dma-ops.c | 68 +++++++++++++++++++++++--------------
> 1 file changed, 43 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
> index 8973fc1e9ccc..f29759d5301f 100644
> --- a/drivers/xen/grant-dma-ops.c
> +++ b/drivers/xen/grant-dma-ops.c
> @@ -273,22 +273,28 @@ static const struct dma_map_ops xen_grant_dma_ops = {
> .dma_supported = xen_grant_dma_supported,
> };
>
> -bool xen_is_grant_dma_device(struct device *dev)
> +static bool xen_is_dt_grant_dma_device(struct device *dev)
> {
> struct device_node *iommu_np;
> bool has_iommu;
>
> - /* XXX Handle only DT devices for now */
> - if (!dev->of_node)
> - return false;
> -
> iommu_np = of_parse_phandle(dev->of_node, "iommus", 0);
> - has_iommu = iommu_np && of_device_is_compatible(iommu_np, "xen,grant-dma");
> + has_iommu = iommu_np &&
> + of_device_is_compatible(iommu_np, "xen,grant-dma");
> of_node_put(iommu_np);
>
> return has_iommu;
> }
>
> +bool xen_is_grant_dma_device(struct device *dev)
> +{
> + /* XXX Handle only DT devices for now */
> + if (dev->of_node)
> + return xen_is_dt_grant_dma_device(dev);
> +
> + return false;
> +}
> +
> bool xen_virtio_mem_acc(struct virtio_device *dev)
> {
> if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
> @@ -297,45 +303,56 @@ bool xen_virtio_mem_acc(struct virtio_device *dev)
> return xen_is_grant_dma_device(dev->dev.parent);
> }
>
> -void xen_grant_setup_dma_ops(struct device *dev)
> +static int xen_dt_grant_setup_dma_ops(struct device *dev,
> + struct xen_grant_dma_data *data)
> {
> - struct xen_grant_dma_data *data;
> struct of_phandle_args iommu_spec;
>
> - data = find_xen_grant_dma_data(dev);
> - if (data) {
> - dev_err(dev, "Xen grant DMA data is already created\n");
> - return;
> - }
> -
> - /* XXX ACPI device unsupported for now */
> - if (!dev->of_node)
> - goto err;
> -
> if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells",
> 0, &iommu_spec)) {
> dev_err(dev, "Cannot parse iommus property\n");
> - goto err;
> + return -ESRCH;
> }
>
> if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") ||
> iommu_spec.args_count != 1) {
> dev_err(dev, "Incompatible IOMMU node\n");
> of_node_put(iommu_spec.np);
> - goto err;
> + return -ESRCH;
> }
>
> of_node_put(iommu_spec.np);
>
> + /*
> + * The endpoint ID here means the ID of the domain where the
> + * corresponding backend is running
> + */
> + data->backend_domid = iommu_spec.args[0];
> +
> + return 0;
> +}
> +
> +void xen_grant_setup_dma_ops(struct device *dev)
> +{
> + struct xen_grant_dma_data *data;
> +
> + data = find_xen_grant_dma_data(dev);
> + if (data) {
> + dev_err(dev, "Xen grant DMA data is already created\n");
> + return;
> + }
> +
> data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> if (!data)
> goto err;
>
> - /*
> - * The endpoint ID here means the ID of the domain where the corresponding
> - * backend is running
> - */
> - data->backend_domid = iommu_spec.args[0];
> + if (dev->of_node) {
> + if (xen_dt_grant_setup_dma_ops(dev, data))
> + goto err;
> + } else {
> + /* XXX ACPI device unsupported for now */
> + goto err;
> + }
>
> if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data,
> GFP_KERNEL))) {
> @@ -348,6 +365,7 @@ void xen_grant_setup_dma_ops(struct device *dev)
> return;
>
> err:
> + devm_kfree(dev, data);
> dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");
> }
>
--
Regards,
Oleksandr Tyshchenko
On 06.10.22 10:14, Juergen Gross wrote:
Hello Juergen
> With CONFIG_XEN_VIRTIO_FORCE_GRANT set the default backend domid to 0,
> enabling to use xen_grant_dma_ops for those devices.
