On a modern server-class ppc host with the following CPU topology:
Architecture: ppc64le
Byte Order: Little Endian
CPU(s): 32
On-line CPU(s) list: 0,8,16,24
Off-line CPU(s) list: 1-7,9-15,17-23,25-31
Thread(s) per core: 1
If both KVM PR and KVM HV loaded and we pass:
-machine pseries,accel=kvm,kvm-type=PR -smp 8
We expect QEMU to warn that this exceeds the number of online CPUs:
Warning: Number of SMP cpus requested (8) exceeds the recommended
cpus supported by KVM (4)
Warning: Number of hotpluggable cpus requested (8) exceeds the
recommended cpus supported by KVM (4)
but nothing is printed...
This happens because on ppc the KVM_CAP_NR_VCPUS capability is VM
specific ndreally depends on the KVM type, but we currently use it
as a global capability. And KVM returns a fallback value based on
KVM HV being present. Maybe KVM on POWER shouldn't presume anything
as long as it doesn't have a VM, but in all cases, we should call
KVM_CREATE_VM first and use KVM_CAP_NR_VCPUS as a VM capability.
This patch hence changes kvm_recommended_vcpus() accordingly and
moves the sanity checking of smp_cpus after the VM creation.
It is okay for the other archs that also implement KVM_CAP_NR_VCPUS,
ie, mips, s390, x86 and arm, because they don't depend on the VM
being created or not.
Signed-off-by: Greg Kurz <groug@kaod.org>
---
accel/kvm/kvm-all.c | 45 +++++++++++++++++++++++----------------------
1 file changed, 23 insertions(+), 22 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 323c567cfb68..d10534de2da1 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1533,7 +1533,7 @@ static void kvm_irqchip_create(MachineState *machine, KVMState *s)
*/
static int kvm_recommended_vcpus(KVMState *s)
{
- int ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS);
+ int ret = kvm_vm_check_extension(s, KVM_CAP_NR_VCPUS);
return (ret) ? ret : 4;
}
@@ -1623,27 +1623,6 @@ static int kvm_init(MachineState *ms)
s->nr_slots = 32;
}
- /* check the vcpu limits */
- soft_vcpus_limit = kvm_recommended_vcpus(s);
- hard_vcpus_limit = kvm_max_vcpus(s);
-
- while (nc->name) {
- if (nc->num > soft_vcpus_limit) {
- fprintf(stderr,
- "Warning: Number of %s cpus requested (%d) exceeds "
- "the recommended cpus supported by KVM (%d)\n",
- nc->name, nc->num, soft_vcpus_limit);
-
- if (nc->num > hard_vcpus_limit) {
- fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
- "the maximum cpus supported by KVM (%d)\n",
- nc->name, nc->num, hard_vcpus_limit);
- exit(1);
- }
- }
- nc++;
- }
-
kvm_type = qemu_opt_get(qemu_get_machine_opts(), "kvm-type");
if (mc->kvm_type) {
type = mc->kvm_type(kvm_type);
@@ -1678,6 +1657,28 @@ static int kvm_init(MachineState *ms)
}
s->vmfd = ret;
+
+ /* check the vcpu limits */
+ soft_vcpus_limit = kvm_recommended_vcpus(s);
+ hard_vcpus_limit = kvm_max_vcpus(s);
+
+ while (nc->name) {
+ if (nc->num > soft_vcpus_limit) {
+ fprintf(stderr,
+ "Warning: Number of %s cpus requested (%d) exceeds "
+ "the recommended cpus supported by KVM (%d)\n",
+ nc->name, nc->num, soft_vcpus_limit);
+
+ if (nc->num > hard_vcpus_limit) {
+ fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
+ "the maximum cpus supported by KVM (%d)\n",
+ nc->name, nc->num, hard_vcpus_limit);
+ exit(1);
+ }
+ }
+ nc++;
+ }
+
missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);
if (!missing_cap) {
missing_cap =
On Thu, Sep 14, 2017 at 09:25:32PM +0200, Greg Kurz wrote:
1;4803;0c> On a modern server-class ppc host with the following CPU topology:
>
> Architecture: ppc64le
> Byte Order: Little Endian
> CPU(s): 32
> On-line CPU(s) list: 0,8,16,24
> Off-line CPU(s) list: 1-7,9-15,17-23,25-31
> Thread(s) per core: 1
>
> If both KVM PR and KVM HV loaded and we pass:
>
> -machine pseries,accel=kvm,kvm-type=PR -smp 8
>
> We expect QEMU to warn that this exceeds the number of online CPUs:
>
> Warning: Number of SMP cpus requested (8) exceeds the recommended
> cpus supported by KVM (4)
> Warning: Number of hotpluggable cpus requested (8) exceeds the
> recommended cpus supported by KVM (4)
>
> but nothing is printed...
