Add a new attribute to both XIVE and XICS-on-XIVE KVM devices so that
userspace can tell how many interrupt servers it needs. If a VM needs
less than the current default of KVM_MAX_VCPUS (2048), we can allocate
less VPs in OPAL. Combined with a core stride (VSMT) that matches the
number of guest threads per core, this may substantially increases the
number of VMs that can run concurrently with an in-kernel XIVE device.
Since the legacy XIVE KVM device is exposed to userspace through the
XICS KVM API, a new attribute group is added to it for this purpose.
While here, fix the syntax of the existing KVM_DEV_XICS_GRP_SOURCES
in the XICS documentation.
Signed-off-by: Greg Kurz <gr...@kaod.org>
Reviewed-by: Cédric Le Goater <c...@kaod.org>
---
v2: - changelog update
---
Documentation/virt/kvm/devices/xics.txt | 14 ++++++++++++--
Documentation/virt/kvm/devices/xive.txt | 8 ++++++++
arch/powerpc/include/uapi/asm/kvm.h | 3 +++
arch/powerpc/kvm/book3s_xive.c | 10 ++++++++++
arch/powerpc/kvm/book3s_xive_native.c | 3 +++
5 files changed, 36 insertions(+), 2 deletions(-)
diff --git a/Documentation/virt/kvm/devices/xics.txt
b/Documentation/virt/kvm/devices/xics.txt
index 42864935ac5d..423332dda7bc 100644
--- a/Documentation/virt/kvm/devices/xics.txt
+++ b/Documentation/virt/kvm/devices/xics.txt
@@ -3,9 +3,19 @@ XICS interrupt controller
Device type supported: KVM_DEV_TYPE_XICS
Groups:
- KVM_DEV_XICS_SOURCES
+ 1. KVM_DEV_XICS_GRP_SOURCES
Attributes: One per interrupt source, indexed by the source number.
+ 2. KVM_DEV_XICS_GRP_CTRL
+ Attributes:
+ 2.1 KVM_DEV_XICS_NR_SERVERS (write only)
+ The kvm_device_attr.addr points to a __u32 value which is the number of
+ interrupt server numbers (ie, highest possible vcpu id plus one).
+ Errors:
+ -EINVAL: Value greater than KVM_MAX_VCPU_ID.
+ -EFAULT: Invalid user pointer for attr->addr.
+ -EBUSY: A vcpu is already connected to the device.
+
This device emulates the XICS (eXternal Interrupt Controller
Specification) defined in PAPR. The XICS has a set of interrupt
sources, each identified by a 20-bit source number, and a set of
@@ -38,7 +48,7 @@ least-significant end of the word:
Each source has 64 bits of state that can be read and written using
the KVM_GET_DEVICE_ATTR and KVM_SET_DEVICE_ATTR ioctls, specifying the
-KVM_DEV_XICS_SOURCES attribute group, with the attribute number being
+KVM_DEV_XICS_GRP_SOURCES attribute group, with the attribute number being
the interrupt source number. The 64 bit state word has the following
bitfields, starting from the least-significant end of the word:
diff --git a/Documentation/virt/kvm/devices/xive.txt
b/Documentation/virt/kvm/devices/xive.txt
index 9a24a4525253..f5d1d6b5af61 100644
--- a/Documentation/virt/kvm/devices/xive.txt
+++ b/Documentation/virt/kvm/devices/xive.txt
@@ -78,6 +78,14 @@ the legacy interrupt mode, referred as XICS (POWER7/8).
migrating the VM.
Errors: none
+ 1.3 KVM_DEV_XIVE_NR_SERVERS (write only)
+ The kvm_device_attr.addr points to a __u32 value which is the number of
+ interrupt server numbers (ie, highest possible vcpu id plus one).
+ Errors:
+ -EINVAL: Value greater than KVM_MAX_VCPU_ID.
+ -EFAULT: Invalid user pointer for attr->addr.
+ -EBUSY: A vCPU is already connected to the device.
+
2. KVM_DEV_XIVE_GRP_SOURCE (write only)
Initializes a new source in the XIVE device and mask it.
Attributes:
diff --git a/arch/powerpc/include/uapi/asm/kvm.h
b/arch/powerpc/include/uapi/asm/kvm.h
index b0f72dea8b11..264e266a85bf 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -667,6 +667,8 @@ struct kvm_ppc_cpu_char {
/* PPC64 eXternal Interrupt Controller Specification */
#define KVM_DEV_XICS_GRP_SOURCES 1 /* 64-bit source attributes */
+#define KVM_DEV_XICS_GRP_CTRL 2
+#define KVM_DEV_XICS_NR_SERVERS 1
/* Layout of 64-bit source attribute values */
#define KVM_XICS_DESTINATION_SHIFT 0
@@ -683,6 +685,7 @@ struct kvm_ppc_cpu_char {
#define KVM_DEV_XIVE_GRP_CTRL 1
#define KVM_DEV_XIVE_RESET 1
#define KVM_DEV_XIVE_EQ_SYNC 2
+#define KVM_DEV_XIVE_NR_SERVERS 3
#define KVM_DEV_XIVE_GRP_SOURCE 2 /* 64-bit source
identifier */
#define KVM_DEV_XIVE_GRP_SOURCE_CONFIG 3 /* 64-bit source identifier */
#define KVM_DEV_XIVE_GRP_EQ_CONFIG 4 /* 64-bit EQ identifier */
diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index 6c35b3d95986..66858b7d3c6b 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -1911,6 +1911,11 @@ static int xive_set_attr(struct kvm_device *dev, struct
kvm_device_attr *attr)
switch (attr->group) {
case KVM_DEV_XICS_GRP_SOURCES:
return xive_set_source(xive, attr->attr, attr->addr);
+ case KVM_DEV_XICS_GRP_CTRL:
+ switch (attr->attr) {
+ case KVM_DEV_XICS_NR_SERVERS:
+ return kvmppc_xive_set_nr_servers(xive, attr->addr);
+ }
}
return -ENXIO;
}
@@ -1936,6 +1941,11 @@ static int xive_has_attr(struct kvm_device *dev, struct
kvm_device_attr *attr)
attr->attr < KVMPPC_XICS_NR_IRQS)
return 0;
break;
+ case KVM_DEV_XICS_GRP_CTRL:
+ switch (attr->attr) {
+ case KVM_DEV_XICS_NR_SERVERS:
+ return 0;
+ }
}
return -ENXIO;
}
diff --git a/arch/powerpc/kvm/book3s_xive_native.c
b/arch/powerpc/kvm/book3s_xive_native.c
index 8ab333eabeef..34bd123fa024 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -921,6 +921,8 @@ static int kvmppc_xive_native_set_attr(struct kvm_device
*dev,
return kvmppc_xive_reset(xive);
case KVM_DEV_XIVE_EQ_SYNC:
return kvmppc_xive_native_eq_sync(xive);
+ case KVM_DEV_XIVE_NR_SERVERS:
+ return kvmppc_xive_set_nr_servers(xive, attr->addr);
}
break;
case KVM_DEV_XIVE_GRP_SOURCE:
@@ -960,6 +962,7 @@ static int kvmppc_xive_native_has_attr(struct kvm_device
*dev,
switch (attr->attr) {
case KVM_DEV_XIVE_RESET:
case KVM_DEV_XIVE_EQ_SYNC:
+ case KVM_DEV_XIVE_NR_SERVERS:
return 0;
}
break;
