Re: [PATCH 12/32] s390/pci: get SHM information from list pci

Niklas Schnelle
2021-12-08T12:21:46Z

On Tue, 2021-12-07 at 15:57 -0500, 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. Remove the unused data pointer
> from clp_list_pci and __clp_add and instead optionally pass a pointer to
> a model-dependent-data field. Additionally, allow for clp_list_pci calls
> that don't specify a callback - in this case, just do the first pass of
> list pci and exit.
>
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> ---
> arch/s390/include/asm/pci.h | 6 ++++++
> arch/s390/include/asm/pci_clp.h | 2 +-
> arch/s390/pci/pci.c | 19 +++++++++++++++++++
> arch/s390/pci/pci_clp.c | 16 ++++++++++------
> 4 files changed, 36 insertions(+), 7 deletions(-)
>
> diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
> index 00a2c24d6d2b..86f43644756d 100644
> --- a/arch/s390/include/asm/pci.h
> +++ b/arch/s390/include/asm/pci.h
> @@ -219,12 +219,18 @@ int zpci_unregister_ioat(struct zpci_dev *, u8);
> void zpci_remove_reserved_devices(void);
> void zpci_update_fh(struct zpci_dev *zdev, u32 fh);
>
---8<---
> -static int clp_list_pci(struct clp_req_rsp_list_pci *rrb, void *data,
> - void (*cb)(struct clp_fh_list_entry *, void *))
> +int clp_list_pci(struct clp_req_rsp_list_pci *rrb, u32 *mdd,
> + void (*cb)(struct clp_fh_list_entry *))
> {
> u64 resume_token = 0;
> int nentries, i, rc;
> @@ -368,8 +368,12 @@ static int clp_list_pci(struct clp_req_rsp_list_pci *rrb, void *data,
> rc = clp_list_pci_req(rrb, &resume_token, &nentries);
> if (rc)
> return rc;
> + if (mdd)
> + *mdd = rrb->response.mdd;
> + if (!cb)
> + return 0;

I think it would be slightly cleaner to instead de-static
clp_list_pci_req() and call that directly. Just because that makes the
clp_list_pci() still list all PCI functions and allows us to get rid of
the data parameter completely.

Also, I've been thinking about moving clp_scan_devices(),
clp_get_state(), and clp_refresh_fh() out of pci_clp.c because they are
higher level. I think that would nicely fit your zpci_get_mdd() in
pci.c with or without the above suggestion. Then we could do the
removal of the unused data parameter in that series as a cleanup. What
do you think?

> for (i = 0; i < nentries; i++)
> - cb(&rrb->response.fh_list[i], data);
> + cb(&rrb->response.fh_list[i]);
> } while (resume_token);
>
> return rc;
> @@ -398,7 +402,7 @@ static int clp_find_pci(struct clp_req_rsp_list_pci *rrb, u32 fid,
> return -ENODEV;
> }
>
> -static void __clp_add(struct clp_fh_list_entry *entry, void *data)
> +static void __clp_add(struct clp_fh_list_entry *entry)
> {
> struct zpci_dev *zdev;
>