>
> This happens because on ppc the KVM_CAP_NR_VCPUS capability is VM
> specific ndreally depends on the KVM type, but we currently use it
> as a global capability. And KVM returns a fallback value based on
> KVM HV being present. Maybe KVM on POWER shouldn't presume anything
> as long as it doesn't have a VM, but in all cases, we should call
> KVM_CREATE_VM first and use KVM_CAP_NR_VCPUS as a VM capability.
>
> This patch hence changes kvm_recommended_vcpus() accordingly and
> moves the sanity checking of smp_cpus after the VM creation.
>
> It is okay for the other archs that also implement KVM_CAP_NR_VCPUS,
> ie, mips, s390, x86 and arm, because they don't depend on the VM
> being created or not.
>
> Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> ---
> accel/kvm/kvm-all.c | 45 +++++++++++++++++++++++----------------------
> 1 file changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 323c567cfb68..d10534de2da1 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -1533,7 +1533,7 @@ static void kvm_irqchip_create(MachineState *machine, KVMState *s)
> */
> static int kvm_recommended_vcpus(KVMState *s)
> {
> - int ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS);
> + int ret = kvm_vm_check_extension(s, KVM_CAP_NR_VCPUS);
> return (ret) ? ret : 4;
> }
>
> @@ -1623,27 +1623,6 @@ static int kvm_init(MachineState *ms)
> s->nr_slots = 32;
> }
>
> - /* check the vcpu limits */
> - soft_vcpus_limit = kvm_recommended_vcpus(s);
> - hard_vcpus_limit = kvm_max_vcpus(s);
> -
> - while (nc->name) {
> - if (nc->num > soft_vcpus_limit) {
> - fprintf(stderr,
> - "Warning: Number of %s cpus requested (%d) exceeds "
> - "the recommended cpus supported by KVM (%d)\n",
> - nc->name, nc->num, soft_vcpus_limit);
> -
> - if (nc->num > hard_vcpus_limit) {
> - fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
> - "the maximum cpus supported by KVM (%d)\n",
> - nc->name, nc->num, hard_vcpus_limit);
> - exit(1);
> - }
> - }
> - nc++;
> - }
> -
> kvm_type = qemu_opt_get(qemu_get_machine_opts(), "kvm-type");
> if (mc->kvm_type) {
> type = mc->kvm_type(kvm_type);
> @@ -1678,6 +1657,28 @@ static int kvm_init(MachineState *ms)
> }
>
> s->vmfd = ret;
> +
> + /* check the vcpu limits */
> + soft_vcpus_limit = kvm_recommended_vcpus(s);
> + hard_vcpus_limit = kvm_max_vcpus(s);
> +
> + while (nc->name) {
> + if (nc->num > soft_vcpus_limit) {
> + fprintf(stderr,
> + "Warning: Number of %s cpus requested (%d) exceeds "
> + "the recommended cpus supported by KVM (%d)\n",
> + nc->name, nc->num, soft_vcpus_limit);
> +
> + if (nc->num > hard_vcpus_limit) {
> + fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
> + "the maximum cpus supported by KVM (%d)\n",
> + nc->name, nc->num, hard_vcpus_limit);
> + exit(1);
> + }
> + }
> + nc++;
> + }
> +
> missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);
> if (!missing_cap) {
> missing_cap =
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
On 14.09.2017 21:25, Greg Kurz wrote:
> On a modern server-class ppc host with the following CPU topology:
>
> Architecture: ppc64le
> Byte Order: Little Endian
> CPU(s): 32
> On-line CPU(s) list: 0,8,16,24
> Off-line CPU(s) list: 1-7,9-15,17-23,25-31
> Thread(s) per core: 1
>
> If both KVM PR and KVM HV loaded and we pass:
>
> -machine pseries,accel=kvm,kvm-type=PR -smp 8
>
> We expect QEMU to warn that this exceeds the number of online CPUs:
>
> Warning: Number of SMP cpus requested (8) exceeds the recommended
> cpus supported by KVM (4)
> Warning: Number of hotpluggable cpus requested (8) exceeds the
> recommended cpus supported by KVM (4)
>
> but nothing is printed...
