| Message ID | 20130221191431.4318f949@gondolin |
|---|---|
| State | New |
| Headers | show |
On Thu, Feb 21, 2013 at 07:14:31PM +0100, Cornelia Huck wrote: > On Thu, 21 Feb 2013 18:34:59 +0200 > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > On Thu, Feb 21, 2013 at 04:21:43PM +0100, Cornelia Huck wrote: > > > On Thu, 21 Feb 2013 16:39:05 +0200 > > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > > > On Thu, Feb 21, 2013 at 02:13:00PM +0100, Cornelia Huck wrote: > > > > > As s390 doesn't use memory writes for virtio notifcations, create > > > > > a special kind of ioeventfd instead that hooks up into diagnose > > > > > 0x500 (kvm hypercall) with function code 3 (virtio-ccw notification). > > > > > > > > > > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> > > > > > > > > Do we really have to put virtio specific stuff into kvm? > > > > How about we add generic functionality to match GPRs > > > > on a hypercall and signal an eventfd? > > > > > > Worth a try implementing that. > > > > > > > > > > > Also, it's a bit unfortunate that this doesn't use > > > > the io bus datastructure, long term the linked list handling > > > > might become a bottleneck, using shared code this could maybe > > > > benefit from performance optimizations there. > > > > > > The linked list stuff was more like an initial implementation that > > > could be improved later. > > > > > > > io bus data structure currently has the ability to match on > > > > two 64 bit fields (addr/datamatch) and a signed 32 bit one (length). > > > > Isn't this sufficient for your purposes? > > > > How about sticking subchannel id in address, vq in data match > > > > and using io bus? > > > > > > I can give that a try. (I must admit that I didn't look at the iobus > > > stuff in detail.) > > > > > > > > > > > BTW maybe we could do this for the user interface too, > > > > while I'm not 100% sure it's the cleanest thing to do > > > > (or will work), it would certainly minimize the patchset. > > > > > > You mean integrating with the generic interface and dropping the new > > > ARCH flag? > > > > Not sure about the flag but we could use the general structure > > without an arch-specific format, if that's a good fit. > > > So I have something that seems to do what I want. I'll see if I can > morph it into something presentable tomorrow. > > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > index b58dd86..3c43e30 100644 > --- a/arch/s390/kvm/Kconfig > +++ b/arch/s390/kvm/Kconfig > @@ -22,6 +22,7 @@ config KVM > select PREEMPT_NOTIFIERS > select ANON_INODES > select HAVE_KVM_CPU_RELAX_INTERCEPT > + select HAVE_KVM_EVENTFD > ---help--- > Support hosting paravirtualized guest machines using the SIE > virtualization capability on the mainframe. This should work > diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile > index 3975722..8fe9d65 100644 > --- a/arch/s390/kvm/Makefile > +++ b/arch/s390/kvm/Makefile > @@ -6,7 +6,7 @@ > # it under the terms of the GNU General Public License (version 2 only) > # as published by the Free Software Foundation. > > -common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o) > +common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o eventfd.o) > > ccflags-y := -Ivirt/kvm -Iarch/s390/kvm > > diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c > index a390687..7fc195e 100644 > --- a/arch/s390/kvm/diag.c > +++ b/arch/s390/kvm/diag.c > @@ -104,6 +104,20 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) > return -EREMOTE; > } > > +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) > +{ > + int ret, idx; > + u64 vq = vcpu->run->s.regs.gprs[3]; > + > + idx = srcu_read_lock(&vcpu->kvm->srcu); > + ret = kvm_io_bus_write(vcpu->kvm, KVM_CSS_BUS, > + vcpu->run->s.regs.gprs[2], > + vcpu->run->s.regs.gprs[1], > + &vq); Hmm, do you really need three gprs? If not, we could just pass len == 8, which would be cleaner. Also might as well drop the vq variable, no? > + srcu_read_unlock(&vcpu->kvm->srcu, idx); > + return ret; > +} > + > int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > { > int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16; > @@ -118,6 +132,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > return __diag_time_slice_end_directed(vcpu); > case 0x308: > return __diag_ipl_functions(vcpu); > + case 0x500: > + return __diag_virtio_hypercall(vcpu); > default: > return -EOPNOTSUPP; > } > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > index f822d36..04d2454 100644 > --- a/arch/s390/kvm/kvm-s390.c > +++ b/arch/s390/kvm/kvm-s390.c > @@ -142,6 +142,7 @@ int kvm_dev_ioctl_check_extension(long ext) > case KVM_CAP_ONE_REG: > case KVM_CAP_ENABLE_CAP: > case KVM_CAP_S390_CSS_SUPPORT: > + case KVM_CAP_IOEVENTFD: > r = 1; > break; > case KVM_CAP_NR_VCPUS: > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 3b768ef..59be516 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -148,6 +148,7 @@ struct kvm_io_bus { > enum kvm_bus { > KVM_MMIO_BUS, > KVM_PIO_BUS, > + KVM_CSS_BUS, > KVM_NR_BUSES > }; > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 9a2db57..1df0766 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -448,12 +448,14 @@ enum { > kvm_ioeventfd_flag_nr_datamatch, > kvm_ioeventfd_flag_nr_pio, > kvm_ioeventfd_flag_nr_deassign, > + kvm_ioeventfd_flag_nr_css, > kvm_ioeventfd_flag_nr_max, > }; > > #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) > #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) > #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) > +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css) > > #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1) > > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > index f0ced1a..57a06ff 100644 > --- a/virt/kvm/eventfd.c > +++ b/virt/kvm/eventfd.c > @@ -576,6 +576,7 @@ struct _ioeventfd { > u64 datamatch; > struct kvm_io_device dev; > bool wildcard; > + bool is_css; > }; > > static inline struct _ioeventfd * > @@ -607,24 +608,27 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) > > /* otherwise, we have to actually compare the data */ > > - BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > - > - switch (len) { > - case 1: > - _val = *(u8 *)val; > - break; > - case 2: > - _val = *(u16 *)val; > - break; > - case 4: > - _val = *(u32 *)val; > - break; > - case 8: > + if (!p->is_css) { > + BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > + > + switch (len) { > + case 1: > + _val = *(u8 *)val; > + break; > + case 2: > + _val = *(u16 *)val; > + break; > + case 4: > + _val = *(u32 *)val; > + break; > + case 8: > + _val = *(u64 *)val; > + break; > + default: > + return false; > + } > + } else > _val = *(u64 *)val; > - break; > - default: > - return false; > - } > > return _val == p->datamatch ? true : false; > } > @@ -679,25 +683,29 @@ static int > kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > { > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > + enum kvm_bus bus_idx; > struct _ioeventfd *p; > struct eventfd_ctx *eventfd; > int ret; > > - /* must be natural-word sized */ > - switch (args->len) { > - case 1: > - case 2: > - case 4: > - case 8: > - break; > - default: > - return -EINVAL; > - } > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > + if (!css) { > + /* must be natural-word sized */ > + switch (args->len) { > + case 1: > + case 2: > + case 4: > + case 8: > + break; > + default: > + return -EINVAL; > + } > > - /* check for range overflow */ > - if (args->addr + args->len < args->addr) > - return -EINVAL; > + /* check for range overflow */ > + if (args->addr + args->len < args->addr) > + return -EINVAL; > + } > > /* check for extra flags that we don't understand */ > if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) > @@ -717,6 +725,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > p->addr = args->addr; > p->length = args->len; > p->eventfd = eventfd; > + p->is_css = css; > > /* The datamatch feature is optional, otherwise this is a wildcard */ > if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) > @@ -759,11 +768,13 @@ static int > kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > { > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > + enum kvm_bus bus_idx; > struct _ioeventfd *p, *tmp; > struct eventfd_ctx *eventfd; > int ret = -ENOENT; > > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > eventfd = eventfd_ctx_fdget(args->fd); > if (IS_ERR(eventfd)) > return PTR_ERR(eventfd);