>
> Signed-off-by: Juergen Gross <[email protected]>
> ---
> drivers/xen/grant-dma-ops.c | 3 +++
> 1 file changed, 3 insertions(+)
Reviewed-by: Oleksandr Tyshchenko <[email protected]>
>
> diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
> index f29759d5301f..a00112235877 100644
> --- a/drivers/xen/grant-dma-ops.c
> +++ b/drivers/xen/grant-dma-ops.c
> @@ -349,6 +349,9 @@ void xen_grant_setup_dma_ops(struct device *dev)
> if (dev->of_node) {
> if (xen_dt_grant_setup_dma_ops(dev, data))
> goto err;
> + } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) {
> + dev_info(dev, "Using dom0 as backend\n");
> + data->backend_domid = 0;
> } else {
> /* XXX ACPI device unsupported for now */
> goto err;
--
Regards,
Oleksandr Tyshchenko
On Thu, 6 Oct 2022, Oleksandr Tyshchenko wrote:
> On 06.10.22 10:14, Juergen Gross wrote:
>
> Hello Juergen
>
> > With CONFIG_XEN_VIRTIO_FORCE_GRANT set the default backend domid to 0,
> > enabling to use xen_grant_dma_ops for those devices.
> >
> > Signed-off-by: Juergen Gross <[email protected]>
> > ---
> > drivers/xen/grant-dma-ops.c | 3 +++
> > 1 file changed, 3 insertions(+)
>
>
> Reviewed-by: Oleksandr Tyshchenko <[email protected]>
Acked-by: Stefano Stabellini <[email protected]>
> > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
> > index f29759d5301f..a00112235877 100644
> > --- a/drivers/xen/grant-dma-ops.c
> > +++ b/drivers/xen/grant-dma-ops.c
> > @@ -349,6 +349,9 @@ void xen_grant_setup_dma_ops(struct device *dev)
> > if (dev->of_node) {
> > if (xen_dt_grant_setup_dma_ops(dev, data))
> > goto err;
> > + } else if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT)) {
> > + dev_info(dev, "Using dom0 as backend\n");
> > + data->backend_domid = 0;
> > } else {
> > /* XXX ACPI device unsupported for now */
> > goto err;
>
> --
> Regards,
>
> Oleksandr Tyshchenko
>
On Thu, 6 Oct 2022, Oleksandr Tyshchenko wrote:
> On 06.10.22 10:14, Juergen Gross wrote:
>
> Hello Juergen
>
> > In order to prepare supporting other means than device tree for
> > setting up virtio devices under Xen, restructure the functions
> > xen_is_grant_dma_device() and xen_grant_setup_dma_ops() a little bit.
> >
> > Signed-off-by: Juergen Gross <[email protected]>
>
>
> Patch looks good,
>
> one NIT, xen_dt_grant_setup_dma_ops() down the code doesn't actually
> setup DMA OPS, it retrieves the backend domid via device-tree means and
> stores it,
>
> so I would rename to it, maybe something like
> xen_dt_grant_setup_backend_domid() or xen_dt_grant_init_backend_domid(),
> but I am not sure it would be good alternative.
>
>
> So, w/ or w/o renaming:
>
> Reviewed-by: Oleksandr Tyshchenko <[email protected]>
>
> also
>
> Tested-by: Oleksandr Tyshchenko <[email protected]> # Arm64
> only
Acked-by: Stefano Stabellini <[email protected]>
On 06.10.22 18:35, Oleksandr Tyshchenko wrote:
>
> On 06.10.22 10:14, Juergen Gross wrote:
>
> Hello Juergen
>
>> In order to prepare supporting other means than device tree for
>> setting up virtio devices under Xen, restructure the functions
>> xen_is_grant_dma_device() and xen_grant_setup_dma_ops() a little bit.
