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authorThiago Jung Bauermann2020-08-26 07:55:30 +0200
committerDavid Gibson2020-09-08 02:08:43 +0200
commit554c2169e9251ca2829ab968bd9ba5641a5abe1d (patch)
tree6372516d8119f09e8e5c8c7cfe5e34d8e58f7278
parenttarget/arm: Move setting of CPU halted state to generic code (diff)
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ppc/spapr: Use start-powered-off CPUState property
PowerPC sPAPR CPUs start in the halted state, and spapr_reset_vcpu() attempts to implement this by setting CPUState::halted to 1. But that's too late for the case of hotplugged CPUs in a machine configure with 2 or more threads per core. By then, other parts of QEMU have already caused the vCPU to run in an unitialized state a couple of times. For example, ppc_cpu_reset() calls ppc_tlb_invalidate_all(), which ends up calling async_run_on_cpu(). This kicks the new vCPU while it has CPUState::halted = 0, causing QEMU to issue a KVM_RUN ioctl on the new vCPU before the guest is able to make the start-cpu RTAS call to initialize its register state. This problem doesn't seem to cause visible issues for regular guests, but on a secure guest running under the Ultravisor it does. The Ultravisor relies on being able to snoop on the start-cpu RTAS call to map vCPUs to guests, and this issue causes it to see a stray vCPU that doesn't belong to any guest. Fix by setting the start-powered-off CPUState property in spapr_create_vcpu(), which makes cpu_common_reset() initialize CPUState::halted to 1 at an earlier moment. Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Greg Kurz <groug@kaod.org> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Message-Id: <20200826055535.951207-4-bauerman@linux.ibm.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
-rw-r--r--hw/ppc/spapr_cpu_core.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index c4f47dcc04..2125fdac34 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -36,11 +36,6 @@ static void spapr_reset_vcpu(PowerPCCPU *cpu)
cpu_reset(cs);
- /* All CPUs start halted. CPU0 is unhalted from the machine level
- * reset code and the rest are explicitly started up by the guest
- * using an RTAS call */
- cs->halted = 1;
-
env->spr[SPR_HIOR] = 0;
lpcr = env->spr[SPR_LPCR];
@@ -274,6 +269,11 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp)
cs = CPU(obj);
cpu = POWERPC_CPU(obj);
+ /*
+ * All CPUs start halted. CPU0 is unhalted from the machine level reset code
+ * and the rest are explicitly started up by the guest using an RTAS call.
+ */
+ cs->start_powered_off = true;
cs->cpu_index = cc->core_id + i;
spapr_set_vcpu_id(cpu, cs->cpu_index, &local_err);
if (local_err) {