From: andre.przywara@arm.com (Andre Przywara)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 07/10] limit number of VCPUs on demand
Date: Wed, 17 Jun 2015 12:21:58 +0100 [thread overview]
Message-ID: <1434540121-21283-8-git-send-email-andre.przywara@arm.com> (raw)
In-Reply-To: <1434540121-21283-1-git-send-email-andre.przywara@arm.com>
Currently the ARM GIC checks the number of VCPUs against a fixed
limit, which is GICv2 specific. Don't pretend we know better than the
kernel and let's get rid of that explicit check.
Instead be more relaxed about KVM_CREATE_VCPU failing with EINVAL,
which is the way the kernel communicates having reached a VCPU limit.
If we see this and have at least brought up one VCPU already
successfully, then don't panic, but limit the number of VCPUs instead.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
arm/gic.c | 6 ------
arm/kvm-cpu.c | 11 +++++++++--
kvm-cpu.c | 7 +++++++
3 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arm/gic.c b/arm/gic.c
index 99f0d2b..05f85a2 100644
--- a/arm/gic.c
+++ b/arm/gic.c
@@ -84,12 +84,6 @@ int gic__create(struct kvm *kvm)
{
int err;
- if (kvm->nrcpus > GIC_MAX_CPUS) {
- pr_warning("%d CPUS greater than maximum of %d -- truncating\n",
- kvm->nrcpus, GIC_MAX_CPUS);
- kvm->nrcpus = GIC_MAX_CPUS;
- }
-
/* Try the new way first, and fallback on legacy method otherwise */
err = gic__create_device(kvm);
if (err)
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 7780251..c1cf51d 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -47,12 +47,19 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
};
vcpu = calloc(1, sizeof(struct kvm_cpu));
- if (!vcpu)
+ if (!vcpu) {
+ errno = ENOMEM;
return NULL;
+ }
vcpu->vcpu_fd = ioctl(kvm->vm_fd, KVM_CREATE_VCPU, cpu_id);
- if (vcpu->vcpu_fd < 0)
+ if (vcpu->vcpu_fd < 0) {
+ if (errno == EINVAL) {
+ free(vcpu);
+ return NULL;
+ }
die_perror("KVM_CREATE_VCPU ioctl");
+ }
mmap_size = ioctl(kvm->sys_fd, KVM_GET_VCPU_MMAP_SIZE, 0);
if (mmap_size < 0)
diff --git a/kvm-cpu.c b/kvm-cpu.c
index 5d90664..7a9d689 100644
--- a/kvm-cpu.c
+++ b/kvm-cpu.c
@@ -222,11 +222,18 @@ int kvm_cpu__init(struct kvm *kvm)
for (i = 0; i < kvm->nrcpus; i++) {
kvm->cpus[i] = kvm_cpu__arch_init(kvm, i);
if (!kvm->cpus[i]) {
+ if (i > 0 && errno == EINVAL)
+ break;
pr_warning("unable to initialize KVM VCPU");
goto fail_alloc;
}
}
+ if (i < kvm->nrcpus) {
+ kvm->nrcpus = i;
+ printf(" # The kernel limits the number of CPUs to %d\n", i);
+ }
+
return 0;
fail_alloc:
--
2.3.5
WARNING: multiple messages have this Message-ID (diff)
From: Andre Przywara <andre.przywara@arm.com>
To: will.deacon@arm.com, marc.zyngier@arm.com
Cc: penberg@kernel.org, kvmarm@lists.cs.columbia.edu,
kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 07/10] limit number of VCPUs on demand
Date: Wed, 17 Jun 2015 12:21:58 +0100 [thread overview]
Message-ID: <1434540121-21283-8-git-send-email-andre.przywara@arm.com> (raw)
In-Reply-To: <1434540121-21283-1-git-send-email-andre.przywara@arm.com>
Currently the ARM GIC checks the number of VCPUs against a fixed
limit, which is GICv2 specific. Don't pretend we know better than the
kernel and let's get rid of that explicit check.
Instead be more relaxed about KVM_CREATE_VCPU failing with EINVAL,
which is the way the kernel communicates having reached a VCPU limit.
