On Mon, 4 Mar 2013 21:07:41 -0300
Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote:
> On Thu, Feb 28, 2013 at 12:33:21PM +0100, Cornelia Huck wrote:
> > Enable ioeventfd support on s390 and hook up diagnose 500 virtio-ccw
> > notifications.
> >
> > Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
> > ---
> > arch/s390/kvm/Kconfig | 1 +
> > arch/s390/kvm/Makefile | 2 +-
> > arch/s390/kvm/diag.c | 26 ++++++++++++++++++++++++++
> > arch/s390/kvm/kvm-s390.c | 1 +
> > 4 files changed, 29 insertions(+), 1 deletion(-)
> >
> > 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..1c01a99 100644
> > --- a/arch/s390/kvm/diag.c
> > +++ b/arch/s390/kvm/diag.c
> > @@ -13,6 +13,7 @@
> >
> > #include <linux/kvm.h>
> > #include <linux/kvm_host.h>
> > +#include <asm/virtio-ccw.h>
> > #include "kvm-s390.h"
> > #include "trace.h"
> > #include "trace-s390.h"
> > @@ -104,6 +105,29 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
> > return -EREMOTE;
> > }
> >
> > +static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
> > +{
> > + int ret, idx;
> > +
> > + /* No virtio-ccw notification? Get out quickly. */
> > + if (!vcpu->kvm->arch.css_support ||
> > + (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
> > + return -EOPNOTSUPP;
> > +
> > + idx = srcu_read_lock(&vcpu->kvm->srcu);
> > + /*
> > + * The layout is as follows:
> > + * - gpr 2 contains the subchannel id (passed as addr)
> > + * - gpr 3 contains the virtqueue index (passed as datamatch)
> > + */
> > + ret = kvm_io_bus_write(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
> > + vcpu->run->s.regs.gprs[2],
> > + 8, &vcpu->run->s.regs.gprs[3]);
> > + srcu_read_unlock(&vcpu->kvm->srcu, idx);
> > + /* kvm_io_bus_write returns -EOPNOTSUPP if it found no match. */
> > + return ret < 0 ? ret : 0;
> > +}
> > +
>
> What about the cookie?
This is the not-performance-optimized version which went through our
testing and which I'd like to see applied. I also have a not-yet-tested
patch that adds cookie support (see below), but I'd like to postpone
this to 3.10.
commit 8fce4a8a3478252f7ee2eb74d2732673f5911120
Author: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Date: Tue Feb 26 17:05:01 2013 +0100
virtio-ccw: ioeventfd: use cookies
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
index 1c01a99..bd2a013 100644
--- a/arch/s390/kvm/diag.c
+++ b/arch/s390/kvm/diag.c
@@ -108,22 +108,29 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
{
int ret, idx;
+ long cookie;
/* No virtio-ccw notification? Get out quickly. */
if (!vcpu->kvm->arch.css_support ||
(vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
return -EOPNOTSUPP;
+ cookie = vcpu->run->s.regs.gprs[4];
idx = srcu_read_lock(&vcpu->kvm->srcu);
/*
* The layout is as follows:
* - gpr 2 contains the subchannel id (passed as addr)
* - gpr 3 contains the virtqueue index (passed as datamatch)
+ * - gpr 4 contains the index on the bus (optionally)
*/
- ret = kvm_io_bus_write(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
- vcpu->run->s.regs.gprs[2],
- 8, &vcpu->run->s.regs.gprs[3]);
+ ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
+ vcpu->run->s.regs.gprs[2],
+ 8, &vcpu->run->s.regs.gprs[3],
+ &cookie);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
+ if (!ret)
+ /* Return cookie in gpr 2. */
+ vcpu->run->s.regs.gprs[2] = cookie;
/* kvm_io_bus_write returns -EOPNOTSUPP if it found no match. */
return ret < 0 ? ret : 0;
}
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 206247f..2f65a3a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -154,6 +154,8 @@ enum kvm_bus {
int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val);
+int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
+ int len, const void *val, long *cookie);
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len,
void *val);
int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7c188a3..b77ea5f 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2710,6 +2710,51 @@ int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
return -EOPNOTSUPP;
}
+/* kvm_io_bus_write_cookie - called under kvm->slots_lock */
+int kvm_io_bus_write_cookie(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
+ int len, const void *val, long *cookie)
+{
+ int idx, ret = -EOPNOTSUPP;
+ struct kvm_io_bus *bus;
+ struct kvm_io_range range;
+
+ range = (struct kvm_io_range) {
+ .addr = addr,
+ .len = len,
+ };
+
+ if (!cookie)
+ return -EINVAL;
+
+ bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
+
+ /* First try the device referenced by *cookie. */
+ if (kvm_io_bus_sort_cmp(&range, &bus->range[*cookie]) == 0)
+ if (!kvm_iodevice_write(bus->range[*cookie].dev, addr, len,
+ val))
+ return 0;
+
+ /*
+ * *cookie contained garbage; fall back to search and return the
+ * correct value in *cookie.
+ */
+ idx = kvm_io_bus_get_first_dev(bus, addr, len);
+ if (idx < 0)
+ goto out;
+
+ while (idx < bus->dev_count &&
+ kvm_io_bus_sort_cmp(&range, &bus->range[idx]) == 0) {
+ if (!kvm_iodevice_write(bus->range[idx].dev, addr, len, val)) {
+ ret = 0;
+ goto out;
+ }
+ idx++;
+ }
+out:
+ *cookie = idx;
+ return ret;
+}
+
/* kvm_io_bus_read - called under kvm->slots_lock */
int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val)
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