Commit-ID: e3fbb040502eea324b2b2af59c49873f104c0df6
Gitweb: http://git.kernel.org/tip/e3fbb040502eea324b2b2af59c49873f104c0df6
Author: Sasha Levin <levinsasha928@xxxxxxxxx>
AuthorDate: Wed, 20 Jul 2011 14:21:12 +0300
Committer: Pekka Enberg <penberg@xxxxxxxxxx>
CommitDate: Wed, 20 Jul 2011 14:55:57 +0300
kvm tools: Update max VCPU limit
Use the newly introduced KVM_CAP_MAX_VCPUS to determine max VCPU count
the kernel side supports.
Using more VCPUs than the recommended limit will issue a warning, using more
than the absolute maximum will limit it down to the absolute maximum.
Note this patch contains a hack to define KVM_CAP_MAX_VCPUS and should be
removed when the kernel patch is merged with mainline.
Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
Signed-off-by: Pekka Enberg <penberg@xxxxxxxxxx>
---
tools/kvm/builtin-run.c | 6 +++++-
tools/kvm/include/kvm/kvm.h | 1 +
tools/kvm/kvm.c | 23 +++++++++++++++++++++--
3 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index af2e089..3345bf8 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -478,7 +478,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
struct framebuffer *fb = NULL;
unsigned int nr_online_cpus;
int exit_code = 0;
- int max_cpus;
+ int max_cpus, recommended_cpus;
char *hi;
int i;
void *ret;
@@ -578,10 +578,14 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
ioeventfd__init();
max_cpus = kvm__max_cpus(kvm);
+ recommended_cpus = kvm__recommended_cpus(kvm);
if (nrcpus > max_cpus) {
printf(" # Limit the number of CPUs to %d\n", max_cpus);
kvm->nrcpus = max_cpus;
+ } else if (nrcpus > recommended_cpus) {
+ printf(" # Warning: The maximum recommended amount of VCPUs"
+ " is %d\n", recommended_cpus);
}
kvm->nrcpus = nrcpus;
diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index 8792af2..eeb55b6 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -51,6 +51,7 @@ struct kvm {
};
struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name);
+int kvm__recommended_cpus(struct kvm *kvm);
int kvm__max_cpus(struct kvm *kvm);
void kvm__init_ram(struct kvm *kvm);
void kvm__delete(struct kvm *kvm);
diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index 248eaf4..107a922 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -304,17 +304,36 @@ void kvm__init_ram(struct kvm *kvm)
}
}
-int kvm__max_cpus(struct kvm *kvm)
+int kvm__recommended_cpus(struct kvm *kvm)
{
int ret;
ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_NR_VCPUS);
- if (ret < 0)
+ if (ret <= 0)
die_perror("KVM_CAP_NR_VCPUS");
return ret;
}
+/*
+ * The following hack should be removed once 'x86: Raise the hard
+ * VCPU count limit' makes it's way into the mainline.
+ */
+#ifndef KVM_CAP_MAX_VCPUS
+#define KVM_CAP_MAX_VCPUS 66
+#endif
+
+int kvm__max_cpus(struct kvm *kvm)
+{
+ int ret;
+
+ ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_MAX_VCPUS);
+ if (ret <= 0)
+ ret = kvm__recommended_cpus(kvm);
+
+ return ret;
+}
+
struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
{
struct kvm_pit_config pit_config = { .flags = 0, };
--
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