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Message-ID: <fe337950-f8d0-3d21-a7b1-98b385d71f3e@linux.intel.com>
Date: Wed, 14 Apr 2021 15:00:42 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Keqian Zhu <zhukeqian1@...wei.com>, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
iommu@...ts.linux-foundation.org,
Robin Murphy <robin.murphy@....com>,
Will Deacon <will@...nel.org>, Joerg Roedel <joro@...tes.org>,
Yi Sun <yi.y.sun@...ux.intel.com>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>,
Tian Kevin <kevin.tian@...el.com>
Cc: baolu.lu@...ux.intel.com,
Alex Williamson <alex.williamson@...hat.com>,
Cornelia Huck <cohuck@...hat.com>,
Kirti Wankhede <kwankhede@...dia.com>,
wanghaibin.wang@...wei.com, jiangkunkun@...wei.com,
yuzenghui@...wei.com, lushenming@...wei.com
Subject: Re: [PATCH v3 01/12] iommu: Introduce dirty log tracking framework
Hi Keqian,
On 4/13/21 4:54 PM, Keqian Zhu wrote:
> Some types of IOMMU are capable of tracking DMA dirty log, such as
> ARM SMMU with HTTU or Intel IOMMU with SLADE. This introduces the
> dirty log tracking framework in the IOMMU base layer.
>
> Three new essential interfaces are added, and we maintaince the status
> of dirty log tracking in iommu_domain.
> 1. iommu_switch_dirty_log: Perform actions to start|stop dirty log tracking
> 2. iommu_sync_dirty_log: Sync dirty log from IOMMU into a dirty bitmap
> 3. iommu_clear_dirty_log: Clear dirty log of IOMMU by a mask bitmap
>
> A new dev feature are added to indicate whether a specific type of
> iommu hardware supports and its driver realizes them.
>
> Signed-off-by: Keqian Zhu <zhukeqian1@...wei.com>
> Signed-off-by: Kunkun Jiang <jiangkunkun@...wei.com>
> ---
> drivers/iommu/iommu.c | 150 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/iommu.h | 53 +++++++++++++++
> 2 files changed, 203 insertions(+)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index d0b0a15dba84..667b2d6d2fc0 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1922,6 +1922,7 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
> domain->type = type;
> /* Assume all sizes by default; the driver may override this later */
> domain->pgsize_bitmap = bus->iommu_ops->pgsize_bitmap;
> + mutex_init(&domain->switch_log_lock);
>
> return domain;
> }
> @@ -2720,6 +2721,155 @@ int iommu_domain_set_attr(struct iommu_domain *domain,
> }
> EXPORT_SYMBOL_GPL(iommu_domain_set_attr);
>
> +int iommu_switch_dirty_log(struct iommu_domain *domain, bool enable,
> + unsigned long iova, size_t size, int prot)
> +{
> + const struct iommu_ops *ops = domain->ops;
> + int ret;
> +
> + if (unlikely(!ops || !ops->switch_dirty_log))
> + return -ENODEV;
> +
> + mutex_lock(&domain->switch_log_lock);
> + if (enable && domain->dirty_log_tracking) {
> + ret = -EBUSY;
> + goto out;
> + } else if (!enable && !domain->dirty_log_tracking) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = ops->switch_dirty_log(domain, enable, iova, size, prot);
> + if (ret)
> + goto out;
> +
> + domain->dirty_log_tracking = enable;
> +out:
> + mutex_unlock(&domain->switch_log_lock);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_switch_dirty_log);
Since you also added IOMMU_DEV_FEAT_HWDBM, I am wondering what's the
difference between
iommu_switch_dirty_log(on) vs.
iommu_dev_enable_feature(IOMMU_DEV_FEAT_HWDBM)
iommu_switch_dirty_log(off) vs.
iommu_dev_disable_feature(IOMMU_DEV_FEAT_HWDBM)
> +
> +int iommu_sync_dirty_log(struct iommu_domain *domain, unsigned long iova,
> + size_t size, unsigned long *bitmap,
> + unsigned long base_iova, unsigned long bitmap_pgshift)
> +{
> + const struct iommu_ops *ops = domain->ops;
> + unsigned int min_pagesz;
> + size_t pgsize;
> + int ret = 0;
> +
> + if (unlikely(!ops || !ops->sync_dirty_log))
> + return -ENODEV;
> +
> + min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> + if (!IS_ALIGNED(iova | size, min_pagesz)) {
> + pr_err("unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n",
> + iova, size, min_pagesz);
> + return -EINVAL;
> + }
> +
> + mutex_lock(&domain->switch_log_lock);
> + if (!domain->dirty_log_tracking) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + while (size) {
> + pgsize = iommu_pgsize(domain, iova, size);
> +
> + ret = ops->sync_dirty_log(domain, iova, pgsize,
> + bitmap, base_iova, bitmap_pgshift);
Any reason why do you want to do this in a per-4K page manner? This can
lead to a lot of indirect calls and bad performance.
How about a sync_dirty_pages()?
The same comment applies to other places in this patch series.
