On 03.06.19 13:37, Cornelia Huck wrote:
On Wed, 29 May 2019 14:26:51 +0200
Michael Mueller <mimu@xxxxxxxxxxxxx> wrote:
From: Halil Pasic <pasic@xxxxxxxxxxxxx>
To support protected virtualization cio will need to make sure the
memory used for communication with the hypervisor is DMA memory.
Let us introduce one global pool for cio.
Our DMA pools are implemented as a gen_pool backed with DMA pages. The
idea is to avoid each allocation effectively wasting a page, as we
typically allocate much less than PAGE_SIZE.
Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Ott <sebott@xxxxxxxxxxxxx>
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
---
arch/s390/Kconfig | 1 +
arch/s390/include/asm/cio.h | 11 ++++
drivers/s390/cio/css.c | 120 ++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 128 insertions(+), 4 deletions(-)
(...)
diff --git a/arch/s390/include/asm/cio.h b/arch/s390/include/asm/cio.h
index 1727180e8ca1..43c007d2775a 100644
--- a/arch/s390/include/asm/cio.h
+++ b/arch/s390/include/asm/cio.h
@@ -328,6 +328,17 @@ static inline u8 pathmask_to_pos(u8 mask)
void channel_subsystem_reinit(void);
extern void css_schedule_reprobe(void);
+extern void *cio_dma_zalloc(size_t size);
+extern void cio_dma_free(void *cpu_addr, size_t size);
+extern struct device *cio_get_dma_css_dev(void);
+
+struct gen_pool;
That forward declaration is a bit ugly... I guess the alternative was
include hell?
That's an easy one.
#include <linux/bitops.h>
+#include <linux/genalloc.h>
#include <asm/types.h>
+void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
+ size_t size);
+void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size);
+void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev);
+struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages);
+
/* Function from drivers/s390/cio/chsc.c */
int chsc_sstpc(void *page, unsigned int op, u16 ctrl, u64 *clock_delta);
int chsc_sstpi(void *page, void *result, size_t size);
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index aea502922646..b97618497848 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -20,6 +20,8 @@
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/proc_fs.h>
+#include <linux/genalloc.h>
+#include <linux/dma-mapping.h>
#include <asm/isc.h>
#include <asm/crw.h>
@@ -224,6 +226,8 @@ struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
INIT_WORK(&sch->todo_work, css_sch_todo);
sch->dev.release = &css_subchannel_release;
device_initialize(&sch->dev);
It might be helpful to add a comment why you use 31 bit here...
@Halil, please let me know what comment you prefere here...
+ sch->dev.coherent_dma_mask = DMA_BIT_MASK(31);
+ sch->dev.dma_mask = &sch->dev.coherent_dma_mask;
return sch;
err:
@@ -899,6 +903,8 @@ static int __init setup_css(int nr)
dev_set_name(&css->device, "css%x", nr);
css->device.groups = cssdev_attr_groups;
css->device.release = channel_subsystem_release;
...and 64 bit here.
and here.
+ css->device.coherent_dma_mask = DMA_BIT_MASK(64);
+ css->device.dma_mask = &css->device.coherent_dma_mask;
mutex_init(&css->mutex);
css->cssid = chsc_get_cssid(nr);
(...)
@@ -1059,16 +1168,19 @@ static int __init css_bus_init(void)
if (ret)
goto out_unregister;
ret = register_pm_notifier(&css_power_notifier);
- if (ret) {
- unregister_reboot_notifier(&css_reboot_notifier);
- goto out_unregister;
- }
+ if (ret)
+ goto out_unregister_rn;
+ ret = cio_dma_pool_init();
+ if (ret)
+ goto out_unregister_rn;
Don't you also need to unregister the pm notifier on failure here?
Mmh, that was the original intention. Thanks!
Other than that, I noticed only cosmetic issues; seems reasonable to me.
css_init_done = 1;
/* Enable default isc for I/O subchannels. */
isc_register(IO_SCH_ISC);
return 0;
+out_unregister_rn:
+ unregister_reboot_notifier(&css_reboot_notifier);
out_unregister:
while (i-- > 0) {
struct channel_subsystem *css = channel_subsystems[i];
Thanks,
Michael
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