Re: [PATCH v6 12/13] xen/arm: Suspend/resume IOMMU on Xen suspend/resume

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

On 02.09.25 01:10, Mykola Kvach wrote:

Hello Mykola

> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>
> This is done using generic iommu_suspend/resume functions that cause
> IOMMU driver specific suspend/resume handlers to be called for enabled
> IOMMU (if one has suspend/resume driver handlers implemented).
>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
> Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> ---
> Changes in V6:
> - Drop iommu_enabled check from host system suspend.
I do not have any comments for the updated version, thanks.


> ---
>   xen/arch/arm/suspend.c                | 11 +++++++++++
>   xen/drivers/passthrough/arm/smmu-v3.c | 10 ++++++++++
>   xen/drivers/passthrough/arm/smmu.c    | 10 ++++++++++
>   3 files changed, 31 insertions(+)
>
> diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
> index 35b20581f1..f3a3b831c5 100644
> --- a/xen/arch/arm/suspend.c
> +++ b/xen/arch/arm/suspend.c
> @@ -5,6 +5,7 @@
>   
>   #include <xen/console.h>
>   #include <xen/cpu.h>
> +#include <xen/iommu.h>
>   #include <xen/llc-coloring.h>
>   #include <xen/sched.h>
>   #include <xen/tasklet.h>
> @@ -62,6 +63,13 @@ static void cf_check system_suspend(void *data)
>   
>       time_suspend();
>   
> +    status = iommu_suspend();
> +    if ( status )
> +    {
> +        system_state = SYS_STATE_resume;
> +        goto resume_time;
> +    }
> +
>       console_start_sync();
>       status = console_suspend();
>       if ( status )
> @@ -118,6 +126,9 @@ static void cf_check system_suspend(void *data)
>       console_resume();
>       console_end_sync();
>   
> +    iommu_resume();
> +
> + resume_time:
>       time_resume();
>   
>    resume_nonboot_cpus:
> diff --git a/xen/drivers/passthrough/arm/smmu-v3.c 
> b/xen/drivers/passthrough/arm/smmu-v3.c
> index 81071f4018..f887faf7dc 100644
> --- a/xen/drivers/passthrough/arm/smmu-v3.c
> +++ b/xen/drivers/passthrough/arm/smmu-v3.c
> @@ -2854,6 +2854,13 @@ static void arm_smmu_iommu_xen_domain_teardown(struct 
> domain *d)
>         xfree(xen_domain);
>   }
>   
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +static int arm_smmu_suspend(void)
> +{
> +       return -ENOSYS;
> +}
> +#endif
> +
>   static const struct iommu_ops arm_smmu_iommu_ops = {
>         .page_sizes             = PAGE_SIZE_4K,
>         .init                   = arm_smmu_iommu_xen_domain_init,
> @@ -2866,6 +2873,9 @@ static const struct iommu_ops arm_smmu_iommu_ops = {
>         .unmap_page             = arm_iommu_unmap_page,
>         .dt_xlate               = arm_smmu_dt_xlate,
>         .add_device             = arm_smmu_add_device,
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +       .suspend                = arm_smmu_suspend,
> +#endif
>   };
>   
>   static __init int arm_smmu_dt_init(struct dt_device_node *dev,
> diff --git a/xen/drivers/passthrough/arm/smmu.c 
> b/xen/drivers/passthrough/arm/smmu.c
> index 22d306d0cb..45f29ef8ec 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -2947,6 +2947,13 @@ static void arm_smmu_iommu_domain_teardown(struct domain 
> *d)
>         xfree(xen_domain);
>   }
>   
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +static int arm_smmu_suspend(void)
> +{
> +       return -ENOSYS;
> +}
> +#endif
> +
>   static const struct iommu_ops arm_smmu_iommu_ops = {
>       .page_sizes = PAGE_SIZE_4K,
>       .init = arm_smmu_iommu_domain_init,
> @@ -2960,6 +2967,9 @@ static const struct iommu_ops arm_smmu_iommu_ops = {
>       .map_page = arm_iommu_map_page,
>       .unmap_page = arm_iommu_unmap_page,
>       .dt_xlate = arm_smmu_dt_xlate_generic,
> +#ifdef CONFIG_SYSTEM_SUSPEND
> +    .suspend = arm_smmu_suspend,
> +#endif
>   };
>   
>   static struct arm_smmu_device *find_smmu(const struct device *dev)