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 groug@kaod.org Reviewed-by: Cédric Le Goater clg@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;