>
> This happens because on ppc the KVM_CAP_NR_VCPUS capability is VM
> specific ndreally depends on the KVM type, but we currently use it
> as a global capability. And KVM returns a fallback value based on
> KVM HV being present. Maybe KVM on POWER shouldn't presume anything
> as long as it doesn't have a VM, but in all cases, we should call
> KVM_CREATE_VM first and use KVM_CAP_NR_VCPUS as a VM capability.
>
> This patch hence changes kvm_recommended_vcpus() accordingly and
> moves the sanity checking of smp_cpus after the VM creation.
>
> It is okay for the other archs that also implement KVM_CAP_NR_VCPUS,
> ie, mips, s390, x86 and arm, because they don't depend on the VM
> being created or not.
>
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
> accel/kvm/kvm-all.c | 45 +++++++++++++++++++++++----------------------
> 1 file changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 323c567cfb68..d10534de2da1 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -1533,7 +1533,7 @@ static void kvm_irqchip_create(MachineState *machine, KVMState *s)
> */
> static int kvm_recommended_vcpus(KVMState *s)
> {
> - int ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS);
> + int ret = kvm_vm_check_extension(s, KVM_CAP_NR_VCPUS);
> return (ret) ? ret : 4;
> }
>
> @@ -1623,27 +1623,6 @@ static int kvm_init(MachineState *ms)
> s->nr_slots = 32;
> }
>
> - /* check the vcpu limits */
> - soft_vcpus_limit = kvm_recommended_vcpus(s);
> - hard_vcpus_limit = kvm_max_vcpus(s);
> -
> - while (nc->name) {
> - if (nc->num > soft_vcpus_limit) {
> - fprintf(stderr,
> - "Warning: Number of %s cpus requested (%d) exceeds "
> - "the recommended cpus supported by KVM (%d)\n",
> - nc->name, nc->num, soft_vcpus_limit);
> -
> - if (nc->num > hard_vcpus_limit) {
> - fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
> - "the maximum cpus supported by KVM (%d)\n",
> - nc->name, nc->num, hard_vcpus_limit);
> - exit(1);
> - }
> - }
> - nc++;
> - }
> -
> kvm_type = qemu_opt_get(qemu_get_machine_opts(), "kvm-type");
> if (mc->kvm_type) {
> type = mc->kvm_type(kvm_type);
> @@ -1678,6 +1657,28 @@ static int kvm_init(MachineState *ms)
> }
>
> s->vmfd = ret;
> +
> + /* check the vcpu limits */
> + soft_vcpus_limit = kvm_recommended_vcpus(s);
> + hard_vcpus_limit = kvm_max_vcpus(s);
> +
> + while (nc->name) {
> + if (nc->num > soft_vcpus_limit) {
> + fprintf(stderr,
> + "Warning: Number of %s cpus requested (%d) exceeds "
> + "the recommended cpus supported by KVM (%d)\n",
> + nc->name, nc->num, soft_vcpus_limit);
> +
> + if (nc->num > hard_vcpus_limit) {
> + fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
> + "the maximum cpus supported by KVM (%d)\n",
> + nc->name, nc->num, hard_vcpus_limit);
> + exit(1);
> + }
> + }
> + nc++;
> + }
> +
> missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);
> if (!missing_cap) {
> missing_cap =
>
Reviewed-by: Thomas Huth <thuth@redhat.com>
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