Re: [PATCH v2 12/30] s390/pci: get SHM information from list pci

[Pierre Morel]

On 1/14/22 21:31, Matthew Rosato wrote:
> KVM will need information on the special handle mask used to indicate
> emulated devices.  In order to obtain this, a new type of list pci call
> must be made to gather the information.  Extend clp_list_pci_req to
> also fetch the model-dependent-data field that holds this mask.
>
> Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> ---
>   arch/s390/include/asm/pci.h     |  1 +
>   arch/s390/include/asm/pci_clp.h |  2 +-
>   arch/s390/pci/pci_clp.c         | 28 +++++++++++++++++++++++++---
>   3 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 00a2c24d6d2b..f3cd2da8128c 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -227,6 +227,7 @@ int clp_enable_fh(struct zpci_dev *zdev, u32 *fh, u8 nr_dma_as);
>   int clp_disable_fh(struct zpci_dev *zdev, u32 *fh);
>   int clp_get_state(u32 fid, enum zpci_state *state);
>   int clp_refresh_fh(u32 fid, u32 *fh);
> +int zpci_get_mdd(u32 *mdd);
>   
>   /* UID */
>   void update_uid_checking(bool new);
> diff --git a/arch/s390/include/asm/pci_clp.h b/arch/s390/include/asm/pci_clp.h
> index 124fadfb74b9..d6bc324763f3 100644
> --- a/arch/s390/include/asm/pci_clp.h
> +++ b/arch/s390/include/asm/pci_clp.h
> @@ -76,7 +76,7 @@ struct clp_req_list_pci {
>   struct clp_rsp_list_pci {
>   	struct clp_rsp_hdr hdr;
>   	u64 resume_token;
> -	u32 reserved2;
> +	u32 mdd;
>   	u16 max_fn;
>   	u8			: 7;
>   	u8 uid_checking		: 1;
> diff --git a/arch/s390/pci/pci_clp.c b/arch/s390/pci/pci_clp.c
> index bc7446566cbc..308ffb93413f 100644
> --- a/arch/s390/pci/pci_clp.c
> +++ b/arch/s390/pci/pci_clp.c
> @@ -328,7 +328,7 @@ int clp_disable_fh(struct zpci_dev *zdev, u32 *fh)
>   }
>   
>   static int clp_list_pci_req(struct clp_req_rsp_list_pci *rrb,
> -			    u64 *resume_token, int *nentries)
> +			    u64 *resume_token, int *nentries, u32 *mdd)
>   {
>   	int rc;
>   
> @@ -354,6 +354,8 @@ static int clp_list_pci_req(struct clp_req_rsp_list_pci *rrb,
>   	*nentries = (rrb->response.hdr.len - LIST_PCI_HDR_LEN) /
>   		rrb->response.entry_size;
>   	*resume_token = rrb->response.resume_token;
> +	if (mdd)
> +		*mdd = rrb->response.mdd;
>   
>   	return rc;
>   }
> @@ -365,7 +367,7 @@ static int clp_list_pci(struct clp_req_rsp_list_pci *rrb, void *data,
>   	int nentries, i, rc;
>   
>   	do {
> -		rc = clp_list_pci_req(rrb, &resume_token, &nentries);
> +		rc = clp_list_pci_req(rrb, &resume_token, &nentries, NULL);
>   		if (rc)
>   			return rc;
>   		for (i = 0; i < nentries; i++)
> @@ -383,7 +385,7 @@ static int clp_find_pci(struct clp_req_rsp_list_pci *rrb, u32 fid,
>   	int nentries, i, rc;
>   
>   	do {
> -		rc = clp_list_pci_req(rrb, &resume_token, &nentries);
> +		rc = clp_list_pci_req(rrb, &resume_token, &nentries, NULL);
>   		if (rc)
>   			return rc;
>   		fh_list = rrb->response.fh_list;
> @@ -468,6 +470,26 @@ int clp_get_state(u32 fid, enum zpci_state *state)
>   	return rc;
>   }
>   
> +int zpci_get_mdd(u32 *mdd)
> +{
> +	struct clp_req_rsp_list_pci *rrb;
> +	u64 resume_token = 0;
> +	int nentries, rc;
> +
> +	if (!mdd)
> +		return -EINVAL;

I think this tests is not useful.
The caller must take care not to call with a NULL pointer,
what the only caller today make sure.


> +
> +	rrb = clp_alloc_block(GFP_KERNEL);
> +	if (!rrb)
> +		return -ENOMEM;
> +
> +	rc = clp_list_pci_req(rrb, &resume_token, &nentries, mdd);
> +
> +	clp_free_block(rrb);
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(zpci_get_mdd);
> +
>   static int clp_base_slpc(struct clp_req *req, struct clp_req_rsp_slpc *lpcb)
>   {
>   	unsigned long limit = PAGE_SIZE - sizeof(lpcb->request);

--
Pierre Morel
IBM Lab Boeblingen