On 23/09/2019 17:44, Greg Kurz wrote:
> Add a new attribute to both legacy and native XIVE KVM devices so that
> userspace can require less interrupt servers than the current default
> (KVM_MAX_VCPUS, 2048). This will allow to allocate less VPs in OPAL,
> and likely increase the number of VMs that can run with an in-kernel
> XIVE implementation.
>
> 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@xxxxxxxx>
Reviewed-by: Cédric Le Goater <clg@xxxxxxxx>
C.
> ---
> 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..1cf9621f8341 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_VCPUS.
> + -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..fd418b907d0e 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_KVM_VCPUS.
> + -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 4a333dcfddd8..c1901583e6c0 100644
> --- a/arch/powerpc/kvm/book3s_xive.c
> +++ b/arch/powerpc/kvm/book3s_xive.c
> @@ -1905,6 +1905,11 @@ 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;
> }
> @@ -1930,6 +1935,11 @@ 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 5e18364d52a9..8e954c5d5efb 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;
>
