diff mbox series

[for-next,v1,1/2] RDMA/rxe: Enable ODP in RDMA FLUSH operation

Message ID 20250314081056.3496708-2-matsuda-daisuke@fujitsu.com (mailing list archive)
State Superseded
Headers show
Series RDMA/rxe: RDMA FLUSH and ATOMIC WRITE with ODP | expand

Commit Message

Daisuke Matsuda (Fujitsu) March 14, 2025, 8:10 a.m. UTC 
For persistent memories, add rxe_odp_flush_pmem_iova() so that ODP specific
steps are executed. Otherwise, no additional consideration is required.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
---
 drivers/infiniband/sw/rxe/rxe.c      |  1 +
 drivers/infiniband/sw/rxe/rxe_loc.h  |  7 +++
 drivers/infiniband/sw/rxe/rxe_odp.c  | 73 ++++++++++++++++++++++++++--
 drivers/infiniband/sw/rxe/rxe_resp.c | 13 ++---
 include/rdma/ib_verbs.h              |  1 +
 5 files changed, 85 insertions(+), 10 deletions(-)

Comments

Zhu Yanjun March 15, 2025, 7:23 p.m. UTC | #1 
在 2025/3/14 9:10, Daisuke Matsuda 写道:
> For persistent memories, add rxe_odp_flush_pmem_iova() so that ODP specific
> steps are executed. Otherwise, no additional consideration is required.

Thanks a lot. It is better if the perftest results are also attached.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Zhu Yanjun

