Re: [PATCH v6 04/17] powerpc/vas: Add platform specific user window operations

[Nicholas Piggin]

Excerpts from Haren Myneni's message of June 18, 2021 6:31 am:
> 
> PowerNV uses registers to open/close VAS windows, and getting the
> paste address. Whereas the hypervisor calls are used on PowerVM.
> 
> This patch adds the platform specific user space window operations
> and register with the common VAS user space interface.
> 
> Signed-off-by: Haren Myneni 
> Reviewed-by: Nicholas Piggin 
> ---
>  arch/powerpc/include/asm/vas.h  | 16 +--
>  arch/powerpc/platforms/book3s/vas-api.c | 53 +
>  arch/powerpc/platforms/powernv/vas-window.c | 45 -
>  arch/powerpc/platforms/powernv/vas.h|  2 +
>  4 files changed, 91 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
> index 6076adf9ab4f..163a8bb85d02 100644
> --- a/arch/powerpc/include/asm/vas.h
> +++ b/arch/powerpc/include/asm/vas.h
> @@ -5,6 +5,7 @@
>  
>  #ifndef _ASM_POWERPC_VAS_H
>  #define _ASM_POWERPC_VAS_H
> +#include 
>  
>  struct vas_window;
>  
> @@ -48,6 +49,16 @@ enum vas_cop_type {
>   VAS_COP_TYPE_MAX,
>  };
>  
> +/*
> + * User space window operations used for powernv and powerVM
> + */
> +struct vas_user_win_ops {
> + struct vas_window * (*open_win)(int vas_id, u64 flags,
> + enum vas_cop_type);

Thanks for changing that to not pass down the struct passed in by the 
user. Looks good.

Thanks,
Nick

[PATCH v6 04/17] powerpc/vas: Add platform specific user window operations

[Haren Myneni]

PowerNV uses registers to open/close VAS windows, and getting the
paste address. Whereas the hypervisor calls are used on PowerVM.

This patch adds the platform specific user space window operations
and register with the common VAS user space interface.

Signed-off-by: Haren Myneni 
Reviewed-by: Nicholas Piggin 
---
 arch/powerpc/include/asm/vas.h  | 16 +--
 arch/powerpc/platforms/book3s/vas-api.c | 53 +
 arch/powerpc/platforms/powernv/vas-window.c | 45 -
 arch/powerpc/platforms/powernv/vas.h|  2 +
 4 files changed, 91 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h
index 6076adf9ab4f..163a8bb85d02 100644
--- a/arch/powerpc/include/asm/vas.h
+++ b/arch/powerpc/include/asm/vas.h
@@ -5,6 +5,7 @@
 
 #ifndef _ASM_POWERPC_VAS_H
 #define _ASM_POWERPC_VAS_H
+#include 
 
 struct vas_window;
 
@@ -48,6 +49,16 @@ enum vas_cop_type {
VAS_COP_TYPE_MAX,
 };
 
+/*
+ * User space window operations used for powernv and powerVM
+ */
+struct vas_user_win_ops {
+   struct vas_window * (*open_win)(int vas_id, u64 flags,
+   enum vas_cop_type);
+   u64 (*paste_addr)(struct vas_window *);
+   int (*close_win)(struct vas_window *);
+};
+
 /*
  * Receive window attributes specified by the (in-kernel) owner of window.
  */
@@ -162,8 +173,6 @@ int vas_copy_crb(void *crb, int offset);
  */
 int vas_paste_crb(struct vas_window *win, int offset, bool re);
 
-void vas_win_paste_addr(struct vas_window *window, u64 *addr,
-   int *len);
 int vas_register_api_powernv(struct module *mod, enum vas_cop_type cop_type,
 const char *name);
 void vas_unregister_api_powernv(void);
@@ -177,7 +186,8 @@ void vas_unregister_api_powernv(void);
  * used for others in future.
  */
 int vas_register_coproc_api(struct module *mod, enum vas_cop_type cop_type,
-   const char *name);
+   const char *name,
+   const struct vas_user_win_ops *vops);
 void vas_unregister_coproc_api(void);
 
 #endif /* __ASM_POWERPC_VAS_H */
diff --git a/arch/powerpc/platforms/book3s/vas-api.c 
b/arch/powerpc/platforms/book3s/vas-api.c
index 72c126d87216..ad566464b55b 100644
--- a/arch/powerpc/platforms/book3s/vas-api.c
+++ b/arch/powerpc/platforms/book3s/vas-api.c
@@ -42,6 +42,7 @@ static struct coproc_dev {
dev_t devt;
struct class *class;
enum vas_cop_type cop_type;
+   const struct vas_user_win_ops *vops;
 } coproc_device;
 
 struct coproc_instance {
@@ -72,11 +73,10 @@ static int coproc_open(struct inode *inode, struct file *fp)
 static int coproc_ioc_tx_win_open(struct file *fp, unsigned long arg)
 {
void __user *uptr = (void __user *)arg;
-   struct vas_tx_win_attr txattr = {};
struct vas_tx_win_open_attr uattr;
struct coproc_instance *cp_inst;
struct vas_window *txwin;
-   int rc, vasid;
+   int rc;
 
cp_inst = fp->private_data;
 
@@ -93,27 +93,20 @@ static int coproc_ioc_tx_win_open(struct file *fp, unsigned 
long arg)
}
 
if (uattr.version != 1) {
-   pr_err("Invalid version\n");
+   pr_err("Invalid window open API version\n");
return -EINVAL;
}
 
-   vasid = uattr.vas_id;
-
-   vas_init_tx_win_attr(, cp_inst->coproc->cop_type);
-
-   txattr.lpid = mfspr(SPRN_LPID);
-   txattr.pidr = mfspr(SPRN_PID);
-   txattr.user_win = true;
-   txattr.rsvd_txbuf_count = false;
-   txattr.pswid = false;
-
-   pr_devel("Pid %d: Opening txwin, PIDR %ld\n", txattr.pidr,
-   mfspr(SPRN_PID));
+   if (!cp_inst->coproc->vops && !cp_inst->coproc->vops->open_win) {
+   pr_err("VAS API is not registered\n");
+   return -EACCES;
+   }
 
-   txwin = vas_tx_win_open(vasid, cp_inst->coproc->cop_type, );
+   txwin = cp_inst->coproc->vops->open_win(uattr.vas_id, uattr.flags,
+   cp_inst->coproc->cop_type);
if (IS_ERR(txwin)) {
-   pr_err("%s() vas_tx_win_open() failed, %ld\n", __func__,
-   PTR_ERR(txwin));
+   pr_err("%s() VAS window open failed, %ld\n", __func__,
+   PTR_ERR(txwin));
return PTR_ERR(txwin);
}
 
@@ -125,9 +118,15 @@ static int coproc_ioc_tx_win_open(struct file *fp, 
unsigned long arg)
 static int coproc_release(struct inode *inode, struct file *fp)
 {
struct coproc_instance *cp_inst = fp->private_data;
+   int rc;
 
if (cp_inst->txwin) {
-   vas_win_close(cp_inst->txwin);
+   if (cp_inst->coproc->vops &&
+   cp_inst->coproc->vops->close_win) {
+   rc = cp_inst->coproc->vops->close_win(cp_inst->txwin);
+