On Wed, 29 May 2019 14:26:51 +0200 Michael Mueller <mimu at linux.ibm.com> wrote:> From: Halil Pasic <pasic at linux.ibm.com> > > 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 at linux.ibm.com> > Reviewed-by: Sebastian Ott <sebott at linux.ibm.com> > Signed-off-by: Michael Mueller <mimu at linux.ibm.com> > --- > 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?> +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...> + 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.> + 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? 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];
On 03.06.19 13:37, Cornelia Huck wrote:> On Wed, 29 May 2019 14:26:51 +0200 > Michael Mueller <mimu at linux.ibm.com> wrote: > >> From: Halil Pasic <pasic at linux.ibm.com> >> >> 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 at linux.ibm.com> >> Reviewed-by: Sebastian Ott <sebott at linux.ibm.com> >> Signed-off-by: Michael Mueller <mimu at linux.ibm.com> >> --- >> 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
On Mon, 3 Jun 2019 13:37:45 +0200 Cornelia Huck <cohuck at redhat.com> wrote:> On Wed, 29 May 2019 14:26:51 +0200 > Michael Mueller <mimu at linux.ibm.com> wrote: > > > From: Halil Pasic <pasic at linux.ibm.com> > > > > 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 at linux.ibm.com> > > Reviewed-by: Sebastian Ott <sebott at linux.ibm.com> > > Signed-off-by: Michael Mueller <mimu at linux.ibm.com> > > --- > > 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...Can you explain to me what is ugly about it so I can avoid similar mistakes in the future?>I guess the alternative was > include hell? >What do you mean by include hell? I decided to use a forward declaration because the guys that include "cio.h" are not expected to require the interfaces defined in linux/genalloc.h. My motivation to do it like this was the principle of encapsulation. Regards, Halil
On Mon, 3 Jun 2019 14:09:02 +0200 Michael Mueller <mimu at linux.ibm.com> wrote:> >> @@ -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... >How about? /* * The physical addresses of some the dma structures that * can belong to a subchannel need to fit 31 bit width (examples ccw,). */> > > >> + 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./* * We currently allocate notifier bits with this (using css->device * as the device argument with the DMA API), and are fine with 64 bit * addresses. */ Regards, Halil
On Mon, 3 Jun 2019 14:47:06 +0200 Halil Pasic <pasic at linux.ibm.com> wrote:> On Mon, 3 Jun 2019 13:37:45 +0200 > Cornelia Huck <cohuck at redhat.com> wrote: > > > On Wed, 29 May 2019 14:26:51 +0200 > > Michael Mueller <mimu at linux.ibm.com> wrote:> > > 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... > > Can you explain to me what is ugly about it so I can avoid similar > mistakes in the future? > > >I guess the alternative was > > include hell? > > > > What do you mean by include hell? > > I decided to use a forward declaration because the guys that include > "cio.h" are not expected to require the interfaces defined in > linux/genalloc.h. My motivation to do it like this was the principle of > encapsulation.My personal rule-of-thumb is to include the header if it is straightforward enough (e.g. if adding a basic header is enough). If you need to include a header together with all of its friends and family, a forward declaration is probably nicer. And of course, sometimes it is simply needed.
On Mon, 3 Jun 2019 14:09:02 +0200 Michael Mueller <mimu at linux.ibm.com> wrote:> >> @@ -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!I suppose we could also move cio_dma_pool_init() right before the register_reboot_notifier() call and goto out_unregister on error. Regards, Halil
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