> 
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> ---
>   drivers/infiniband/sw/rxe/rxe.c      |  1 +
>   drivers/infiniband/sw/rxe/rxe_loc.h  |  7 +++
>   drivers/infiniband/sw/rxe/rxe_odp.c  | 73 ++++++++++++++++++++++++++--
>   drivers/infiniband/sw/rxe/rxe_resp.c | 13 ++---
>   include/rdma/ib_verbs.h              |  1 +
>   5 files changed, 85 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
> index 4e56a371deb5..df66f8f9efa1 100644
> --- a/drivers/infiniband/sw/rxe/rxe.c
> +++ b/drivers/infiniband/sw/rxe/rxe.c
> @@ -109,6 +109,7 @@ static void rxe_init_device_param(struct rxe_dev *rxe)
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_READ;
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_ATOMIC;
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
> +		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_FLUSH;
>   	}
>   }
>   
> diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
> index feb386d98d1d..0012bebe96ef 100644
> --- a/drivers/infiniband/sw/rxe/rxe_loc.h
> +++ b/drivers/infiniband/sw/rxe/rxe_loc.h
> @@ -194,6 +194,8 @@ int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
>   		    enum rxe_mr_copy_dir dir);
>   int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>   			 u64 compare, u64 swap_add, u64 *orig_val);
> +int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
> +			    unsigned int length);
>   #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>   static inline int
>   rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
> @@ -212,6 +214,11 @@ rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>   {
>   	return RESPST_ERR_UNSUPPORTED_OPCODE;
>   }
> +static inline int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
> +					  unsigned int length)
> +{
> +	return -EOPNOTSUPP;
> +}
>   #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>   
>   #endif /* RXE_LOC_H */
> diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
> index 94f7bbe14981..c1671e5efd70 100644
> --- a/drivers/infiniband/sw/rxe/rxe_odp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
> @@ -4,6 +4,7 @@
>    */
>   
>   #include <linux/hmm.h>
> +#include <linux/libnvdimm.h>
>   
>   #include <rdma/ib_umem_odp.h>
>   
> @@ -147,6 +148,16 @@ static inline bool rxe_check_pagefault(struct ib_umem_odp *umem_odp,
>   	return need_fault;
>   }
>   
> +static unsigned long rxe_odp_iova_to_index(struct ib_umem_odp *umem_odp, u64 iova)
> +{
> +	return (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> +}
> +
> +static unsigned long rxe_odp_iova_to_page_offset(struct ib_umem_odp *umem_odp, u64 iova)
> +{
> +	return iova & (BIT(umem_odp->page_shift) - 1);
> +}
> +
>   static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
>   {
>   	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> @@ -190,8 +201,8 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
>   	size_t offset;
>   	u8 *user_va;
>   
> -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> -	offset = iova & (BIT(umem_odp->page_shift) - 1);
> +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> +	offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
>   
>   	while (length > 0) {
>   		u8 *src, *dest;
> @@ -277,8 +288,8 @@ static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>   		return RESPST_ERR_RKEY_VIOLATION;
>   	}
>   
> -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> -	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
> +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> +	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
>   	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
>   	if (!page)
>   		return RESPST_ERR_RKEY_VIOLATION;
> @@ -324,3 +335,57 @@ int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>   
>   	return err;
>   }
> +
> +int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
> +			    unsigned int length)
> +{
> +	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> +	unsigned int page_offset;
> +	unsigned long index;
> +	struct page *page;
> +	unsigned int bytes;
> +	int err;
> +	u8 *va;
> +
> +	/* mr must be valid even if length is zero */
> +	if (WARN_ON(!mr))
> +		return -EINVAL;
> +
> +	if (length == 0)
> +		return 0;
> +
> +	err = mr_check_range(mr, iova, length);
> +	if (err)
> +		return err;
> +
> +	err = rxe_odp_map_range_and_lock(mr, iova, length,
> +					 RXE_PAGEFAULT_DEFAULT);
> +	if (err)
> +		return err;
> +
> +	while (length > 0) {
> +		index = rxe_odp_iova_to_index(umem_odp, iova);
> +		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> +
> +		page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
> +		if (!page) {
> +			mutex_unlock(&umem_odp->umem_mutex);
> +			return -EFAULT;
> +		}
> +
> +		bytes = min_t(unsigned int, length,
> +			      mr_page_size(mr) - page_offset);
> +
> +		va = kmap_local_page(page);
> +		arch_wb_cache_pmem(va + page_offset, bytes);
> +		kunmap_local(va);
> +
> +		length -= bytes;
> +		iova += bytes;
> +		page_offset = 0;
> +	}
> +
> +	mutex_unlock(&umem_odp->umem_mutex);
> +
> +	return 0;
> +}
> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> index 54ba9ee1acc5..dd65a8872111 100644
> --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> @@ -649,10 +649,6 @@ static enum resp_states process_flush(struct rxe_qp *qp,
>   	struct rxe_mr *mr = qp->resp.mr;
>   	struct resp_res *res = qp->resp.res;
>   
> -	/* ODP is not supported right now. WIP. */
> -	if (mr->umem->is_odp)
> -		return RESPST_ERR_UNSUPPORTED_OPCODE;
> -
>   	/* oA19-14, oA19-15 */
>   	if (res && res->replay)
>   		return RESPST_ACKNOWLEDGE;
> @@ -670,8 +666,13 @@ static enum resp_states process_flush(struct rxe_qp *qp,
>   	}
>   
>   	if (res->flush.type & IB_FLUSH_PERSISTENT) {
> -		if (rxe_flush_pmem_iova(mr, start, length))
> -			return RESPST_ERR_RKEY_VIOLATION;
> +		if (mr->umem->is_odp) {
> +			if (rxe_odp_flush_pmem_iova(mr, start, length))
> +				return RESPST_ERR_RKEY_VIOLATION;
> +		} else {
> +			if (rxe_flush_pmem_iova(mr, start, length))
> +				return RESPST_ERR_RKEY_VIOLATION;
> +		}
>   		/* Make data persistent. */
>   		wmb();
>   	} else if (res->flush.type & IB_FLUSH_GLOBAL) {
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index 9941f4185c79..da07d3e2db1d 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -325,6 +325,7 @@ enum ib_odp_transport_cap_bits {
>   	IB_ODP_SUPPORT_READ	= 1 << 3,
>   	IB_ODP_SUPPORT_ATOMIC	= 1 << 4,
>   	IB_ODP_SUPPORT_SRQ_RECV	= 1 << 5,
> +	IB_ODP_SUPPORT_FLUSH	= 1 << 6,
>   };
>   
>   struct ib_odp_caps {
Leon Romanovsky March 17, 2025, 6:22 p.m. UTC | #2 
On Fri, Mar 14, 2025 at 05:10:55PM +0900, Daisuke Matsuda wrote:
> For persistent memories, add rxe_odp_flush_pmem_iova() so that ODP specific
> steps are executed. Otherwise, no additional consideration is required.
> 
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> ---
>  drivers/infiniband/sw/rxe/rxe.c      |  1 +
>  drivers/infiniband/sw/rxe/rxe_loc.h  |  7 +++
>  drivers/infiniband/sw/rxe/rxe_odp.c  | 73 ++++++++++++++++++++++++++--
>  drivers/infiniband/sw/rxe/rxe_resp.c | 13 ++---
>  include/rdma/ib_verbs.h              |  1 +
>  5 files changed, 85 insertions(+), 10 deletions(-)