On Thu, 21 Feb 2013 22:42:41 +0200 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Thu, Feb 21, 2013 at 07:14:31PM +0100, Cornelia Huck wrote: > > On Thu, 21 Feb 2013 18:34:59 +0200 > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > On Thu, Feb 21, 2013 at 04:21:43PM +0100, Cornelia Huck wrote: > > > > On Thu, 21 Feb 2013 16:39:05 +0200 > > > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > > > > > On Thu, Feb 21, 2013 at 02:13:00PM +0100, Cornelia Huck wrote: > > > > > > As s390 doesn't use memory writes for virtio notifcations, create > > > > > > a special kind of ioeventfd instead that hooks up into diagnose > > > > > > 0x500 (kvm hypercall) with function code 3 (virtio-ccw notification). > > > > > > > > > > > > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> > > > > > > > > > > Do we really have to put virtio specific stuff into kvm? > > > > > How about we add generic functionality to match GPRs > > > > > on a hypercall and signal an eventfd? > > > > > > > > Worth a try implementing that. > > > > > > > > > > > > > > Also, it's a bit unfortunate that this doesn't use > > > > > the io bus datastructure, long term the linked list handling > > > > > might become a bottleneck, using shared code this could maybe > > > > > benefit from performance optimizations there. > > > > > > > > The linked list stuff was more like an initial implementation that > > > > could be improved later. > > > > > > > > > io bus data structure currently has the ability to match on > > > > > two 64 bit fields (addr/datamatch) and a signed 32 bit one (length). > > > > > Isn't this sufficient for your purposes? > > > > > How about sticking subchannel id in address, vq in data match > > > > > and using io bus? > > > > > > > > I can give that a try. (I must admit that I didn't look at the iobus > > > > stuff in detail.) > > > > > > > > > > > > > > BTW maybe we could do this for the user interface too, > > > > > while I'm not 100% sure it's the cleanest thing to do > > > > > (or will work), it would certainly minimize the patchset. > > > > > > > > You mean integrating with the generic interface and dropping the new > > > > ARCH flag? > > > > > > Not sure about the flag but we could use the general structure > > > without an arch-specific format, if that's a good fit. > > > > > So I have something that seems to do what I want. I'll see if I can > > morph it into something presentable tomorrow. > > > > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > > index b58dd86..3c43e30 100644 > > --- a/arch/s390/kvm/Kconfig > > +++ b/arch/s390/kvm/Kconfig > > @@ -22,6 +22,7 @@ config KVM > > select PREEMPT_NOTIFIERS > > select ANON_INODES > > select HAVE_KVM_CPU_RELAX_INTERCEPT > > + select HAVE_KVM_EVENTFD > > ---help--- > > Support hosting paravirtualized guest machines using the SIE > > virtualization capability on the mainframe. This should work > > diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile > > index 3975722..8fe9d65 100644 > > --- a/arch/s390/kvm/Makefile > > +++ b/arch/s390/kvm/Makefile > > @@ -6,7 +6,7 @@ > > # it under the terms of the GNU General Public License (version 2 only) > > # as published by the Free Software Foundation. > > > > -common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o) > > +common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o eventfd.o) > > > > ccflags-y := -Ivirt/kvm -Iarch/s390/kvm > > > > diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c > > index a390687..7fc195e 100644 > > --- a/arch/s390/kvm/diag.c > > +++ b/arch/s390/kvm/diag.c > > @@ -104,6 +104,20 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) > > return -EREMOTE; > > } > > > > +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) > > +{ > > + int ret, idx; > > + u64 vq = vcpu->run->s.regs.gprs[3]; > > + > > + idx = srcu_read_lock(&vcpu->kvm->srcu); > > + ret = kvm_io_bus_write(vcpu->kvm, KVM_CSS_BUS, > > + vcpu->run->s.regs.gprs[2], > > + vcpu->run->s.regs.gprs[1], > > + &vq); > > Hmm, do you really need three gprs? If not, we could > just pass len == 8, which