>>
>> Signed-off-by: Juergen Gross <[email protected]>
>
>
> Patch looks good,
>
> one NIT, xen_dt_grant_setup_dma_ops() down the code doesn't actually
> setup DMA OPS, it retrieves the backend domid via device-tree means and
> stores it,
>
> so I would rename to it, maybe something like
> xen_dt_grant_setup_backend_domid() or xen_dt_grant_init_backend_domid(),
> but I am not sure it would be good alternative.
I'll go with xen_dt_grant_init_backend_domid().
>
>
> So, w/ or w/o renaming:
>
> Reviewed-by: Oleksandr Tyshchenko <[email protected]>
>
> also
>
> Tested-by: Oleksandr Tyshchenko <[email protected]> # Arm64
> only
Thanks,
Juergen
On 06.10.22 18:04, Oleksandr Tyshchenko wrote:
>
> On 06.10.22 10:15, Juergen Gross wrote:
>
>
> Hello Juergen
>
>> Use an x86-specific virtio_check_mem_acc_cb() for Xen in order to setup
>> the correct DMA ops.
>>
>> Signed-off-by: Juergen Gross <[email protected]>
>> ---
>> arch/x86/xen/enlighten_hvm.c | 2 +-
>> arch/x86/xen/enlighten_pv.c | 2 +-
>> drivers/xen/grant-dma-ops.c | 10 ++++++++++
>> include/xen/xen-ops.h | 1 +
>> 4 files changed, 13 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
>> index 1c1ac418484b..c1cd28e915a3 100644
>> --- a/arch/x86/xen/enlighten_hvm.c
>> +++ b/arch/x86/xen/enlighten_hvm.c
>> @@ -212,7 +212,7 @@ static void __init xen_hvm_guest_init(void)
>> return;
>>
>> if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
>> - virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
>> + virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
>>
>> init_hvm_pv_info();
>>
>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
>> index 9b1a58dda935..45b24c1b646a 100644
>> --- a/arch/x86/xen/enlighten_pv.c
>> +++ b/arch/x86/xen/enlighten_pv.c
>> @@ -112,7 +112,7 @@ static void __init xen_pv_init_platform(void)
>> {
>> /* 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);
>> + virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
>>
>> populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
>>
>> diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
>> index a00112235877..60a7acc334ed 100644
>> --- a/drivers/xen/grant-dma-ops.c
>> +++ b/drivers/xen/grant-dma-ops.c
>> @@ -372,6 +372,16 @@ void xen_grant_setup_dma_ops(struct device *dev)
>> dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");
>> }
>>
>> +bool xen_virtio_restricted_mem_acc(struct virtio_device *dev)
>> +{
>> + bool ret = xen_virtio_mem_acc(dev);
>
>
> The grant usage is mandatory for PV guests, right?
>
> Then xen_virtio_mem_acc() should always return true for PV guests (I
> mean even if CONFIG_XEN_VIRTIO_FORCE_GRANT is not set).
Yes.
>
>
>
>> +
>> + if (ret)
>> + xen_grant_setup_dma_ops(dev->dev.parent);
>> +
>> + return ret;
>> +}
>> +
>> MODULE_DESCRIPTION("Xen grant DMA-mapping layer");
>> MODULE_AUTHOR("Juergen Gross <[email protected]>");
>> MODULE_LICENSE("GPL");
>> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
>> index dae0f350c678..3dd5aa936f1d 100644
>> --- a/include/xen/xen-ops.h
>> +++ b/include/xen/xen-ops.h
>> @@ -219,6 +219,7 @@ static inline void xen_preemptible_hcall_end(void) { }
>> 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);
>> +bool xen_virtio_restricted_mem_acc(struct virtio_device *dev);
>> #else
>> static inline void xen_grant_setup_dma_ops(struct device *dev)
>> {
>
>
> And probably static inline stub always returning false if
> CONFIG_XEN_GRANT_DMA_OPS is not set.
Indeed.
Juergen