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[Qemu-devel] [PULL 08/13] PPC/KVM: early validation of vcpu id
From: |
David Gibson |
Subject: |
[Qemu-devel] [PULL 08/13] PPC/KVM: early validation of vcpu id |
Date: |
Fri, 27 May 2016 13:04:53 +1000 |
From: Greg Kurz <address@hidden>
The KVM API restricts vcpu ids to be < KVM_CAP_MAX_VCPUS. On PowerPC
targets, depending on the number of threads per core in the host and
in the guest, some topologies do generate higher vcpu ids actually.
When this happens, QEMU bails out with the following error:
kvm_init_vcpu failed: Invalid argument
The KVM_CREATE_VCPU ioctl has several EINVAL return paths, so it is
not possible to fully disambiguate.
This patch adds a check in the code that computes vcpu ids, so that
we can detect the error earlier, and print a friendlier message instead
of calling KVM_CREATE_VCPU with an obviously bogus vcpu id.
Signed-off-by: Greg Kurz <address@hidden>
Signed-off-by: David Gibson <address@hidden>
---
include/sysemu/kvm.h | 2 ++
kvm-all.c | 6 ++++++
target-ppc/translate_init.c | 8 ++++++++
3 files changed, 16 insertions(+)
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index f9f00e2..f357ccd 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -345,6 +345,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s);
int kvm_arch_init_vcpu(CPUState *cpu);
+bool kvm_vcpu_id_is_valid(int vcpu_id);
+
/* Returns VCPU ID to be used on KVM_CREATE_VCPU ioctl() */
unsigned long kvm_arch_vcpu_id(CPUState *cpu);
diff --git a/kvm-all.c b/kvm-all.c
index f9ae8f9..e56f385 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1459,6 +1459,12 @@ static int kvm_max_vcpus(KVMState *s)
return (ret) ? ret : kvm_recommended_vcpus(s);
}
+bool kvm_vcpu_id_is_valid(int vcpu_id)
+{
+ KVMState *s = KVM_STATE(current_machine->accelerator);
+ return vcpu_id >= 0 && vcpu_id < kvm_max_vcpus(s);
+}
+
static int kvm_init(MachineState *ms)
{
MachineClass *mc = MACHINE_GET_CLASS(ms);
diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index 954195f..a003c10 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -9231,6 +9231,14 @@ static void ppc_cpu_realizefn(DeviceState *dev, Error
**errp)
#if !defined(CONFIG_USER_ONLY)
cpu->cpu_dt_id = (cs->cpu_index / smp_threads) * max_smt
+ (cs->cpu_index % smp_threads);
+
+ if (kvm_enabled() && !kvm_vcpu_id_is_valid(cpu->cpu_dt_id)) {
+ error_setg(errp, "Can't create CPU with id %d in KVM", cpu->cpu_dt_id);
+ error_append_hint(errp, "Adjust the number of cpus to %d "
+ "or try to raise the number of threads per core\n",
+ cpu->cpu_dt_id * smp_threads / max_smt);
+ return;
+ }
#endif
if (tcg_enabled()) {
--
2.5.5
- [Qemu-devel] [PULL 04/13] target-ppc: Cleanups to rldinm, rldnm, rldimi, (continued)
- [Qemu-devel] [PULL 04/13] target-ppc: Cleanups to rldinm, rldnm, rldimi, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 03/13] target-ppc: Use 32-bit rotate instead of deposit + 64-bit rotate, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 07/13] Added negative check for get_image_size(), David Gibson, 2016/05/26
- [Qemu-devel] [PULL 06/13] hw/net/spapr_llan: Provide counter with dropped rx frames to the guest, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 13/13] MAINTAINERS: Add David Gibson as ppc maintainer, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 09/13] spapr: ensure device trees are always associated with DRC, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 12/13] spapr_iommu: Move table allocation to helpers, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 10/13] spapr_pci: Use correct DMA LIOBN when composing the device tree, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 01/13] target-ppc: Correct KVM synchronization for ppc_hash64_set_external_hpt(), David Gibson, 2016/05/26
- [Qemu-devel] [PULL 11/13] spapr_iommu: Finish renaming vfio_accel to need_vfio, David Gibson, 2016/05/26
- [Qemu-devel] [PULL 08/13] PPC/KVM: early validation of vcpu id,
David Gibson <=
- [Qemu-devel] [PULL 05/13] hw/net/spapr_llan: Delay flushing of the RX queue while adding new RX buffers, David Gibson, 2016/05/26
- Re: [Qemu-devel] [PULL 00/13] ppc-for-2.7 queue 20160527, Peter Maydell, 2016/05/27