<...>

>  
> +static unsigned long rxe_odp_iova_to_index(struct ib_umem_odp *umem_odp, u64 iova)
> +{
> +	return (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> +}
> +
> +static unsigned long rxe_odp_iova_to_page_offset(struct ib_umem_odp *umem_odp, u64 iova)
> +{
> +	return iova & (BIT(umem_odp->page_shift) - 1);
> +}
> +
>  static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
>  {
>  	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> @@ -190,8 +201,8 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
>  	size_t offset;
>  	u8 *user_va;
>  
> -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> -	offset = iova & (BIT(umem_odp->page_shift) - 1);
> +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> +	offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
>  
>  	while (length > 0) {
>  		u8 *src, *dest;
> @@ -277,8 +288,8 @@ static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>  		return RESPST_ERR_RKEY_VIOLATION;
>  	}
>  
> -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> -	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
> +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> +	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
>  	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
>  	if (!page)
>  		return RESPST_ERR_RKEY_VIOLATION;
> @@ -324,3 +335,57 @@ int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>  
>  	return err;
>  }
> +
> +int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
> +			    unsigned int length)
> +{

This function looks almost similar to existing rxe_flush_pmem_iova().
Can't you reuse existing functions instead of duplicating?

Thanks

> +	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> +	unsigned int page_offset;
> +	unsigned long index;
> +	struct page *page;
> +	unsigned int bytes;
> +	int err;
> +	u8 *va;
> +
> +	/* mr must be valid even if length is zero */
> +	if (WARN_ON(!mr))
> +		return -EINVAL;
> +
> +	if (length == 0)
> +		return 0;
> +
> +	err = mr_check_range(mr, iova, length);
> +	if (err)
> +		return err;
> +
> +	err = rxe_odp_map_range_and_lock(mr, iova, length,
> +					 RXE_PAGEFAULT_DEFAULT);
> +	if (err)
> +		return err;
> +
> +	while (length > 0) {
> +		index = rxe_odp_iova_to_index(umem_odp, iova);
> +		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> +
> +		page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
> +		if (!page) {
> +			mutex_unlock(&umem_odp->umem_mutex);
> +			return -EFAULT;
> +		}
> +
> +		bytes = min_t(unsigned int, length,
> +			      mr_page_size(mr) - page_offset);
> +
> +		va = kmap_local_page(page);
> +		arch_wb_cache_pmem(va + page_offset, bytes);
> +		kunmap_local(va);
> +
> +		length -= bytes;
> +		iova += bytes;
> +		page_offset = 0;
> +	}
> +
> +	mutex_unlock(&umem_odp->umem_mutex);
> +
> +	return 0;
> +}
Daisuke Matsuda (Fujitsu) March 18, 2025, 9:47 a.m. UTC | #3 
On Tue, Mar 18, 2025 3:23 AM Leon Romanovsky wrote:
> On Fri, Mar 14, 2025 at 05:10:55PM +0900, Daisuke Matsuda wrote:
> > For persistent memories, add rxe_odp_flush_pmem_iova() so that ODP specific
> > steps are executed. Otherwise, no additional consideration is required.
> >
> > Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
> > ---
> >  drivers/infiniband/sw/rxe/rxe.c      |  1 +
> >  drivers/infiniband/sw/rxe/rxe_loc.h  |  7 +++
> >  drivers/infiniband/sw/rxe/rxe_odp.c  | 73 ++++++++++++++++++++++++++--
> >  drivers/infiniband/sw/rxe/rxe_resp.c | 13 ++---
> >  include/rdma/ib_verbs.h              |  1 +
> >  5 files changed, 85 insertions(+), 10 deletions(-)
> 
> <...>
> 
> >
> > +static unsigned long rxe_odp_iova_to_index(struct ib_umem_odp *umem_odp, u64 iova)
> > +{
> > +	return (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> > +}
> > +
> > +static unsigned long rxe_odp_iova_to_page_offset(struct ib_umem_odp *umem_odp, u64 iova)
> > +{
> > +	return iova & (BIT(umem_odp->page_shift) - 1);
> > +}
> > +
> >  static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
> >  {
> >  	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> > @@ -190,8 +201,8 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
> >  	size_t offset;
> >  	u8 *user_va;
> >
> > -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> > -	offset = iova & (BIT(umem_odp->page_shift) - 1);
> > +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> > +	offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> >
> >  	while (length > 0) {
> >  		u8 *src, *dest;
> > @@ -277,8 +288,8 @@ static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
> >  		return RESPST_ERR_RKEY_VIOLATION;
> >  	}
> >
> > -	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
> > -	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
> > +	idx = rxe_odp_iova_to_index(umem_odp, iova);
> > +	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> >  	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
> >  	if (!page)
> >  		return RESPST_ERR_RKEY_VIOLATION;
> > @@ -324,3 +335,57 @@ int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
> >
> >  	return err;
> >  }
> > +
> > +int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
> > +			    unsigned int length)
> > +{
> 
> This function looks almost similar to existing rxe_flush_pmem_iova().
> Can't you reuse existing functions instead of duplicating?

