* [PATCH MANUALSEL 5.10 2/5] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus()
2021-11-23 16:36 [PATCH MANUALSEL 5.10 1/5] KVM: selftests: Fix kvm_vm_free() in cr4_cpuid_sync and vmx_tsc_adjust tests Sasha Levin
@ 2021-11-23 16:36 ` Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 3/5] KVM: PPC: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS Sasha Levin
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2021-11-23 16:36 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Vitaly Kuznetsov, Christian Borntraeger, Christian Borntraeger,
Paolo Bonzini, Sasha Levin, frankja, hca, gor, kvm, linux-s390
From: Vitaly Kuznetsov <vkuznets@redhat.com>
[ Upstream commit 82cc27eff4486f8e79ef8faac1af1f5573039aa4 ]
KVM_CAP_NR_VCPUS is a legacy advisory value which on other architectures
return num_online_cpus() caped by KVM_CAP_NR_VCPUS or something else
(ppc and arm64 are special cases). On s390, KVM_CAP_NR_VCPUS returns
the same as KVM_CAP_MAX_VCPUS and this may turn out to be a bad
'advice'. Switch s390 to returning caped num_online_cpus() too.
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Message-Id: <20211116163443.88707-6-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kvm/kvm-s390.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 00f03f363c9b0..25ca18ed07bdc 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -564,6 +564,8 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = KVM_MAX_VCPUS;
else if (sclp.has_esca && sclp.has_64bscao)
r = KVM_S390_ESCA_CPU_SLOTS;
+ if (ext == KVM_CAP_NR_VCPUS)
+ r = min_t(unsigned int, num_online_cpus(), r);
break;
case KVM_CAP_S390_COW:
r = MACHINE_HAS_ESOP;
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH MANUALSEL 5.10 3/5] KVM: PPC: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
2021-11-23 16:36 [PATCH MANUALSEL 5.10 1/5] KVM: selftests: Fix kvm_vm_free() in cr4_cpuid_sync and vmx_tsc_adjust tests Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 2/5] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus() Sasha Levin
@ 2021-11-23 16:36 ` Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 4/5] KVM: MIPS: " Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 5/5] KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus() Sasha Levin
3 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2021-11-23 16:36 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Vitaly Kuznetsov, Paolo Bonzini, Sasha Levin, mpe, paulus,
christophe.leroy, npiggin, farosas, clg, bharata, ravi.bangoria,
ndesaulniers, linuxppc-dev
From: Vitaly Kuznetsov <vkuznets@redhat.com>
[ Upstream commit b7915d55b1ac0e68a7586697fa2d06c018135c49 ]
It doesn't make sense to return the recommended maximum number of
vCPUs which exceeds the maximum possible number of vCPUs.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211116163443.88707-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kvm/powerpc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 543db9157f3b1..e0e8ec387970d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -641,9 +641,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
* implementations just count online CPUs.
*/
if (hv_enabled)
- r = num_present_cpus();
+ r = min_t(unsigned int, num_present_cpus(), KVM_MAX_VCPUS);
else
- r = num_online_cpus();
+ r = min_t(unsigned int, num_online_cpus(), KVM_MAX_VCPUS);
break;
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH MANUALSEL 5.10 4/5] KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
2021-11-23 16:36 [PATCH MANUALSEL 5.10 1/5] KVM: selftests: Fix kvm_vm_free() in cr4_cpuid_sync and vmx_tsc_adjust tests Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 2/5] KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus() Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 3/5] KVM: PPC: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS Sasha Levin
@ 2021-11-23 16:36 ` Sasha Levin
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 5/5] KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus() Sasha Levin
3 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2021-11-23 16:36 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Vitaly Kuznetsov, Paolo Bonzini, Sasha Levin, chenhuacai,
aleksandar.qemu.devel, tsbogend, linux-mips, kvm
From: Vitaly Kuznetsov <vkuznets@redhat.com>
[ Upstream commit 57a2e13ebdda8b65602b44ec8b80e385603eb84c ]
It doesn't make sense to return the recommended maximum number of
vCPUs which exceeds the maximum possible number of vCPUs.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211116163443.88707-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/mips/kvm/mips.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 3d6a7f5827b17..a9f1f37009850 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1074,7 +1074,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = 1;
break;
case KVM_CAP_NR_VCPUS:
- r = num_online_cpus();
+ r = min_t(unsigned int, num_online_cpus(), KVM_MAX_VCPUS);
break;
case KVM_CAP_MAX_VCPUS:
r = KVM_MAX_VCPUS;
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH MANUALSEL 5.10 5/5] KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
2021-11-23 16:36 [PATCH MANUALSEL 5.10 1/5] KVM: selftests: Fix kvm_vm_free() in cr4_cpuid_sync and vmx_tsc_adjust tests Sasha Levin
` (2 preceding siblings ...)
2021-11-23 16:36 ` [PATCH MANUALSEL 5.10 4/5] KVM: MIPS: " Sasha Levin
@ 2021-11-23 16:36 ` Sasha Levin
3 siblings, 0 replies; 5+ messages in thread
From: Sasha Levin @ 2021-11-23 16:36 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Vitaly Kuznetsov, Marc Zyngier, Paolo Bonzini, Sasha Levin,
catalin.marinas, will, linux-arm-kernel, kvmarm
From: Vitaly Kuznetsov <vkuznets@redhat.com>
[ Upstream commit f60a00d7295057cb4baea5a321501efc72794453 ]
Generally, it doesn't make sense to return the recommended maximum number
of vCPUs which exceeds the maximum possible number of vCPUs.
Note: ARM64 is special as the value returned by KVM_CAP_MAX_VCPUS differs
depending on whether it is a system-wide ioctl or a per-VM one. Previously,
KVM_CAP_NR_VCPUS didn't have this difference and it seems preferable to
keep the status quo. Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
which is what gets returned by system-wide KVM_CAP_MAX_VCPUS.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211116163443.88707-2-vkuznets@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kvm/arm.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 5bc978be80434..7737a10ba735f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -204,7 +204,14 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
r = 1;
break;
case KVM_CAP_NR_VCPUS:
- r = num_online_cpus();
+ /*
+ * ARM64 treats KVM_CAP_NR_CPUS differently from all other
+ * architectures, as it does not always bound it to
+ * KVM_CAP_MAX_VCPUS. It should not matter much because
+ * this is just an advisory value.
+ */
+ r = min_t(unsigned int, num_online_cpus(),
+ kvm_arm_default_max_vcpus());
break;
case KVM_CAP_MAX_VCPUS:
case KVM_CAP_MAX_VCPU_ID:
--
2.33.0
^ permalink raw reply related [flat|nested] 5+ messages in thread