would be cleaner. > Also might as well drop the vq variable, no? If I want to pass generic hypercalls, I need to pass the subcode (in gpr 1) in the len variable. If all we'll ever need is the virtio-ccw notify hypercall, gprs 2 and 3 are enough. Would perhaps make the common code less hacky, but we'd lose (unneeded?) flexibility. > > > + srcu_read_unlock(&vcpu->kvm->srcu, idx); > > + return ret; > > +} > > + > > int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > > { > > int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16; > > @@ -118,6 +132,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > > return __diag_time_slice_end_directed(vcpu); > > case 0x308: > > return __diag_ipl_functions(vcpu); > > + case 0x500: > > + return __diag_virtio_hypercall(vcpu); > > default: > > return -EOPNOTSUPP; > > } > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > > index f822d36..04d2454 100644 > > --- a/arch/s390/kvm/kvm-s390.c > > +++ b/arch/s390/kvm/kvm-s390.c > > @@ -142,6 +142,7 @@ int kvm_dev_ioctl_check_extension(long ext) > > case KVM_CAP_ONE_REG: > > case KVM_CAP_ENABLE_CAP: > > case KVM_CAP_S390_CSS_SUPPORT: > > + case KVM_CAP_IOEVENTFD: > > r = 1; > > break; > > case KVM_CAP_NR_VCPUS: > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index 3b768ef..59be516 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -148,6 +148,7 @@ struct kvm_io_bus { > > enum kvm_bus { > > KVM_MMIO_BUS, > > KVM_PIO_BUS, > > + KVM_CSS_BUS, > > KVM_NR_BUSES > > }; > > > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > > index 9a2db57..1df0766 100644 > > --- a/include/uapi/linux/kvm.h > > +++ b/include/uapi/linux/kvm.h > > @@ -448,12 +448,14 @@ enum { > > kvm_ioeventfd_flag_nr_datamatch, > > kvm_ioeventfd_flag_nr_pio, > > kvm_ioeventfd_flag_nr_deassign, > > + kvm_ioeventfd_flag_nr_css, > > kvm_ioeventfd_flag_nr_max, > > }; > > > > #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) > > #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) > > #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) > > +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css) > > > > #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1) > > > > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > > index f0ced1a..57a06ff 100644 > > --- a/virt/kvm/eventfd.c > > +++ b/virt/kvm/eventfd.c > > @@ -576,6 +576,7 @@ struct _ioeventfd { > > u64 datamatch; > > struct kvm_io_device dev; > > bool wildcard; > > + bool is_css; > > }; > > > > static inline struct _ioeventfd * > > @@ -607,24 +608,27 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) > > > > /* otherwise, we have to actually compare the data */ > > > > - BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > > - > > - switch (len) { > > - case 1: > > - _val = *(u8 *)val; > > - break; > > - case 2: > > - _val = *(u16 *)val; > > - break; > > - case 4: > > - _val = *(u32 *)val; > > - break; > > - case 8: > > + if (!p->is_css) { > > + BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > > + > > + switch (len) { > > + case 1: > > + _val = *(u8 *)val; > > + break; > > + case 2: > > + _val = *(u16 *)val; > > + break; > > + case 4: > > + _val = *(u32 *)val; > > + break; > > + case 8: > > + _val = *(u64 *)val; > > + break; > > + default: > > + return false; > > + } > > + } else > > _val = *(u64 *)val; > > - break; > > - default: > > - return false; > > - } > > > > return _val == p->datamatch ? true : false; > > } > > @@ -679,25 +683,29 @@ static int > > kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > { > > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > > + enum kvm_bus bus_idx; > > struct _ioeventfd *p; > > struct eventfd_ctx *eventfd; > > int ret; > > > > - /* must be natural-word sized */ > > - switch (args->len) { > > - case 1: > > - case 2: > > - case 4: > > - case 8: > > - break; > > - default: > > - return -EINVAL; > > - } > > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > > + if (!css) { > > + /* must be natural-word sized */ > > + switch (args->len) { > > + case 1: > > + case 2: > > + case 4: > > + case 8: > > + break; > > + default: > > + return -EINVAL; > > + } > > > > - /* check for range overflow */ > > - if (args->addr + args->len < args->addr) > > - return -EINVAL; > > + /* check for range overflow */ > > + if (args->addr + args->len < args->addr) > > + return -EINVAL; > > + } > > > > /* check for extra flags that we don't understand */ > > if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) > > @@ -717,6 +725,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > p->addr = args->addr; > > p->length = args->len; > > p->eventfd = eventfd; > > + p->is_css = css; > > > > /* The datamatch feature is optional, otherwise this is a wildcard */ > > if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) > > @@ -759,11 +768,13 @@ static int > > kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > { > > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > > + enum kvm_bus bus_idx; > > struct _ioeventfd *p, *tmp; > > struct eventfd_ctx *eventfd; > > int ret = -ENOENT; > > > > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > > eventfd = eventfd_ctx_fdget(args->fd); > > if (IS_ERR(eventfd)) > > return PTR_ERR(eventfd); >
On Fri, Feb 22, 2013 at 08:22:08AM +0100, Cornelia Huck wrote: > On Thu, 21 Feb 2013 22:42:41 +0200 > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > On Thu, Feb 21, 2013 at 07:14:31PM +0100, Cornelia Huck wrote: > > > On Thu, 21 Feb 2013 18:34:59 +0200 > > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > > > On Thu, Feb 21, 2013 at 04:21:43PM +0100, Cornelia Huck wrote: > > > > > On Thu, 21 Feb 2013 16:39:05 +0200 > > > > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > > > > > > > On Thu, Feb 21, 2013 at 02:13:00PM +0100, Cornelia Huck wrote: > > > > > > > As s390 doesn't use memory writes for virtio notifcations, create > > > > > > > a special kind of ioeventfd instead that hooks up into diagnose > > > > > > > 0x500 (kvm hypercall) with function code 3 (virtio-ccw notification). > > > > > > > > > > > > > > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> > > > > > > > > > > > > Do we really have to put virtio specific stuff into kvm? > > > > > > How about we add generic functionality to match GPRs > > > > > > on a hypercall and signal an eventfd? > > > > > > > > > > Worth a try implementing that. > > > > > > > > > > > > > > > > > Also, it's a bit unfortunate that this doesn't use > > > > > > the io bus datastructure, long term the linked list handling > > > > > > might become a bottleneck, using shared code this could maybe > > > > > > benefit from performance optimizations there. > > > > > > > > > > The linked list stuff was more like an initial implementation that > > > > > could be improved later. > > > > > > > > > > > io bus data structure currently has the ability to match on > > > > > > two 64 bit fields (addr/datamatch) and a signed 32 bit one (length). > > > > > > Isn't this sufficient for your purposes? > > > > > > How about sticking subchannel id in address, vq in data match > > > > > > and using io bus? > > > > > > > > > > I can give that a try. (I must admit that I didn't look at the iobus > > > > > stuff in detail.) > > > > > > > > > > > > > > > > > BTW maybe we could do this for the user interface too, > > > > > > while I'm not 100% sure it's the cleanest thing to do > > > > > > (or will work), it would certainly minimize the patchset. > > > > > > > > > > You mean integrating with the generic interface and dropping the new > > > > > ARCH flag? > > > > > > > > Not sure about the flag but we could use the general structure > > > > without an arch-specific format, if that's a good fit. > > > > > > > So I have something that seems to do what I want. I'll see if I can > > > morph it into something presentable tomorrow. > > > > > > diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig > > > index b58dd86..3c43e30 100644 > > > --- a/arch/s390/kvm/Kconfig > > > +++ b/arch/s390/kvm/Kconfig > > > @@ -22,6 +22,7 @@ config KVM > > > select PREEMPT_NOTIFIERS > > > select ANON_INODES > > > select HAVE_KVM_CPU_RELAX_INTERCEPT > > > + select HAVE_KVM_EVENTFD > > > ---help--- > > > Support hosting paravirtualized guest machines using the SIE > > > virtualization capability on the mainframe. This should work > > > diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile > > > index 3975722..8fe9d65 100644 > > > --- a/arch/s390/kvm/Makefile > > > +++ b/arch/s390/kvm/Makefile > > > @@ -6,7 +6,7 @@ > > > # it under the terms of the GNU General Public License (version 2 only) > > > # as published by the Free Software Foundation. > > > > > > -common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o) > > > +common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o eventfd.o) > > > > > > ccflags-y := -Ivirt/kvm -Iarch/s390/kvm > > > > > > diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c > > > index a390687..7fc195e 100644 > > > --- a/arch/s390/kvm/diag.c > > > +++ b/arch/s390/kvm/diag.c > > > @@ -104,6 +104,20 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) > > > return -EREMOTE; > > > } > > > > > > +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) > > > +{ > > > + int ret, idx; > > > + u64 vq = vcpu->run->s.regs.gprs[3]; > > > + > > > + idx = srcu_read_lock(&vcpu->kvm->srcu); > > > + ret = kvm_io_bus_write(vcpu->kvm, KVM_CSS_BUS, > > > + vcpu->run->s.regs.gprs[2], > > > + vcpu->run->s.regs.gprs[1], > > > + &vq); > > > > Hmm, do you really need three gprs? If not, we could > > just pass len == 8, which would be cleaner. > > Also might as well drop the vq variable, no? > > If I want to pass generic hypercalls, I need to pass the subcode (in > gpr 1) in the len variable. If all we'll ever need is the virtio-ccw > notify hypercall, gprs 2 and 3 are enough. Would perhaps make the > common code less hacky, but we'd lose (unneeded?) flexibility. I see. I'm fine with either way, but I note the code above can overflow int len, which is likely not what you want. > > > > > + srcu_read_unlock(&vcpu->kvm->srcu, idx); > > > + return ret; > > > +} > > > + > > > int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > > > { > > > int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16; > > > @@ -118,6 +132,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) > > > return __diag_time_slice_end_directed(vcpu); > > > case 0x308: > > > return __diag_ipl_functions(vcpu); > > > + case 0x500: > > > + return __diag_virtio_hypercall(vcpu); > > > default: > > > return -EOPNOTSUPP; > > > } > > > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c > > > index f822d36..04d2454 100644 > > > --- a/arch/s390/kvm/kvm-s390.c > > > +++ b/arch/s390/kvm/kvm-s390.c > > > @@ -142,6 +142,7 @@ int kvm_dev_ioctl_check_extension(long ext) > > > case KVM_CAP_ONE_REG: > > > case KVM_CAP_ENABLE_CAP: > > > case KVM_CAP_S390_CSS_SUPPORT: > > > + case KVM_CAP_IOEVENTFD: > > > r = 1; > > > break; > > > case KVM_CAP_NR_VCPUS: > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > > index 3b768ef..59be516 100644 > > > --- a/include/linux/kvm_host.h > > > +++ b/include/linux/kvm_host.h > > > @@ -148,6 +148,7 @@ struct kvm_io_bus { > > > enum kvm_bus { > > > KVM_MMIO_BUS, > > > KVM_PIO_BUS, > > > + KVM_CSS_BUS, > > > KVM_NR_BUSES > > > }; > > > > > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > > > index 9a2db57..1df0766 100644 > > > --- a/include/uapi/linux/kvm.h > > > +++ b/include/uapi/linux/kvm.h > > > @@ -448,12 +448,14 @@ enum { > > > kvm_ioeventfd_flag_nr_datamatch, > > > kvm_ioeventfd_flag_nr_pio, > > > kvm_ioeventfd_flag_nr_deassign, > > > + kvm_ioeventfd_flag_nr_css, > > > kvm_ioeventfd_flag_nr_max, > > > }; > > > > > > #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) > > > #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) > > > #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) > > > +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css) > > > > > > #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1) > > > > > > diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c > > > index f0ced1a..57a06ff 100644 > > > --- a/virt/kvm/eventfd.c > > > +++ b/virt/kvm/eventfd.c > > > @@ -576,6 +576,7 @@ struct _ioeventfd { > > > u64 datamatch; > > > struct kvm_io_device dev; > > > bool wildcard; > > > + bool is_css; > > > }; > > > > > > static inline struct _ioeventfd * > > > @@ -607,24 +608,27 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) > > > > > > /* otherwise, we have to actually compare the data */ > > > > > > - BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > > > - > > > - switch (len) { > > > - case 1: > > > - _val = *(u8 *)val; > > > - break; > > > - case 2: > > > - _val = *(u16 *)val; > > > - break; > > > - case 4: > > > - _val = *(u32 *)val; > > > - break; > > > - case 8: > > > + if (!p->is_css) { > > > + BUG_ON(!IS_ALIGNED((unsigned long)val, len)); > > > + > > > + switch (len) { > > > + case 1: > > > + _val = *(u8 *)val; > > > + break; > > > + case 2: > > > + _val = *(u16 *)val; > > > + break; > > > + case 4: > > > + _val = *(u32 *)val; > > > + break; > > > + case 8: > > > + _val = *(u64 *)val; > > > + break; > > > + default: > > > + return false; > > > + } > > > + } else > > > _val = *(u64 *)val; > > > - break; > > > - default: > > > - return false; > > > - } > > > > > > return _val == p->datamatch ? true : false; > > > } > > > @@ -679,25 +683,29 @@ static int > > > kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > > { > > > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > > > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > > > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > > > + enum kvm_bus bus_idx; > > > struct _ioeventfd *p; > > > struct eventfd_ctx *eventfd; > > > int ret; > > > > > > - /* must be natural-word sized */ > > > - switch (args->len) { > > > - case 1: > > > - case 2: > > > - case 4: > > > - case 8: > > > - break; > > > - default: > > > - return -EINVAL; > > > - } > > > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > > > + if (!css) { > > > + /* must be natural-word sized */ > > > + switch (args->len) { > > > + case 1: > > > + case 2: > > > + case 4: > > > + case 8: > > > + break; > > > + default: > > > + return -EINVAL; > > > + } > > > > > > - /* check for range overflow */ > > > - if (args->addr + args->len < args->addr) > > > - return -EINVAL; > > > + /* check for range overflow */ > > > + if (args->addr + args->len < args->addr) > > > + return -EINVAL; > > > + } > > > > > > /* check for extra flags that we don't understand */ > > > if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) > > > @@ -717,6 +725,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > > p->addr = args->addr; > > > p->length = args->len; > > > p->eventfd = eventfd; > > > + p->is_css = css; > > > > > > /* The datamatch feature is optional, otherwise this is a wildcard */ > > > if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) > > > @@ -759,11 +768,13 @@ static int > > > kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) > > > { > > > int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; > > > - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; > > > + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; > > > + enum kvm_bus bus_idx; > > > struct _ioeventfd *p, *tmp; > > > struct eventfd_ctx *eventfd; > > > int ret = -ENOENT; > > > > > > + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; > > > eventfd = eventfd_ctx_fdget(args->fd); > > > if (IS_ERR(eventfd)) > > > return PTR_ERR(eventfd); > >
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index b58dd86..3c43e30 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -22,6 +22,7 @@ config KVM select PREEMPT_NOTIFIERS select ANON_INODES select HAVE_KVM_CPU_RELAX_INTERCEPT + select HAVE_KVM_EVENTFD ---help--- Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile index 3975722..8fe9d65 100644 --- a/arch/s390/kvm/Makefile +++ b/arch/s390/kvm/Makefile @@ -6,7 +6,7 @@ # it under the terms of the GNU General Public License (version 2 only) # as published by the Free Software Foundation. -common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o) +common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o eventfd.o) ccflags-y := -Ivirt/kvm -Iarch/s390/kvm diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index a390687..7fc195e 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -104,6 +104,20 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) return -EREMOTE; } +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) +{ + int ret, idx; + u64 vq = vcpu->run->s.regs.gprs[3]; + + idx = srcu_read_lock(&vcpu->kvm->srcu); + ret = kvm_io_bus_write(vcpu->kvm, KVM_CSS_BUS, + vcpu->run->s.regs.gprs[2], + vcpu->run->s.regs.gprs[1], + &vq); + srcu_read_unlock(&vcpu->kvm->srcu, idx); + return ret; +} + int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) { int code = (vcpu->arch.sie_block->ipb & 0xfff0000) >> 16; @@ -118,6 +132,8 @@ int kvm_s390_handle_diag(struct kvm_vcpu *vcpu) return __diag_time_slice_end_directed(vcpu); case 0x308: return __diag_ipl_functions(vcpu); + case 0x500: + return __diag_virtio_hypercall(vcpu); default: return -EOPNOTSUPP; } diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index f822d36..04d2454 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -142,6 +142,7 @@ int kvm_dev_ioctl_check_extension(long ext) case KVM_CAP_ONE_REG: case KVM_CAP_ENABLE_CAP: case KVM_CAP_S390_CSS_SUPPORT: + case KVM_CAP_IOEVENTFD: r = 1; break; case KVM_CAP_NR_VCPUS: diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 3b768ef..59be516 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -148,6 +148,7 @@ struct kvm_io_bus { enum kvm_bus { KVM_MMIO_BUS, KVM_PIO_BUS, + KVM_CSS_BUS, KVM_NR_BUSES }; diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 9a2db57..1df0766 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -448,12 +448,14 @@ enum { kvm_ioeventfd_flag_nr_datamatch, kvm_ioeventfd_flag_nr_pio, kvm_ioeventfd_flag_nr_deassign, + kvm_ioeventfd_flag_nr_css, kvm_ioeventfd_flag_nr_max, }; #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css) #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1) diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index f0ced1a..57a06ff 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -576,6 +576,7 @@ struct _ioeventfd { u64 datamatch; struct kvm_io_device dev; bool wildcard; + bool is_css; }; static inline struct _ioeventfd * @@ -607,24 +608,27 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) /* otherwise, we have to actually compare the data */ - BUG_ON(!IS_ALIGNED((unsigned long)val, len)); - - switch (len) { - case 1: - _val = *(u8 *)val; - break; - case 2: - _val = *(u16 *)val; - break; - case 4: - _val = *(u32 *)val; - break; - case 8: + if (!p->is_css) { + BUG_ON(!IS_ALIGNED((unsigned long)val, len)); + + switch (len) { + case 1: + _val = *(u8 *)val; + break; + case 2: + _val = *(u16 *)val; + break; + case 4: + _val = *(u32 *)val; + break; + case 8: + _val = *(u64 *)val; + break; + default: + return false; + } + } else _val = *(u64 *)val; - break; - default: - return false; - } return _val == p->datamatch ? true : false; } @@ -679,25 +683,29 @@ static int kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) { int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; + enum kvm_bus bus_idx; struct _ioeventfd *p; struct eventfd_ctx *eventfd; int ret; - /* must be natural-word sized */ - switch (args->len) { - case 1: - case 2: - case 4: - case 8: - break; - default: - return -EINVAL; - } + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; + if (!css) { + /* must be natural-word sized */ + switch (args->len) { + case 1: + case 2: + case 4: + case 8: + break; + default: + return -EINVAL; + } - /* check for range overflow */ - if (args->addr + args->len < args->addr) - return -EINVAL; + /* check for range overflow */ + if (args->addr + args->len < args->addr) + return -EINVAL; + } /* check for extra flags that we don't understand */ if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) @@ -717,6 +725,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) p->addr = args->addr; p->length = args->len; p->eventfd = eventfd; + p->is_css = css; /* The datamatch feature is optional, otherwise this is a wildcard */ if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) @@ -759,11 +768,13 @@ static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) { int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO; - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS; + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS; + enum kvm_bus bus_idx; struct _ioeventfd *p, *tmp; struct eventfd_ctx *eventfd; int ret = -ENOENT; + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS; eventfd = eventfd_ctx_fdget(args->fd); if (IS_ERR(eventfd)) return PTR_ERR(eventfd);