Hi,
Thank you for the review.

I will send new patches to let these functions share the common elements,
but the while loops must stay separated. They use different page fetching logic,
and it is not feasible to unite the functions.

Thanks,
Daisuke

> 
> Thanks
> 
> > +	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> > +	unsigned int page_offset;
> > +	unsigned long index;
> > +	struct page *page;
> > +	unsigned int bytes;
> > +	int err;
> > +	u8 *va;
> > +
> > +	/* mr must be valid even if length is zero */
> > +	if (WARN_ON(!mr))
> > +		return -EINVAL;
> > +
> > +	if (length == 0)
> > +		return 0;
> > +
> > +	err = mr_check_range(mr, iova, length);
> > +	if (err)
> > +		return err;
> > +
> > +	err = rxe_odp_map_range_and_lock(mr, iova, length,
> > +					 RXE_PAGEFAULT_DEFAULT);
> > +	if (err)
> > +		return err;
> > +
> > +	while (length > 0) {
> > +		index = rxe_odp_iova_to_index(umem_odp, iova);
> > +		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> > +
> > +		page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
> > +		if (!page) {
> > +			mutex_unlock(&umem_odp->umem_mutex);
> > +			return -EFAULT;
> > +		}
> > +
> > +		bytes = min_t(unsigned int, length,
> > +			      mr_page_size(mr) - page_offset);
> > +
> > +		va = kmap_local_page(page);
> > +		arch_wb_cache_pmem(va + page_offset, bytes);
> > +		kunmap_local(va);
> > +
> > +		length -= bytes;
> > +		iova += bytes;
> > +		page_offset = 0;
> > +	}
> > +
> > +	mutex_unlock(&umem_odp->umem_mutex);
> > +
> > +	return 0;
> > +}
diff mbox series

Patch

diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
index 4e56a371deb5..df66f8f9efa1 100644
--- a/drivers/infiniband/sw/rxe/rxe.c
+++ b/drivers/infiniband/sw/rxe/rxe.c
@@ -109,6 +109,7 @@  static void rxe_init_device_param(struct rxe_dev *rxe)
 		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_READ;
 		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_ATOMIC;
 		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
+		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_FLUSH;
 	}
 }
 
diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index feb386d98d1d..0012bebe96ef 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -194,6 +194,8 @@  int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 		    enum rxe_mr_copy_dir dir);
 int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 			 u64 compare, u64 swap_add, u64 *orig_val);
+int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
+			    unsigned int length);
 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 static inline int
 rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
@@ -212,6 +214,11 @@  rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 {
 	return RESPST_ERR_UNSUPPORTED_OPCODE;
 }
+static inline int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
+					  unsigned int length)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 
 #endif /* RXE_LOC_H */
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
index 94f7bbe14981..c1671e5efd70 100644
--- a/drivers/infiniband/sw/rxe/rxe_odp.c
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -4,6 +4,7 @@ 
  */
 
 #include <linux/hmm.h>
+#include <linux/libnvdimm.h>
 
 #include <rdma/ib_umem_odp.h>
 
@@ -147,6 +148,16 @@  static inline bool rxe_check_pagefault(struct ib_umem_odp *umem_odp,
 	return need_fault;
 }
 