> + if (ret)
> + break;
> +
> + pr_debug("dirty_log_sync handle: iova 0x%lx pagesz 0x%zx\n",
> + iova, pgsize);
> +
> + iova += pgsize;
> + size -= pgsize;
> + }
> +out:
> + mutex_unlock(&domain->switch_log_lock);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_sync_dirty_log);
> +
> +static int __iommu_clear_dirty_log(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap,
> + unsigned long base_iova,
> + unsigned long bitmap_pgshift)
> +{
> + const struct iommu_ops *ops = domain->ops;
> + size_t pgsize;
> + int ret = 0;
> +
> + if (unlikely(!ops || !ops->clear_dirty_log))
> + return -ENODEV;
> +
> + while (size) {
> + pgsize = iommu_pgsize(domain, iova, size);
> +
> + ret = ops->clear_dirty_log(domain, iova, pgsize, bitmap,
> + base_iova, bitmap_pgshift);
> + if (ret)
> + break;
> +
> + pr_debug("dirty_log_clear handled: iova 0x%lx pagesz 0x%zx\n",
> + iova, pgsize);
> +
> + iova += pgsize;
> + size -= pgsize;
> + }
> +
> + return ret;
> +}
> +
> +int iommu_clear_dirty_log(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap, unsigned long base_iova,
> + unsigned long bitmap_pgshift)
> +{
> + unsigned long riova, rsize;
> + unsigned int min_pagesz;
> + bool flush = false;
> + int rs, re, start, end;
> + int ret = 0;
> +
> + min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
> + if (!IS_ALIGNED(iova | size, min_pagesz)) {
> + pr_err("unaligned: iova 0x%lx min_pagesz 0x%x\n",
> + iova, min_pagesz);
> + return -EINVAL;
> + }
> +
> + mutex_lock(&domain->switch_log_lock);
> + if (!domain->dirty_log_tracking) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + start = (iova - base_iova) >> bitmap_pgshift;
> + end = start + (size >> bitmap_pgshift);
> + bitmap_for_each_set_region(bitmap, rs, re, start, end) {
> + flush = true;
> + riova = iova + (rs << bitmap_pgshift);
> + rsize = (re - rs) << bitmap_pgshift;
> + ret = __iommu_clear_dirty_log(domain, riova, rsize, bitmap,
> + base_iova, bitmap_pgshift);
> + if (ret)
> + break;
> + }
> +
> + if (flush)
> + iommu_flush_iotlb_all(domain);
> +out:
> + mutex_unlock(&domain->switch_log_lock);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_clear_dirty_log);
> +
> void iommu_get_resv_regions(struct device *dev, struct list_head *list)
> {
> const struct iommu_ops *ops = dev->bus->iommu_ops;
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 5e7fe519430a..7f9ed9f520e2 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -87,6 +87,8 @@ struct iommu_domain {
> void *handler_token;
> struct iommu_domain_geometry geometry;
> void *iova_cookie;
> + bool dirty_log_tracking;
> + struct mutex switch_log_lock;
> };
>
> enum iommu_cap {
> @@ -160,6 +162,7 @@ struct iommu_resv_region {
> enum iommu_dev_features {
> IOMMU_DEV_FEAT_AUX, /* Aux-domain feature */
> IOMMU_DEV_FEAT_SVA, /* Shared Virtual Addresses */
> + IOMMU_DEV_FEAT_HWDBM, /* Hardware Dirty Bit Management */
> };
>
> #define IOMMU_PASID_INVALID (-1U)
> @@ -205,6 +208,9 @@ struct iommu_iotlb_gather {
> * @device_group: find iommu group for a particular device
> * @domain_get_attr: Query domain attributes
> * @domain_set_attr: Change domain attributes
> + * @switch_dirty_log: Perform actions to start|stop dirty log tracking
> + * @sync_dirty_log: Sync dirty log from IOMMU into a dirty bitmap
> + * @clear_dirty_log: Clear dirty log of IOMMU by a mask bitmap
> * @get_resv_regions: Request list of reserved regions for a device
> * @put_resv_regions: Free list of reserved regions for a device
> * @apply_resv_region: Temporary helper call-back for iova reserved ranges
> @@ -260,6 +266,18 @@ struct iommu_ops {
> int (*domain_set_attr)(struct iommu_domain *domain,
> enum iommu_attr attr, void *data);
>
> + /* Track dirty log */
> + int (*switch_dirty_log)(struct iommu_domain *domain, bool enable,
> + unsigned long iova, size_t size, int prot);
> + int (*sync_dirty_log)(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap, unsigned long base_iova,
> + unsigned long bitmap_pgshift);
> + int (*clear_dirty_log)(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap, unsigned long base_iova,
> + unsigned long bitmap_pgshift);
> +
> /* Request/Free a list of reserved regions for a device */
> void (*get_resv_regions)(struct device *dev, struct list_head *list);
> void (*put_resv_regions)(struct device *dev, struct list_head *list);
> @@ -511,6 +529,16 @@ extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
> void *data);
> extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
> void *data);
> +extern int iommu_switch_dirty_log(struct iommu_domain *domain, bool enable,
> + unsigned long iova, size_t size, int prot);
> +extern int iommu_sync_dirty_log(struct iommu_domain *domain, unsigned long iova,
> + size_t size, unsigned long *bitmap,
> + unsigned long base_iova,
> + unsigned long bitmap_pgshift);
> +extern int iommu_clear_dirty_log(struct iommu_domain *domain, unsigned long iova,
> + size_t dma_size, unsigned long *bitmap,
> + unsigned long base_iova,
> + unsigned long bitmap_pgshift);
>
> /* Window handling function prototypes */
> extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
> @@ -901,6 +929,31 @@ static inline int iommu_domain_set_attr(struct iommu_domain *domain,
> return -EINVAL;
> }
>
> +static inline int iommu_switch_dirty_log(struct iommu_domain *domain,
> + bool enable, unsigned long iova,
> + size_t size, int prot)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int iommu_sync_dirty_log(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap,
> + unsigned long base_iova,
> + unsigned long pgshift)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int iommu_clear_dirty_log(struct iommu_domain *domain,
> + unsigned long iova, size_t size,
> + unsigned long *bitmap,
> + unsigned long base_iova,
> + unsigned long pgshift)
> +{
> + return -EINVAL;
> +}
> +
> static inline int iommu_device_register(struct iommu_device *iommu)
> {
> return -ENODEV;
>
Best regards,
baolu
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