If we see this and have at least brought up one VCPU already
successfully, then don't panic, but limit the number of VCPUs instead.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
arm/gic.c | 6 ------
arm/kvm-cpu.c | 11 +++++++++--
kvm-cpu.c | 7 +++++++
3 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arm/gic.c b/arm/gic.c
index 99f0d2b..05f85a2 100644
--- a/arm/gic.c
+++ b/arm/gic.c
@@ -84,12 +84,6 @@ int gic__create(struct kvm *kvm)
{
int err;
- if (kvm->nrcpus > GIC_MAX_CPUS) {
- pr_warning("%d CPUS greater than maximum of %d -- truncating\n",
- kvm->nrcpus, GIC_MAX_CPUS);
- kvm->nrcpus = GIC_MAX_CPUS;
- }
-
/* Try the new way first, and fallback on legacy method otherwise */
err = gic__create_device(kvm);
if (err)
diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c
index 7780251..c1cf51d 100644
--- a/arm/kvm-cpu.c
+++ b/arm/kvm-cpu.c
@@ -47,12 +47,19 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id)
};
vcpu = calloc(1, sizeof(struct kvm_cpu));
- if (!vcpu)
+ if (!vcpu) {
+ errno = ENOMEM;
return NULL;
+ }
vcpu->vcpu_fd = ioctl(kvm->vm_fd, KVM_CREATE_VCPU, cpu_id);
- if (vcpu->vcpu_fd < 0)
+ if (vcpu->vcpu_fd < 0) {
+ if (errno == EINVAL) {
+ free(vcpu);
+ return NULL;
+ }
die_perror("KVM_CREATE_VCPU ioctl");
+ }
mmap_size = ioctl(kvm->sys_fd, KVM_GET_VCPU_MMAP_SIZE, 0);
if (mmap_size < 0)
diff --git a/kvm-cpu.c b/kvm-cpu.c
index 5d90664..7a9d689 100644
--- a/kvm-cpu.c
+++ b/kvm-cpu.c
@@ -222,11 +222,18 @@ int kvm_cpu__init(struct kvm *kvm)
for (i = 0; i < kvm->nrcpus; i++) {
kvm->cpus[i] = kvm_cpu__arch_init(kvm, i);
if (!kvm->cpus[i]) {
+ if (i > 0 && errno == EINVAL)
+ break;
pr_warning("unable to initialize KVM VCPU");
goto fail_alloc;
}
}
+ if (i < kvm->nrcpus) {
+ kvm->nrcpus = i;
+ printf(" # The kernel limits the number of CPUs to %d\n", i);
+ }
+
return 0;
fail_alloc:
--
2.3.5
next prev parent reply other threads:[~2015-06-17 11:21 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-17 11:21 [PATCH v3 00/10] kvmtool: arm64: GICv3 guest support Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 01/10] AArch64: Reserve two 64k pages for GIC CPU interface Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 02/10] AArch{32, 64}: use KVM_CREATE_DEVICE & co to instanciate the GIC Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 03/10] irq: add irq__get_nr_allocated_lines Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 04/10] AArch{32, 64}: dynamically configure the number of GIC interrupts Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 05/10] arm: finish VGIC initialisation explicitly Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 06/10] arm: simplify MMIO dispatching Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 12:48 ` Marc Zyngier
2015-06-17 12:48 ` Marc Zyngier
2015-06-17 13:49 ` Andre Przywara
2015-06-17 13:49 ` Andre Przywara
2015-06-17 14:06 ` Marc Zyngier
2015-06-17 14:06 ` Marc Zyngier
2015-06-24 13:30 ` Andre Przywara
2015-06-24 13:30 ` Andre Przywara
2015-06-24 17:56 ` Will Deacon
2015-06-24 17:56 ` Will Deacon
2015-06-17 11:21 ` Andre Przywara [this message]
2015-06-17 11:21 ` [PATCH v3 07/10] limit number of VCPUs on demand Andre Przywara
2015-06-17 12:53 ` Marc Zyngier
2015-06-17 12:53 ` Marc Zyngier
2015-06-17 13:14 ` Andre Przywara
2015-06-17 13:14 ` Andre Przywara
2015-06-17 11:21 ` [PATCH v3 08/10] arm: prepare for instantiating different IRQ chip devices Andre Przywara
2015-06-17 11:21 ` Andre Przywara
2015-06-17 13:06 ` Marc Zyngier
2015-06-17 13:06 ` Marc Zyngier
2015-06-17 11:22 ` [PATCH v3 09/10] arm: add support for supplying GICv3 redistributor addresses Andre Przywara
2015-06-17 11:22 ` Andre Przywara
2015-06-17 13:09 ` Marc Zyngier
2015-06-17 13:09 ` Marc Zyngier
2015-06-17 11:22 ` [PATCH v3 10/10] arm: use new irqchip parameter to create different vGIC types Andre Przywara
2015-06-17 11:22 ` Andre Przywara
2015-06-17 13:16 ` Marc Zyngier
2015-06-17 13:16 ` Marc Zyngier
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