+static unsigned long rxe_odp_iova_to_index(struct ib_umem_odp *umem_odp, u64 iova)
+{
+	return (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+}
+
+static unsigned long rxe_odp_iova_to_page_offset(struct ib_umem_odp *umem_odp, u64 iova)
+{
+	return iova & (BIT(umem_odp->page_shift) - 1);
+}
+
 static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
 {
 	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
@@ -190,8 +201,8 @@  static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
 	size_t offset;
 	u8 *user_va;
 
-	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
-	offset = iova & (BIT(umem_odp->page_shift) - 1);
+	idx = rxe_odp_iova_to_index(umem_odp, iova);
+	offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
 
 	while (length > 0) {
 		u8 *src, *dest;
@@ -277,8 +288,8 @@  static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 		return RESPST_ERR_RKEY_VIOLATION;
 	}
 
-	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
-	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
+	idx = rxe_odp_iova_to_index(umem_odp, iova);
+	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
 	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
 	if (!page)
 		return RESPST_ERR_RKEY_VIOLATION;
@@ -324,3 +335,57 @@  int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 
 	return err;
 }
+
+int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
+			    unsigned int length)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	unsigned int page_offset;
+	unsigned long index;
+	struct page *page;
+	unsigned int bytes;
+	int err;
+	u8 *va;
+
+	/* mr must be valid even if length is zero */
+	if (WARN_ON(!mr))
+		return -EINVAL;
+
+	if (length == 0)
+		return 0;
+
+	err = mr_check_range(mr, iova, length);
+	if (err)
+		return err;
+
+	err = rxe_odp_map_range_and_lock(mr, iova, length,
+					 RXE_PAGEFAULT_DEFAULT);
+	if (err)
+		return err;
+
+	while (length > 0) {
+		index = rxe_odp_iova_to_index(umem_odp, iova);
+		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
+
+		page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
+		if (!page) {
+			mutex_unlock(&umem_odp->umem_mutex);
+			return -EFAULT;
+		}
+
+		bytes = min_t(unsigned int, length,
+			      mr_page_size(mr) - page_offset);
+
+		va = kmap_local_page(page);
+		arch_wb_cache_pmem(va + page_offset, bytes);
+		kunmap_local(va);
+
+		length -= bytes;
+		iova += bytes;
+		page_offset = 0;
+	}
+
+	mutex_unlock(&umem_odp->umem_mutex);
+
+	return 0;
+}
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 54ba9ee1acc5..dd65a8872111 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -649,10 +649,6 @@  static enum resp_states process_flush(struct rxe_qp *qp,
 	struct rxe_mr *mr = qp->resp.mr;
 	struct resp_res *res = qp->resp.res;
 
-	/* ODP is not supported right now. WIP. */
-	if (mr->umem->is_odp)
-		return RESPST_ERR_UNSUPPORTED_OPCODE;
-
 	/* oA19-14, oA19-15 */
 	if (res && res->replay)
 		return RESPST_ACKNOWLEDGE;
@@ -670,8 +666,13 @@  static enum resp_states process_flush(struct rxe_qp *qp,
 	}
 
 	if (res->flush.type & IB_FLUSH_PERSISTENT) {
-		if (rxe_flush_pmem_iova(mr, start, length))
-			return RESPST_ERR_RKEY_VIOLATION;
+		if (mr->umem->is_odp) {
+			if (rxe_odp_flush_pmem_iova(mr, start, length))
+				return RESPST_ERR_RKEY_VIOLATION;
+		} else {
+			if (rxe_flush_pmem_iova(mr, start, length))
+				return RESPST_ERR_RKEY_VIOLATION;
+		}
 		/* Make data persistent. */
 		wmb();
 	} else if (res->flush.type & IB_FLUSH_GLOBAL) {
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9941f4185c79..da07d3e2db1d 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -325,6 +325,7 @@  enum ib_odp_transport_cap_bits {
 	IB_ODP_SUPPORT_READ	= 1 << 3,
 	IB_ODP_SUPPORT_ATOMIC	= 1 << 4,
 	IB_ODP_SUPPORT_SRQ_RECV	= 1 << 5,
+	IB_ODP_SUPPORT_FLUSH	= 1 << 6,
 };
 
 struct ib_odp_caps {